AMERICAN MUSEUM Novitates
PUBLISHED BY THE AMERICAN MUSEUM OF NATURAL HISTORY CENTRAL PARK WEST AT 79TH STREET, NEW YORK, NY 10024
Number 3421, 47 pp., 15 figures, 12 tables December 9, 2003
A New Species of Thomasomys (Rodentia: Muridae) from Eastern Ecuador, with Remarks on Mammalian Diversity and
Biogeography in the Cordillera Oriental
ROBERT S. VOSS!
CONTENTS PRD SUT ACI ry Peagtig sh rotons, x. sgersee rine te ePID Putte PIS gn opts 5 Legere Ee Ns og RONEN PAM LD Rica ons, 4.38 2 ETTORE vet ee ea rane teey yh Ue ie ete cer ty Pe aed ss cee yh onste ay WY Be phair eV are eae 2 hes Papa late GaN COB et sc ae Pee cece eee eh oe re nate Aker, tara Nakata aR CE Rie 3 INEate mrallsianich MICE OC Se onan ie a beets eee ta eee tg hak abet elt e!-5 AM UREA OS GG ute nen yhale 5 INP ed OTUASOUYSHOr Sarl Bagg he tebe ep ue Neg May cart EEF Me Shea gece ese a ten oe dete ER icy ol 8 TROMGSGMYS TCUCNA,, NEW SPECIES 6b eo ene ee A ee ee ee lee ees dena 10 Gi iUals Cas Sd DOn <1 08 Cola Bc 2 beset 0 MR |. aN CNN adh Renee REE LOE ot M20 7) Foie teers 2 aa Spee hel Ares re wi A: 14 EIS CUNS SION Phat tT AN crue SE dc cy OE Nhat ecclesia NTT Nhe Rates RIN A EOE R IE oo oath Ee NM Rass 35 SANE. Compl He SS eevee nil Bocce a weet teeeies ETe ll scopes svenmns a out Ue eee mh entero rUTe Ws op Rony 3D BiSgeserap iG Ge OmipyORNOR jo Be kee eo eterna ig eee Se hy tu belie Osho of Renae Rie egz Quy ie oe 36 Horizontal Complementarity: Comparisons with Other Highland Faunas ............ By) Vertical Complementarity: Comparisons with Adjacent Lowland Faunas ............ 38 The<Unknew ii Middle Eley atin: C4 cca! fie: Bote wei fc eee wore te os shy er tenes + etiparcta ec: oo oly tah 39 DTCC HGS fOr TUTOR CSE ARC Mr ice gigter test plat gh lene teks gn Fa? sy gets ey da he genes ees tehe e 40 CROW EU OINENiS: 80104 mot ak et Mil ie ni ee Ee eine Ade yas Rie aa ETE ele 40 [aed Fs Rad 11 oe Sea eR NC Se ae SO ATO tat ER eS RE SS ROS ALA Ch ot a tart ee CL ea 4] PD poiichixe |, Cre OCramlaic: NOLO Ge 0-0 roe neers santas estaba eats ar the oe eee Ae Ah 45 Appendix 2: Nonvolant Lowland Mammals from Napo and Sucumbios .............. 46
' Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History. e-mail: voss@amnh.org
Copyright © American Museum of Natural History 2003 ISSN 0003-0082
AMERICAN MUSEUM NOVITATES
ABSTRACT
A new species of the murid rodent genus Thomasomys is described from the Cordillera Oriental of eastern Ecuador, a major range of the northern Andes that remains almost com- pletely unexplored mammalogically. In order to provide a baseline for future faunal inventory work in these mountains, this report summarizes specimen data from the vicinity of Papallacta (0°22'S, 78°08'W), a small village located near tree line on the eastern (Amazonian) slope. In addition to the new Thomasomys, the local fauna includes 32 other species of nonvolant mammals, of which several (Akodon latebricola, Thomasomys cinnameus, and T. erro) have not been reported since their original descriptions in the 1920s. Taxonomic research based on this material indicates that at least six taxa currently treated as synonyms or subspecies should be recognized as valid species, including Thomasomys popayanus (possibly including T. ni- cefori) and T. praetor (both formerly synonymized with T. aureus), T. cinnameus and T. hudsoni (both formerly synonymized with T. gracilis), T. erro (formerly synonymized with T. cinereiventer), and Coendou quichua (formerly synonymized with C. bicolor). Although the Papallacta fauna includes several clades (“‘genera’’) that extend to south- and north-temperate latitudes, over half of the local species are endemic to the northern Andes (north of the Huancabamba Deflection in northern Peru); among these northern-Andean endemics, three species known only from northeastern Ecuador provide evidence for a distinct center of en- demism in the Cordillera Oriental. Quantitative estimates of species-level faunal complemen- tarity indicate substantial horizontal turnover (between ecologically similar highland sites) on the scale of a few hundred kilometers, and almost complete vertical turnover (between adjacent highland and lowland sites) on the scale of about 2000 m. Both phenomena pose significant challenges for timely inventory work across vast Andean landscapes that remain sparsely sampled by mammalogists. In particular, the middle elevations of the eastern slope of the northern Andes, a densely forested region approximately 2 km high and over 1500 km long,
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remain a mammalogical terra incognita.
INTRODUCTION
Although the Cordillera Oriental (eastern Andes) of Ecuador was first traversed by Eu- ropeans in the sixteenth century, scientific knowledge of mammals from this region was not forthcoming until the late 1800s, when a small number of specimens began to arrive in European museums (de Winton, 1896; Ca- brera, 1913, 1917). Throughout the first sev- eral decades of the 1900s, a period of active biological inventory elsewhere on the conti- nent, only scattered collections amounting to just a few dozen specimens were made in the Cordillera Oriental. To date, no regional spe- cies lists or faunal descriptions of any kind have been published. This dearth of infor- mation is explained by the fact that only a few primitive trails formerly crossed the rug- ged eastern Andean escarpment, and those that did were frequently closed by landslides and other accidents. Even today, when all- weather roads provide more-or-less reliable access along several routes, the Cordillera Oriental remains almost unexplored mam- malogically. Steep, unstable slopes afford few places to camp, and the dripping-wet
forests are miserable places to run traplines for more than a few days at a time. Most collecting expeditions to eastern Ecuador have hurried downslope to more inviting habitats in the Amazonian lowlands.
One of the few inhabited places in the Cordillera Oriental is Papallacta (0°22’S, 78°08'W), a small village perched several hundred meters below treeline on the eastern slope (fig. 1). Centuries old, and a regular stopping point along the ancient trail from Quito to Baeza, Papallacta was often visited by itinerant naturalists and collectors (e.g., Jameson, 1858; Almagro, 1866; Orton, 1870; Goodfellow, 1901; Sinclair, 1929; Moore, 1934; Webb, 1939). None, however, made substantial collections of mammals there, with the result that only a few species of the local fauna have been recorded in the liter- ature.
In the course of field research on ichthy- omyine rodents (Voss, 1988), I collected nonvolant small mammals near Papallacta on several visits from 1978 to 1980, including a new species belonging to the endemic An- dean muroid rodent genus Thomasomys.
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VOSS: NEW THOMASOMYS 3
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an location of map ECUADOR
Map of the Papallacta region (based on IGM, 1978a, 1978b) illustrating local landscape
features mentioned in the text. Both the north pass (crossed by the modern road from Quito to Baeza)
and the south pass (now roadless) are referred to in the literature as “‘Guamani
Per)
(see appendix 1). Two
nearby localities recorded on specimen tags are outside the limits of this quadrangle: Tabl6n lies about 3 km to the west, and Cerro Antisana is about 8 km to the south. The continental divide, which runs diagonally across the upper left corner, forms the boundary between Pichincha province (to the west)
and Napo province (to the east).
Herein I describe that species and summarize information about other sympatric taxa rep- resented among the material collected. These data, together with records of additional spe- cies documented by museum specimens or other reliable information, provide the basis for a preliminary assessment of mammalian diversity and biogeographic relationships on the upper slopes of the Cordillera Oriental. In effect, this study establishes a baseline for future inventory efforts along a still-intact but threatened habitat gradient that extends over 4000 m from snow line to the Amazo- nian lowlands and harbors one of the least known mammalian faunas in South America.
THE PAPALLACTA REGION
The mean annual temperature at Papallac- ta—ca. 3200 m above sea level—is almost 17°C (Wernstedt, 1972), but nights are cold throughout the year, mornings are always chilly, and only the rare sunny afternoon is actually warm. Above the town, temperatures are substantially lower. A maximum-mini- mum thermometer that I installed beneath the forest canopy at 3600 m and checked daily from 9 March to 14 April 1980 recorded a minimum temperature of 4°C and a maxi- mum temperature of 14°C during that inter- val. Ground frost is common on open hill-
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sides from about 3400 m upslope, where stream banks are often rimed with ice in the early morning. Blizzards occasionally blan- ket the landscape above 4000 m with snow, and local herders sometimes lose cattle to ex- posure in the months of invierno (the local winter, July and August). Permanent snow fields begin at about 4700 m on Cerro An- tisana, about 11 km due south of Papallacta (Whymper, 1892; Black, 1982).
Eleven years of weather records from Pa- pallacta indicate that local precipitation is seasonally distributed, with an average monthly minimum of 98 mm in December and an average monthly maximum of 215 mm in July; the total annual average is 1643 mm (Wernstedt, 1972). Although these fig- ures are not impressive by comparison with those from adjacent lowland sites that receive almost 4000 mm of rainfall annually (Fern- don, 1950), Papallacta is persistently humid because it is shrouded in fog and mist for most of the year. Chapman’s (1926: 29) in- explicable assignment of Papallacta to the ‘Arid Division”? of his so-called Temperate Zone was not based on first-hand experience of this notoriously damp region.’
Most of the mineral substrate surrounding Papallacta is igneous, consisting of lava, cin- ders, and ash from prehistoric eruptions of Antisana (0°30'S, 78°08’W; 5700 m), a now- dormant volcano that is one of the principal peaks of the Cordillera Oriental (see Sauer [1971: 16] for a brief technical account of the local geology). From the continental di- vide (about 4100 m; see appendix 1) to tree- line the local landscape consists of rolling hillsides and rocky peaks dissected by nar- row ravines or divided by broad flat-bot- tomed cirques (fig. 2). The alpine vegetation of this paramo zone consists principally of wiry bunch grass (to 1 m high) on well- drained slopes (fig. 3), but flat valley bottoms are marshy with pools of standing water and low hummocks of moss and other cushion-
? There is no indication in Chapman’s published Ecu- adorean itinerary (op. cit.: 15-16) that he ever visited Papallacta. Moore (1934: 99) did, however, and he cor- rectly assigned Papallacta to the “‘Humid Temperate Zone’ of Chapman’s ecogeographic system. Every trav- eller’s account mentions the cold and the wet near Pa- pallacta, but particularly evocative annecdotes are pro- vided by @llgaard and Balslev (1979: 17-28).
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forming plants. Large terrestrial bromeliads (Puya) are scattered on open hillsides, but other kinds of large rosette plants that are common in Colombian and Venezuelan pa- ramos are seldom seen. Almost pure stands of Polylepis (Rosaceae) occur as dense thick- ets whose canopies rarely exceeds 3—4 m. Within these nearly impenetrable tangles, limbs, trunks, and elevated root mats are cov- ered with thick layers of cold, wet moss. Ad- ditional floristic, phenological, and anthro- pogenic aspects of local paramo habitats are described by Grubb (1960), @llgaard and Balslev (1979), Black (1982), and Laegaard (1992).
Between about 3700 and 3600 m, an eco- tone of mixed bunch grass and waist-high shrubs (fig. 4) marks the transition between open paramo vegetation and Subalpine Rain Forest (sensu Grubb, 1977), a distinctive for- mation of small trees that marks the upper- most limit of continuous forest cover. The canopy of this dwarfed forest seldom ex- ceeds 5 or 6 m. There is no appreciable un- derstory vegetation, but horizontal limbs, sprawling trunks, and fallen logs limit foot travel and visibility. Although epiphytic or- chids and bromeliads seem to be absent at this elevation, wet mats of moss, lichens, and climbing ferns completely cover tree trunks and branches (fig. 5). A few thin vines are present, but not woody lianas. Palms, bam- boo, and tree ferns are likewise absent. Her- baceous dicots, ferns, and horsetails (Equi- setum) provide a sparse ground cover. Moss, littered leaves, matted roots, and a deep, peaty humus make the ground soft and springy underfoot.
Below about 3400 m, the forest becomes gradually taller and assumes the characteris- tics of Upper Montane Rain Forest (sensu Grubb, 1977), but in the immediate vicinity of Papallacta (between about 3200 and 3000 m) most of this natural vegetation has been cleared for agriculture and animal husband- ry; only a few stands of dense secondary growth persist along streambanks, at the ba- ses of cliffs, and at the bottoms of steep ra- vines. Farther downslope, the forest canopy ascends to 25 m or more, vascular epiphytes (e.g., orchids and bromeliads) are conspicu- ous on tree trunks and branches, and tree ferns and bamboo (Chusquea) are abundant
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res
VOSS: NEW THOMASOMYS é,
oe ie : - ~
Fig. 2. Paramo landscape about 12 km (by road) W Papallacta. The road from Quito to Baeza crosses the middle foreground approximately following the 3900 m contour. The open (paler) vegetation is paramo grassland, whereas the darker patches are Polylepis thickets. Photographed by Paul Kaarakka,
14 April 1980.
in the understory. Other vegetation forma- tions along this elevational gradient (Lower Montane Rain Forest at 1710 m and Lowland Rain Forest at 380 m) were described in de- tail by Grubb et al. (1963).
MATERIALS AND METHODS
I worked near Papallacta in May and June of 1978 and in March, April, May, and Au- gust of 1980. Traplines were laid out to sam- ple all local habitats as thoroughly as possi- ble, but a special effort was made to collect semiaquatic species by wading in streams and setting traps along the water’s edge. For- est traplines always consisted of traps set both in trees and on the ground. Except as noted below I used only snap-traps (Museum Specials and Victor rat traps), which were baited with rolled oats mixed with either canned sardines or peanut butter.
All trapped mammals were prepared as
skins and skulls (with skinned carcasses in 10% formalin), or were preserved entire in 10% formalin; formalin-preserved material was subsequently washed and transferred to 70% ethanol for museum storage. Standard external measurements in millimeters (total length from nose to fleshy tail tip, TL; length of tail from dorsal flexure to fleshy tip, LT; length of hindfoot from heel to longest claw, HF; and length of ear from notch to fleshy apex, Ear) and weight in grams were record- ed along with habitat notes (see below) and other information in field catalogs that are currently stored as bound volumes in the Di- vision of Mammals at the University of Michigan Museum of Zoology (UMMZ). Habitat and microhabitat data were record- ed in a waterproof notebook at each capture site. In 1980 all trapped animals were placed individually in small paper bags with a chlo- roform-soaked gauze pad, and the bag was
6 AMERICAN MUSEUM NOVITATES
RISA
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Closeup of paramo vegetation at 3800 m above sea level, approximately 11 km (by road)
W Papallacta. Wiry bunch grass (foreground) is the typical vegetation on exposed slopes at this ele- vation, but Polylepis thickets occur on the hill crest and backslope. Photographed by Paul Kaarakka, 19
April 1980.
then twisted shut; each specimen was sub- sequently combed for ectoparasites, which were preserved in 70% ethanol. All mam- malian specimens were given unique field catalog numbers (prefixed by ““RSV’’), and the same numbers were used to identify the hosts of collected ectoparasites (e.g., the ho- lotype of Plocopsylla nungui Schramm and Lewis, 1987).
Mileages provided in the text were mea- sured from the center of Papallacta by auto- mobile odometer, or were estimated from a 1:25,000 topographic map (IGM, 1978). Al- titudes were recorded in the field using a Thommen 2000 pocket altimeter calibrated in feet (ft). Fifteen altimetric readings that I recorded from this instrument in the center of Papallacta from 2 March to 14 April 1980 had a mean of 10,266 ft, a standard deviation of 44 ft, and a range of 10,180—10,325 ft; according to the best available topographic map (IGM, 1978), the elevation in the center
of Papallacta is 3160 m (10,367 ft), suggest- ing that the altimetric data reported herein are about 30 m less, on average, than corre- sponding map values. In the following ac- counts, elevations that I originally recorded in feet are converted to their metric equiva- lents.
Most of the systematic problems discussed below concern muroid rodents, for which rel- evant anatomical terminology is referenced or defined by Reig (1977), Carleton (1980), and Voss (1988, 1993). Head-and-Body Length (HBL) was obtained from measure- ments taken in the field (see above) by sub- tracting Length of Tail (LT) from Total Length (TL). The following craniodental measurements were taken in the museum with dial calipers (fig. 6): CIL, condylo-in- cisive length; LD, length of diastema; LM, occlusal length of the maxillary molar row; BM1, breadth of the first maxillary molar; LIE length of one incisive foramen; BIE
2003 VOSS: NEW THOMASOMYS vi
Fig. 4. The shrubby ecotone at treeline (about 3700 m above sea level) where most specimens of the new Thomasomys species were collected, approximately 8 km (by road) W Papallacta. Photographed
by the author, 12 May 1978.
breadth across both incisive foramina; BPB, breadth of the palatal bridge; BZP, breadth of the zygomatic plate; LIB, least interorbital breadth; ZB, zygomatic breadth; DI, depth of upper incisor; BIT, breadth across both upper incisor tips.
The specimens reported below are depos- ited in the following institutional collections, listed in order of their traditional acronyms: The American Museum of Natural History, New York (AMNH); the Natural History Museum, London (BMNH); the Field Mu-
8 AMERICAN MUSEUM NOVITATES NO. 3421
ae ? r Ps are . fs a J 4 Poe a
Fig. 5.
seum of Natural History, Chicago (FMNH); the University of Kansas Museum of Natural History, Lawrence (KU); the Museo Argen- tino de Ciencias Naturales “‘Bernardino Ri- vadavia’’, Buenos Aires (MACN); the Mu- seo de Ciencias Naturales, Instituto Nacional Mejia, Quito (MCN); the Museum of Com- parative Zoology, Harvard University, Cam- bridge (MCZ); the Museo Nacional de Cien- cias Naturales, Madrid (MNCN); the Muse- um, Michigan State University (MSU); the Museum of Vertebrate Zoology, Berkeley (MVZ); Museo de Zoologia, Pontifica Univ- ersidad Catélica del Ecuador (QCAZ); the Natural Historie Riksmuseet, Stockholm (NHRS); the University of Michigan Muse- um of Natural History, Ann Arbor (UMMZ); and the National Museum of Natural History, Washington (USNM). A representative series of the Papallacta material currently cataloged in the UMMZ collection will be transferred to QCAZ in the near future to serve as an
mee
ge
PO as - > Subalpine Rain Forest just below treeline (about 3600 m above sea level), approximately 6 km (by road) W Papallacta. The low, tangled structure of the forest and the thick mats of moss, lichens,
and climbing ferns that cover trunks and branches are characteristic features of this habitat. Photographed by Paul Kaarakka, 16 April 1980.
in-country resource for specimen identifica- tion.
A NEW THOMASOMYS
Among the material collected near Papal- lacta is a previously unknown murid rodent belonging to the sigmodontine genus Tho- masomys Coues. Formerly construed broadly to include southeastern Brazilian taxa (e.g., by Osgood, 1933; Ellerman, 1940; Cabrera, 1961; Pine, 1980), Thomasomys has subse- quently been restricted (Voss, 1993; Gonza- lez, 2000) to a smaller but still speciose group that is endemic to tropical Andean cloud forests from Venezuela to Bolivia. Ap- parently, the center of diversity for the genus includes eastern Ecuador, where the new spe- cies described below may occur sympatrical- ly with at least seven other congeners.
2003 VOSS: NEW THOMASOMYS 9
Fig. 6. Anatomical limits of 12 rodent craniodental measurements described in the text (see Materials and Methods).
10 AMERICAN MUSEUM NOVITATES
Thomasomys ucucha, new species Figures 7—13
TYPE MATERIAL: The holotype, UMMZ 155644 (skin, skull, and fluid-preserved car- cass; original number RSV 660), is an adult male that I collected on 26 April 1980 at an elevation of 11,100 ft (3384 m) in the valley of the Rio Papallacta (ca. 3—5 km by trail NNW Papallacta), Provincia Napo, Ecuador.
Forty-two other specimens collected in 1978 and 1980, hereby designated as para- types, are from 8.2 km (by road) W Papal- lacta, 12,200 ft (UMMZ 127119, 127120, 155717); 7.5 km (by road) W Papallacta, 12,000 ft CUMMZ 155652—155655, 155722— 155732); 6.2 km (by road) W Papallacta, 11,700 ft (AMNH 24461 1-—244613; UMMZ 127121, 155742, 155649-155651, 155714— £53 7 1G. LSSHLS, VSST U9, n1597 3551055 736)5 and the Rio Papallacta valley [3-5 km by trail NNW Papallacta], 11,100 ft (UMMZ 155643, 155645—155648, 155720, 155721). Three additional paratypes (AMNH 46621, 46622, 46624) were collected in 1903 by L. S6derstr6m at Tabl6n, in Provincia Pichincha (see appendix 1).
DISTRIBUTION: Known only from the crest of the Cordillera Oriental (between ca. 3400 and 3700 m) just south of the equator in the Ecuadorean provinces of Pichincha and Napo.
EtryMo.Locy: Ucucha is the local Quichua word for “‘mouse”’ (Orr, 1978), here treated as a noun standing in aposition to the generic name.
DIAGNOsIs: A medium-sized, dark-furred, long-tailed species of Thomasomys with short, blunt rostrum; narrow interorbital re- gion with rounded supraorbital margins; widely flaring zygomatic arches; straight fronto-nasal profile; broad, vertically orient- ed zygomatic plate; short incisive foramina; separate buccinator-masticatory and acces- sory oval foramina; primitive (pattern 1) ca- rotid circulation; small, uninflated auditory bullae; small, hypsodont molars lacking well-developed cingula and stylar cusps; very small upper third molars; broad and conspicuously procumbent upper incisors; and a distinctive range of morphometric var- iation (table 1).
DESCRIPTION: Pelage dense, fine, and soft,
TABLE 1
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Measurements (mm) and Weights (g) of Thomasomys ucucha and T. hylophilus*
T. ucucha
T. hylophilus*
Sex 19 females, 17 males 10 females, 14 males HBL 110 + 6 (94-119) 35 115 + 5 (107-125) 24 LT 140 + 7 (122-151) 35 142 + 7 (124-155) 24 HF 28 + 1 (26-30) 35 26 + 1 (25-28) 24 Ear 18 + 1 (17-20) 35 18 + 1 (17-20) 11 CIL 27.8 + 0.9 (25.8-29.1) 36 26.9 + 0.9 (25.2-28.9) 21 LD 8.9 + 0.4 (7.9-9.6) 36 8.0 + 0.4 (7.2-8.6) 24 LM 4.4 + 0.1 (4.24.6) 32 4.8 + 0.2 (4.5-5.2) 24 BMI 1.4 + 0.0(1.4-1.5) 36 1.5 + 0.0 (1.4-1.5) 24 LIF 54 + 0.2 (4.9-5.8) 36 6.1 + 0.3 (5.4-6.7) 24 BIF 2.3 + 0.1 (2.0-2.5) 36 2.3 + 0.2 (1.9-2.6) 22 BPB 3.6 + 0.2 (3.34.0) 36 3.3 + 0.2 (3.0-3.8) 22 BZP 2.4 + 0.1 (2.1-2.6) 36 2.4 + 0.1 (2.2-2.7) 24 LIB 4.8 + 0.1 (45-49) 36 4.7 + 0.1 (45-49) 23
ZB 15.9 = 0.6 (14.4~16.8) 36 15.6 + 0.5 (14.6-16.4) 22
DI 1.5 + 0.1 (1.3-1.6) 36 1.5 = 0.1 (1.3-1.7) 24 BIT 2.1 + 0.2 (1.6-2.3) 36 1.9 + 0.1 (1.7-2.1) 24 Weight 36 + 5 (2446) 35 36 + 3 (32-40) 11
4Tabulated statistics for both species include the mean plus or minus one standard deviation, the observed range (in paren- theses), and the sample size.
bAMNH 24461 1-244613; UMMZ 127119-127121, 155643, 155644, 155646, 155649, 155651-155655, 155714, 155716, 155717, 155719, 155722-155726, 155728—155732, 155734, 155735, 155742, 155745, 155720, 155721, 155727.
CAMNH 143667, 143608; FMNH 18563, 18565, 18566, 18576, 18580, 18584, 18587, 18591, 18593, 18595; USNM 259613, 442305, 442308, 442313, 442315-442320, 442322, 442324.
about 13-15 mm long over the back and rump; somberly colored (dark) and not abruptly countershaded. Mass-effect dorsal coloration near Smithe’s (1975) Brownish Olive (color 29) along flanks, shading to Dark Grayish Brown (color 20) middorsally. Ventral pelage Dark Neutral Gray (color 83) basally, with superficial wash of Light Neu- tral Gray (color 85) or Glaucous (color 80); not sharply set off from dorsal coloration. Mystacial vibrissae long, extending just be- hind pinnae when laid back alongside head. Ears sparsely covered with short, blackish hairs, not contrasting conspicuously with col-
2003
or of head. Hairs over metapodials and digits of manus and pes dark, but tufts of longer hairs at bases of pedal claws silvery. Pes nei- ther very narrow nor conspicuously broad; digit V long (its claw extending almost to base of claw of digit IV), but apparently non- opposable. Tail substantially longer than combined length of head and body, uniform- ly dark in most specimens but occasionally tipped with white; sparsely haired except for 5—10 mm terminal pencil. Mammae six in inguinal, abdominal, and postaxial pairs. Skull Gin dorsal view) characterized by short, blunt rostrum flanked by shallow zy- gomatic notches; narrow, hourglass-shaped interorbit with rounded (not beaded or squared) margins; broadly flaring zygomatic arches; and large, oblong braincase un- marked by prominent temporal scars or lambdoidal ridges. Dorsal profile (in lateral view) distinctively flattened from nasal tips to midfrontal region; anterior margin of zy- gomatic plate straight and nearly vertical, not conspicuously sloping backward from base. Incisive foramina widest just behind premax- ilary/maxillary suture and short (averaging 60% of diastemal length), not approaching first molar alveoli. Palatal bridge broad, smooth (without prominent ridges or grooves), and short (not extending posteri- orly behind molar rows); posterolateral pits small, simple, inconspicuous perforations (never large, complex, or recessed in shallow fossae). Mesopterygoid fossa broad, straight- sided, extending anteriorly between third molars; bony roof complete or perforated by narrow, slit-like sphenopalatine openings flanking the presphenoid/basisphenoid su- ture. Parapterygoid fossae narrow, approxi- mately triangular, with shallow (unexcavat- ed) anterior limits. Alisphenoid strut present, separating buccinator-masticatory from ac- cessory oval foramina. Carotid circulation primitive (pattern 1), as indicated by large stapedial foramen, prominent squamosal-ali- sphenoid groove, and sphenofrontal foramen. Postglenoid foramen and subsquamosal fe- nestra subequal; tegmen tympani broadly overlaps posterior suspensory process of squamosal. Auditory bullae small, uninflated, flask-shaped; without sharply defined transi- tion between capsular part and bony eusta- cian tube. Tympanic membrane pars flaccida
VOSS: NEW THOMASOMYS J
present, large. Malleus with large orbicular apophysis.
Mandible with distinct capsular process for lower incisor alveolus on lateral surface posteroventral to base of coronoid process. Basihyal more-or-less straight (not strongly arched), without entoglossal process.
Upper incisors large, broad, and conspic- uously procumbent, with heavily pigmented enamel bands (near Smithe’s [1975] Spec- trum Orange [color 17] in fresh material). Upper molars in parallel left and right series, small, pentalophodont, hypsodont when un- worn (by comparison with more brachydont congeners), and lacking well-developed cin- gula and stylar cusps. M1 anterocone divided by anteromedian flexus into subequal anter- olabial and anterolingual conules. Paralophs and metalophs (on M1 and M2) connect cor- responding labial cusps to mesolophs and posterolophs, respectively, or to median mures, not to opposing lingual cusps. M3 conspicuously smaller than M2 (<50% as es- timated by occlusal areas) and usually lack- ing a distinct lingual fold (hypoflexus). Low- er molars similar to upper teeth in general design, but ml anteroconid often undivided (even in unworn dentitions), and m3 not con- spicuously reduced. Molar root formulas un- known (no specimens are available with loose teeth), but M1 and m1 apparently with- out accessory rootlets.
Stomach unilocular-hemiglandular. Adult males with one pair each of dorsal prostate, anterior prostate, ampullary, vesicular, and bulbo-urethral glands; and with two pairs of ventral prostate glands. Macroscopic prepu- tial glands absent. Glans penis small, short, and subcylindrical (weakly divided into right and left halves by a shallow middorsal trough and an inconspicuous midventral raphe but otherwise unmarked by external folds); ex- ternally covered with coarse spines except for broad rim of soft, crenulated tissue sur- rounding terminal crater; crater contents in- clude three bacular mounds, bifurcate ure- thral flap, and one dorsal papilla; two small spinous patches of rugose epithelium present dorsolateral to bacular mounds, but remain- ing crater contents unarmed.
COMPARISONS: As restricted by Voss (1993) and Gonzalez (2000), the genus Tho- masomys consists of 6-mammate pentalopho-
12 AMERICAN MUSEUM NOVITATES
NO. 3421
Fig. 7. Dorsal, ventral, and lateral cranial views of Thomasomys ucucha (left, UMMZ 155644, holotype) and 7. hylophilus (right, FMNH 18593, paratype). Approximately twice life size.
dont Andean sigmodontines with very shal- low zygomatic notches; hourglass-shaped in- terorbital regions that lack well-developed beads or projecting supraorbital shelves; short palates lacking prominent posterolat- eral pits; and auditory bullae firmly attached to the skull by overlap of the tegmen tympani with a posterior suspensory process of the squamosal. Because all of these traits are cur- rently thought to be plesiomorphies within the Neotropical muroid radiation (Voss, 1993), the genus lacks compelling evidence of monophyly. Pending a comprehensive phylogenetic analysis of the “‘thomasomyi- ne’’ group, however, there is no more re- stricted taxonomic category within which to assess the relationships of 7. ucucha. Phe- netically, the new species most closely re- sembles 7. hylophilus Osgood (1912), an al-
lopatric taxon that occurs in northeastern Co- lombia and western Venezuela.* Thomasomys ucucha and T. hylophilus overlap in all external and craniodental mea- surements (table 1), and they share many qualitative traits in common: both lack genal vibrissae but have moderately long mystacial hairs; relatively long tails; similarly propor- tioned hind feet; flattened fronto-nasal pro- files; narrow interorbital regions with round-
3 Specimens of Thomasomys hylophilus examined for this report include the holotype (FMNH 18583) together with 43 other specimens collected in or near the Paramo de Tama on the border between Venezuela (Estado Tach- ira) and Colombia (Departamento Norte de Santander): AMNH 143667, 143668; FMNH 18563, 18565, 18566, 18576, 18580, 18584, 18587, 18591, 18593, 18595; USNM 259613, 442305, 442307-442311, 442313- 442320, 442322—442331, 442336—-442341.
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Fig. 8. Lateral mandibular views of Thoma- somys ucucha (A, UMMZ 155644, holotype) and T. hylophilus (B, FMNH_ 18593, paratype). Among other species differences, a distinct cap- sular process for the lower incisor alveolus is pre- sent posteroventral to the coronoid process in T. ucucha (arrow), whereas this structure is absent in 7. hylophilus.
ed supraorbital margins; straight, vertically oriented zygomatic plates; broad palates; ali- sphenoid struts that separate buccinator-mas- ticatory and accessory oval foramina; com- plete (pattern 1) carotid arterial circulations; oblong braincases; small, uninflated auditory bullae; relatively hypsodont molars that lack well developed cingula and stylar cusps; and unilocular-hemiglandular stomachs. Despite this suite of resemblances, ucucha and hy- lophilus differ in other points of comparison.
In dorsal cranial view (fig. 7), Thomaso- mys ucucha is distinguishable at a glance by its relatively short, broad rostrum and by its widely flaring, rounded zygomatic arches. By contrast, the rostrum of T. hylophilus is pro- portionately longer and narrower, and the zy- gomatic arches converge anteriorly from a widest point across their squamosal roots. In ventral view, the incisive foramina of ucucha are absolutely shorter than those of hylophi- lus, and they are also proportionately shorter in relation to the diastema: the ratio LIF/LD averages about 61% in the former species versus about 76% in the latter. The posterior opening of the alisphenoid canal, a tiny per-
VOSS: NEW THOMASOMYS 13
foration behind each parapterygoid fossa in ucucha, is a conspicuously larger orifice in hylophilus.
Thomasomys ucucha and T. hylophilus are also dentally distinctive. The upper incisors of ucucha are broader, more deeply pig- mented, and more procumbent than those of hylophilus. In side-by-side comparisons, the contrast in upper incisor procumbency be- tween the two species is visually obvious (fig. 7), but measurements provide a more objective basis for discrimination. Measured with an ocular goniometer, the chord that subtends the exposed greater curvature of these teeth defines an average anterior angle of 87° with the occlusal plane of the upper molars in ucucha (observed range, 85—89°; N = 14), whereas the homologous angle has an average value of 77° in hylophilus (ob- served range, 76—79°; N = 11).* A correlated species difference in the lower incisors is likewise apparent: whereas the lower incisor root of ucucha is contained in a prominent capsular process on the lateral mandibular surface just below the base of the coronoid process (fig. 8A), the lower incisor root of hylophilus terminates in an inconspicuous bony ridge without a distinct process (fig. 8B).
The molar dentition provides several ad- ditional traits of diagnostic value. The upper toothrow is shorter on average in Thomaso- mys ucucha than in T. hylophilus (table 1), a difference that is primarily attributable to the size of M3. That tooth ranges from 0.8 to 1.0 mm long and accounts for just 21% of av- erage toothrow length in ucucha, versus 1.2— 1.3 mm long and 25% of toothrow length in hylophilus. Correlated species differences in occlusal complexity are also apparent (fig. 9). In the upper molars, the anterolophs and mesolophs of M1 and M2 are much more weakly developed in ucucha than in hylo- Philus, and M3 usually lacks a distinct lin-
4This angle is equivalent to the incisive index of Thomas (1919), who defined the standard descriptive terminology for rodent incisor procumbency. According to Thomas’s definitions, proodont incisors are those with index values >90°, orthodont incisors are those with in- dex values close to 90°, and opisthodont incisors are those with index values <90°. Therefore, the incisors of Thomasomys ucucha are orthodont, whereas those of T. hylophilus are opisthodont.
14 AMERICAN MUSEUM NOVITATES
Fig. 9.
NO. 3421
Left upper and right lower molars of Thomasomys ucucha (left-hand photo of each pair,
UMMZ 155722) and T. hylophilus (right-hand photo of each pair, USNM 442322). Note the relatively smaller M3 of T. ucucha, the presence of a distinct lingual fold on the M3 of 7. hylophilus, and the relatively larger (more robust) anterolophs and mesolophs of the latter species.
gual fold (hypoflexus) in ucucha that is con- sistently present in hylophilus. In the lower dention, the anteromedian flexid of m1 is shallower, less persistent with wear, or alto- gether absent in ucucha, whereas this fold is always present and usually persistent in hy- lophilus.
Incisor procumbency alone is sufficient to set Thomasomys ucucha apart from other con- geners, only two of which approach the or- thodont condition (defined in footnote 4, above). However, both of those species—T. australis with an index value of 85°, and T. daphne with an index value of 90°—have chisel-like incisors that are much shorter and narrower than the more scooplike, longer, and broader teeth of ucucha (fig. 10), and neither species closely resembles ucucha in other re- spects. Thomasomys ucucha is readily distin- guished from other congeneric species known
to occur in the Cordillera Oriental of northern Ecuador (T. aureus, T. baeops, T. cinnameus, T. erro, T. paramorum, T. rhoadsi, T. silves- tris; see below) by numerous qualitative and quantitative character differences that are summarized in table 2.
REMARKS: In a previous list of Papallacta mammals (Voss, 1988: table 43), I referred to this taxon as ’ Thomasomys sp.”
FIELD OBSERVATIONS: The 42 specimens of Thomasomys ucucha that I collected near Pa- pallacta in 1978 and 1980 were trapped at elevations ranging from 3380 to 3720 m. Of these, 3 were taken in grassy paramo, 22 were taken in the shrubby paéramo/forest eco- tone or in grassy glades surrounded by forest, and 17 were taken deep inside Subalpine Rain Forest. Most recorded captures were on the ground, of which 18 were in rabbit trails or runways through dense grass or low herbs;
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VOSS: NEW THOMASOMYS {Be
Fig. 10. Lateral view of rostrum of Thomasomys ucucha (A, UMMZ 155652) and T. daphne (B, UMMZ 160579). Although both species have procumbent (orthodont) incisors, those of ucucha are longer, broader, and more scoop-like than the shorter, narrower, chisel-like teeth of daphne.
16 were in runways through moss or damp litter, under mossy debris, or at the bases of mossy trees; and 7 were along the wet mar- gins of small streams. Only one specimen was trapped off the ground, on the mossy limb of a low tree. Other muroid species that were trapped syntopically (in the same hab- itats) with 7. ucucha include Akodon late- bricola, Akodon mollis, Anotomys leander, Chilomys instans, Microryzomys altissimus, M. minutus, Neusticomys monticolus, T. au- reus, T. baeops, T. cinnameus, T. erro, and T. paramorum.
OTHER SYMPATRIC TAXA
In addition to Thomasomys ucucha, 32 other species of nonvolant mammals are def- initely known to occur along the crest of the Cordillera Oriental near Papallacta, including some that I collected in 1978 and 1980, oth- ers that were previously reported in the lit- erature, and a few that are here documented for the first time based on earlier collections. The geographic scope of the following re- view includes localities above 3000 m on both the western slope (Provincia Pichincha) and the eastern slope (Provincia Napo) from about 0°20'S to 0°30'S. The two most distant collection sites within these limits are only about 15 airline km apart.
The species accounts below summarize in- formation about available specimens from
this region, together with notes on taxonomy, habitats, and relevant literature references. Identifications of Thomasomys species were a significant challenge in working up this material due to the virtually complete ab- sence of any modern revisionary literature on this large and difficult genus (the unique ex- ception is G6mez-Laverde et al., 1997). In the absence of other taxonomic resources, I compared specimens with holotypes and/or original descriptions of all of the 40 nominal taxa listed by Musser and Carleton (1993), together with the recently described species T. apeco Leo and Gardner (1993), T. macro- tis Gardner and Romo (1993), and T. onkiro Luna and Pacheco (2002). In some cases the results of such exercises indicated that the current nomenclature is incorrect, and these accounts therefore recommend several nec- essary taxonomic changes.
Caenolestes fuliginosus (Tomes)
SPECIMENS COLLECTED: 10.6 km (by road) W Papallacta, 12,600 ft (UMMZ 155581); 6.2 km (by road) W Papallacta, 11,700 ft (AMNH 248261—248271; UMMZ 127107— 127109, 127152—127157, 155571—155580, 155688—155689, 155692—155695); Rio Pa- pallacta Valley, 11,100 ft (UMMZ 155570, 155690, 155691).
OTHER MATERIAL: Three additional speci-
16
T. aureus
AMERICAN MUSEUM NOVITATES
TABLE 2 Morphological Comparisons Among Eight Species of Thomasomys from the Cordillera Oriental
T. baeops
Size: large (HF = 38-40 mm; LM = 7.2-7.7 mm; weight 75-100+ g).
Tail relatively long (LT about 130% of HBL).
Dorsal pelage uniformly rich yellowish- to reddish- brown.
Genal vibrissae present.
Mystacial vibrissae very long, extending posteriorly well behind pinnae.
Rostral tube absent. Interorbital region very narrow,> with squared supraorbital margins. Zygomatic plate broad.° Incisive foramina very long, usually extending posteriorly between molar alveoli.
Palate narrow.4
Alisphenoid strut present.
Carotid circulation pattern 3.
Auditory bullae small and uninflated
Capsular process of lower incisor alveolus indistinct or absent.
Upper incisors opisthodont, not procumbent.
Molars fgasoabne when unworn; without well- developed cingulae
or stylar cusps.
Size: medium (HF = 24-27 mm; LM = 4.2-4.5 mm; weight 27-45 g).
Tail relatively long (LT about 126% of HBL).
Dorsal pelage dull olive- brown, darker middorsally than along flanks.
Genal vibrissae absent.
Mystacial vibrissae very long, extending posteriorly well behind pinnae.
Rostral tube absent.® Interorbital region narrow, with squared supraorbital margins.
Zygomatic plate broad.° Incisive foramina long, usually extending posteriorly to but not between molar alveoli.
Palate broad.4
Alisphenoid strut present.
Carotid circulation pattern 3.
Auditory bullae small and uninflated
Capsular process of lower incisor alveolus large well developed.
Upper incisors opisthodont, not procumbent.
Molars brachydont, even when unworn; with well- developed cingulae
and stylar cusps.
NO. 3421
T. cinnameus
&T. erro
Size: small (HF = 21-23 mm; LM = 3.8-4.0 mm; weight 14-19 g).
Tail relatively long (LT about 140% of HBL).
Dorsal pelage uniformly warm reddish-brown.
Genal vibrissae absent.
Mystacial vibrissae long, extending posteriorly just behind pinnae.
Rostral tube absent.4 Interorbital region narrow,” with rounded supraorbital margins.
Zygomatic plate broad.¢ Incisive foramina long, usually extending posteriorly to but not between molar alveoli.
Palate broad.4
Alisphenoid strut present.
Carotid circulation pattern 1.
Auditory bullae small and uninflated
Capsular process of lower incisor alveolus indistinct or absent.
Upper incisors opisthodont, not procumbent.
Molars hypsodont when unworn; without well- developed cingulae
or stylar cusps.
4 Character defined by Voss (1993: 15). b Expressed as a percentage of zygomatic breadth, relative interorbital breadth ranges from 25 to 39% among these species. Qualitative descriptors (“narrow”, “broad”, etc.) are arbitrary partitions of this continuum.
Size: medium (HF = 28-32 mm; LM = 4.5-4.8 mm; weight 28-46 g).
Tail relatively long (LT about 132% of HBL).
Dorsal pelage uniformly dark grayish-brown.
Genal vibrissae absent.
Mystacial vibrissae short, usually not extending posteriorly behind pinnae.
Rostral tube present.*
Interorbital region very broad, with rounded supraorbital margins.
Zygomatic plate narrow.<
Incisive foramina short, usually not extending posteriorly to molar alveoli.
Palate broad.4
Alisphenoid strut usually absent.
Carotid circulation pattern 1.
Auditory bullae small and uninflated
Capsular process of lower incisor alveolus absent.
Upper incisors opisthodont, not procumbent.
Molars hypsodont when unworn, without well- developed cingulae
or stylar cusps.
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T. paramorum
Size: small (HF = 23-25 mm; LM = 3.8-4.3 mm; weight = 17-26 g).
Tail relatively long (LT about 132% of HBL).
Dorsal pelage uniformly dull olive-brown.
Genal vibrissae absent. Mystacial vibrissae long, extending posteriorly just behind pinnae.
Rostral tube absent.® Interorbital region narrow,> with rounded supraorbital margins.
Zygomatic plate broad.© Incisive foramina very long, usually extending posteriorly between molar alveoli.
Palate broad.4
Alisphenoid strut present.
Carotid circulation pattern 1.
Auditory bullae large and conspicuously inflated.
Capsular process of lower incisor alveolus indistinct or absent.
Upper incisors opisthodont, not procumbent.
Molars hypsodont when unworn; without well- developed cingulae or stylar cusps.
VOSS: NEW THOMASOMYS
TABLE 2 (Continued)
T. rhoadsi
Size: medium (HF = 28-31 mm; LM = 5.1-5.6 mm; no weight data).
Tail relatively short (LT about 95% of HBL).
Dorsal pelage uniformly dark grayish-brown.
Genal vibrissae absent. Mystacial vibrissae short, usually not extending posteriorly behind pinnae. Rostral tube absent.4 Interorbital region broad,» with rounded supraorbital margins.
Zygomatic plate broad.° Incisive foramina short, usually not extending posteriorly to
molar alveoli.
Palate broad.4
Alisphenoid strut present.
Carotid circulation pattern 1.
Auditory bullae small and uninflated.
Capsular process of lower incisor alveolus indistinct or absent.
Upper incisors opisthodont, not procumbent.
Molars hypsodont when unworn; without well- developed cingulae or stylar cusps.
17
T. silvestris
T. ucucha
Size: medium (HF = 28-30 mm; LM = 4.8-5.1 mm; no weight data).
Tail relatively long (LT about 140% of HBL).
Dorsal pelage uniformly dark grayish brown.
Genal vibrissae absent. Mystacial vibrissae long, extending posteriorly just behind pinnae.
Rostral tube absent.* Interorbital region narrow,> with rounded supraorbital margins.
Zygomatic plate broad.° Incisive foramina short, usually not extending posteriorly between molar alveoli.
Palate broad.4
Alisphenoid strut present.
Carotid circulation pattern 1.
Auditory bullae small and uninflated.
Capsular process of lower incisor alveolus indistinct or absent.
Upper incisors opisthodont, not procumbent.
Molars hypsodont when unworn; without well- developed cingulae or stylar cusps.
Size: medium (HF = 26-30 mm; LM = 4.2-4.6 mm; weight = 24-46 g).
Tail relatively long (LT about 128% of HBL).
Dorsal pelage uniformly dark grayish-brown.
Genal vibrissae absent. Mystacial vibrissae long, extending posteriorly just behind pinnae.
Rostral tube absent.4 Interorbital region narrow,» with rounded supraorbital margins.
Zygomatic plate broad.° Incisive foramina very short, not approaching level of molar alveoli.
Palate broad.4
Alisphenoid strut present.
Carotid circulation pattern 1.
Auditory bullae small and uninflated.
Capsular process of lower incisor alveolus usually distinct.
Upper incisors orthodont, conspicuously procumbent.
Molars hypsodont when unworn; without well- developed cingulae or stylar cusps.
¢ Expressed as a proportion of condylo-incisive length, the relative breadth of the zygomatic plate ranges from 5 to 9% among these species. Qualitative descriptors (“narrow”, “broad”, etc.) are arbitrary partitions of this continuum. 4 Character defined by Hershkovitz (1962: 54).
18 AMERICAN MUSEUM NOVITATES
mens (FMNH 43164-43166) were collected on Cerro Antisana by R. Olalla in 1930. TAXONOMY: The genus Caenolestes was revised by Bublitz (1987), who examined eight of the specimens listed above and iden- tified the local population as belonging to the nominotypical subspecies C. f. fuliginosus. FIELD OBSERVATIONS: The 40 specimens of Caenolestes fuliginosus that I collected near Papallacta in 1978 and 1980 were trapped at elevations ranging from 3380 to 3840 m. Of these, 39 were taken in Subalpine Rain For- est, and one was trapped in a Polylepis thick- et in the paramo zone. Most recorded cap- tures were on the ground: 24 along mossy or muddy stream margins, 5 in narrow runways or tunnels through wet moss, 5 in wet leaf litter beneath tangled shrubs or branches, and 3 in shallow cavities beneath earth banks or root mats. Only three individuals were taken above ground level, on the inclined trunks or horizontal limbs of low, moss-covered trees.
Didelphis pernigra J.A. Allen
SPECIMENS COLLECTED: 1.4 km (by road) E Papallacta, 9980 ft (UMMZ 155582).
OTHER MATERIAL: Apparently none.
TAXONOMY: The white-eared Neotropical Didelphis were recently revised by Lemos and Cerqueira (2002), who distinguished the Andean form (D. pernigra) as a distinct spe- cies from the predominantly lowland taxon D. albiventris Lund, with which it was for- merly synonymized (e.g., by Gardner, 1993).
FIELD OBSERVATIONS: The single specimen of Didelphis pernigra that I collected near Papallacta in 1980 was taken at 3040 m in a wire live trap set on the ground in wet sec- ondary growth surrounded by pastures and agricultural fields.
Cryptotis cf. montivagus (Anthony)
SPECIMENS COLLECTED: 7.5 km (by road) W Papallacta, 12,000 ft (UMMZ 155585); 6.2 km (by road) W Papallacta, 11,700 ft (UMMZ 155583, 155584, 155704, 155705).
OTHER MATERIAL: A single specimen (AMNH 63844) labeled “‘“Guamani’’ on one side of the original label and “‘Cerro Gua- mani” on the other side was collected by the Olallas in 1922. Additional shrews from the Cordillera Oriental include one (MCN 150)
NO. 3421
collected at Papallacta by C. Olalla in 1931 and another (QCAZ 307) collected on Anti- sana by R. Sierra in 1985 (D. Tirira, personal commun.).
TAXONOMY: The Ecuadorean species of Cryptotis were recently reviewed by Vivar et al. (1997), who identified the Guamani spec- imen (AMNH 63844) as C. montivagus. The five Papallacta shrews, collected only a few kilometers from Guamani, appear to be in- distinguishable from AMNH 63844 and pre- sumably represent the same taxon. However, measurements of these six specimens (from Papallacta and Guamanji) indicate that they have slightly narrower zygomatic plates and broader interorbits than typical montivagus, and side-by-side comparisons reveal that they have much less robust anterior unicus- pids than any specimen of the type series (AMNH 47197-47201; from Bestion, in the Ecuadorean province of Azuay). The possi- ble taxonomic significance of these and other differences (V. Pacheco and N. Woodman, personal commun.) remain to be determined by a more comprehensive evaluation of char- acter variation in Ecuadorean shrews.
REMARKS: In a previous list of Papallacta mammals (Voss, 1988: table 43), I misiden- tified this material as Cryptotis thomasi (Merriam, 1897).
FIELD OBSERVATIONS: The five shrews that I collected near Papallacta in 1980 were tak- en at elevations ranging from 3570 to 3660 m. Of these, three were trapped on the ground in runways or small tunnels through moss in Subalpine Rain Forest, one was found dead on a trail in Subalpine Rain For- est, and one was trapped in a runway though tall grass at the paramo/forest ecotone.
Pseudalopex culpaeus (Molina)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: I examined a single specimen (AMNH 66739) collected at 4145 m elevation on Cerro Antisana by G.H.H. Tate in 1923. Another specimen (MNCN 3652), which I have not seen, was collected on Antisana by M. Jiménez de la Espada in 1865 (J. Barreiro, personal commun.).
TAXONOMY: There has been no compre- hensive revision of the wolf-like canid taxa currently referred to this species. According
2003
to L6nnberg (1922) and Cabrera (1958) the local form is reissii Hilzheimer (1906), which was originally described from material collected on Volcan Cotopaxi (0°40’S, 78°26'W).
REMARKS: According to Emerson and Johnson (1960) and Black (1982), Pseudal- opex culpaeus is common in the paramo landscapes surrounding Cerro Antisana.
Lynchailurus pajeros (Desmarest)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: A single specimen (FMNH 43291) was collected by R. Olalla at 4000 m elevation on Cerro Antisana in 1934.
TAXONOMY: The pampas cat genus Lyn- chailurus was revised by Garcfa-Perea (1994), who examined FMNH 43291 and identified the local population as L. pajeros thomasi Lonnberg (1913). Wozencraft (1993) included this taxon in the synonymy of On- cifelis colocolo (Molina).
Puma concolor (Linnaeus)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: Apparently none.
REMARKS: Pumas are hunted along the crest of the Cordillera Oriental, where they are said to follow the movements of deer in remote parts of the paramo near Cerro An- tisana (Emerson and Johnson, 1960), but I did not observe any in the course of my work near Papallacta.
Conepatus cf. semistriatus (Boddaertt)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: I examined a single specimen (AMNH 66719) that was collected by H.E. Anthony at 4145 m on Cerro Anti- sana in 1923. Other material that I have not seen (Diego Tirira, personal commun.) in- cludes one specimen from 4200 m on Cerro Antisana (QCAZ 0638), and another from 2800 m near Cuyuja (E of Papallacta on the road to Baeza; QCAZ 0726).
TAXONOMY: Ecuadorean hog-nosed skunks are currently referred to Conepatus semis- triatus (e.g., by Cabrera, 1958; Kipp, 1965; Wozencraft, 1993), but no substantive anal- ysis of character data is apparently available
VOSS: NEW THOMASOMYS 19
to justify this convention.” Van Gelder’s (1968) detailed analysis of variation in cra- nial and pelage traits within a very large Uru- guayan sample of Conepatus could serve as the basis for a much-needed revision of this genus in South America.
REMARKS: Although none were seen in the course of our fieldwork, skunks are said to be common in local paramo habitats (Black, 1982).
Mustela frenata Lichtenstein
SPECIMENS COLLECTED: None.
OTHER MATERIAL: I examined two speci- mens from the Stockholm museum collected by L. Sdderstr6m in 1918. One (NHRS A58/ 6157) is an adult male labeled “‘side of Gua- mani near Papallacta 11,000 ft” [3353 ml], and the other (NHRS A58/6145) is an adult female labeled “‘below Papallacta 9000 ft”’ [2743 m]; both are skins and skulls in good condition.
TAXONOMY: LOnnberg (1921) and Hall (1951) examined the material described above and provided qualitative descriptions and measurements in their systematic ac- counts. However, whereas Loénnberg identi- fied the local population as Mustela macrura Taczanowski (1874), Hall treated macrura and other South American long-tailed wea- sels as subspecies of M. frenata (the type lo- cality of which is in Mexico). Hall’s concept of frenata (the basis for Wozencraft’s [1993] synonymy) implies genetic continuity among populations of long-tailed weasels from Can- ada to Bolivia, a hypothesis that has yet to be tested by any geographically extensive analysis of morphometric or molecular data.
REMARKS: Although uncommon and rarely seen, weasels are locally regarded as pests that enter houses to kill domesticated guinea pigs (Cavia porcellus). Hall (1951: 402) in- correctly copied the locality of NHRS A58/ 6157 as “‘Nara [sic] Papallacta’’ from the Swedish museum label rather than from Séd- erstr6m’s original (English) specimen tag.
> Kipp’s (1965) paper, cited as a generic revision by Wozencraft (1993), only analyzed character data from Patagonian material.
20 AMERICAN MUSEUM NOVITATES
Tremarctos ornatus (EF Cuvier)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: Apparently none.
REMARKS: The local population of specta- cled bears was studied by Suarez (1988), who described their seasonal distribution and diet on the eastern slopes of Cerro Antisana. No locally collected specimens, however, are apparently preserved in museums. Although I did not see any bears in the course of my fieldwork, signs of their foraging (consisting of shredded terrestrial bromeliads whose pith is an important item of diet) were sometimes observed above treeline.
Hippocamelus antisiensis (D’ Orbigny)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: An adult female speci- men and a juvenile male, formerly preserved in the Museo Nacional de Ciencias Naturales (Madrid), were collected on Cerro Antisana in 1865 by M. Jiménez de la Espada. This material was originally reported by Cabrera (1917), whose taxonomic identification can be accepted as authoritative. Unfortunately, both specimens were lost during the Spanish Civil War or its aftermath, when the collec- tions of the MNCN remained uncurated for several decades (J. Barreiro, personal com- mun).
REMARKS: The huemal is thought to be ex- tinct in Ecuador (Albuja, 1991), and only four specimens appear to have ever been col- lected there. Mysteriously, all are now lost. In addition to the Madrid specimens, a single skull (MACN 31.69) alleged to have come from eastern Ecuador was formerly pre- served in Buenos Aires (Tirira, 1999), and another specimen (from ‘‘Ecuador”’ without other locality data) was formerly in the FMNH (Elliot, 1907).
Odocoileus peruvianus (Gray)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: The holotype of Odo- coileus peruvianus consul Lonnberg is an adult female specimen (NHRS A63/0094), collected by L. Sdéderstr6ém in 1920 at “‘Gua- mani on the road to Papallacta, altitude 12,000 feet” (L6nnberg, 1922: 13; O. Gron- wall, personal commun.). Additional speci-
NO. 3421
mens of white-tailed deer (AMNH 66743, 66744) were collected by H.E. Anthony be- tween 4100 and 4300 m on Cerro Antisana im 1923.
TAXONOMY: Cabrera (1961) and most sub- sequent authors (including Grubb, 1993) treated Odocoileus peruvianus as a synonym or subspecies of O. virginianus, but all South American white-tailed deer appear to be di- agnostically distinct from the latter species (Molina and Molinari, 1999). Pending a comprehensive revision of the Neotropical forms of Odocoileus, | recognize peruvianus (with type locality in the Peruvian highlands) as a distinct species following Molina and Molinari’s (1999) provisional taxonomy.
REMARKS: White-tailed deer are said to be common throughout the paramo landscapes surrounding Cerro Antisana (Black, 1982), but I did not observe any in the course of my fieldwork.
Pudu mephistopheles (de Winton)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: The holotype of the northern pudu (BMNH 96.1.28.5), which I have not examined, was collected in the *‘Pa- ramo of Papallacta’’ by native collectors in the employ of Ludovic Séderstrém, the Swedish consul in Quito (de Winton, 1896). Another Séderstr6m specimen (which I did examine) is NHRS A58/4636, a dried skin with the skull inside labeled ‘‘Papallacta 12000 ft’’, collected in 1908 and originally reported by Lénnberg (1913).
TAXONOMY: The genus Pudu was revised by Hershkovitz (1982), who reviewed the scant literature on these rare deer and sum- marized information about the diagnostic characters, geographic distribution, and nat- ural history of P. mephistopheles.
REMARKS: Pudus are avidly hunted every- where they occur and appear to be uncom- mon or hard to observe throughout their dwindling geographic range. I did not see any in the course of my fieldwork near Pa- pallacata, but Black (1982) reported recent sightings of spoor in the paramos surround- ing Cerro Antisana.
Tapirus (Pinchacus) pinchaque (Roulin)
SPECIMENS COLLECTED: None. OTHER MATERIAL: Two specimens of the
2003
woolly tapir are known from Papallacta. The first (AMNH 70521), consisting of a skull collected by the Olallas (a family of profes- sional collectors) in 1925, is unaccompanied by other geographic data. The second (AMNH 149370) is the skin and skull of an individual that was captured alive by C. Cor- dier, who sold it to the New York Zoological Society in 1952; an index card in the AMNH collection archives indicates that this speci- men was captured at 11,500 ft (3505 m), but Hershkovitz (1954: 476) reported the capture elevation as 3150 m.
TAXONOMY: The taxonomy of living Neo- tropical tapirs was revised by Hershkovitz (1954), who diagnosed the subgenus Pincha- cus and established that Roulin’s is the oldest valid name for the woolly montane species.
REMARKS: Woolly tapirs have long been hunted in the vicinity of Papallacta and An- tisana, from which hides and meat are still exported for sale in the street markets of Qui- to (Downer, 1997). Although tracks and droppings are commonly encountered (Black, 1982), the animal itself is seldom seen.
Akodon latebricola (Anthony)
SPECIMENS COLLECTED: 10.6 km (by road) W Papallacta, 12,600 ft (UMMZ 155616); 7.5 km (by road) W Papallacta, 12,000 ft (UMMZ 155607-155615, 155768—155772, 155774); 6.2 km (by road) W Papallacta, ELF00TCUMMZ 155773; 1957753 155776): Rio Papallacta valley [3-5 km by trail NNW Papallacta], 11,100 ft (UMMZ 155617, 155618).
OTHER MATERIAL: None.
TAXONOMY: Originally described as Mi- croxus latebricola, this species has long been known only from the holotype (AMNH 67506) collected by G.H.H. Tate in 1924 at Hacienda San Francisco, a locality in the Cordillera Oriental east of Ambato (Anthony, 1924b: 3). A peculiar feature of AMNH 67506 is its intensely black fur, which is quite unlike the normal coloration of any other muroid rodent species known to me. Anthony (1924b) considered and rejected the hypothesis that the holotype was a melanistic mutant, but the rediscovery of this taxon at
VOSS: NEW THOMASOMYS 21
Papallacta lends support to the opposite con- clusion.
Except in pelage color, the Papallacta Specimens are qualitatively indistinguishable from the type of latebricola, and measure- ments of the type fall within the range of morphometric variation in the Papallacta se- ries. By contrast with the unnatural appear- ance of AMNH 67506, the Papallacta skins are dark grizzled-brown dorsally, and the ventral fur is gray-based with a superficial brownish wash; the ears, feet, and the dorsal surface of the tail are likewise dark brown, but the ventral surface of the tail is covered with long silvery hairs. Because brownish pigmentation is almost universal among the small akodontine rodents that inhabit humid Andean habitats, it is more parsimonious to assume that this is the normal coloration of Akodon latebricola, and that the coloration of the type is not, in point of fact, typical.
This species closely resembles Akodon bo- gotensis Thomas (1895a), another eastern- Andean species that was formerly referred to the genus Microxus. Among other shared similarities, both species differ from typical Akodon by their very small size; possession of a slender, tapering rostrum flanked by very shallow zygomatic notches (versus a shorter, stouter rostrum flanked by deeper zygomatic notches); origin of the superficial masseter from an indistinct tubercle or scar on the an- terior margin of the zygomatic plate (versus from a scar posteroventral to the anterior edge of the zygomatic plate); confluence of the buccinator- masticatory foramen and fo- ramen ovale (versus buccinator masticatory foramen and foramen ovale accessorius sep- arated by a vertical strut of the alisphenoid); proportionately shorter incisive foramina, wider parapterygoid fossae, and more inflat- ed bullae; and highly distinctive molars with opposite (versus alternating) cusps. Although phylogenetic analyses of mitochondrial DNA sequences do not support the separate gener- ic status of Microxus (as represented by the type species mimus Thomas; see Smith and Patton [1993] and references cited therein), sequence data from latebricola and bogoten- sis have not been analyzed. Despite their cur- rent generic classification, these two north- ern-Andean endemics clearly form a distinct clade that merits nomenclatural recognition.
22 AMERICAN MUSEUM NOVITATES
Subtle but consistent craniodental differences (M. G6mez-Laverde, personal commun.) dis- tinguish latebricola from bogotensis and support their current status as valid species.
REMARKS: In a previous list of Papallacta mammals (Voss, 1988: table 43), I misiden- tified this material as Microxus bogotensis.
FIELD OBSERVATIONS: The 21 specimens of Akodon latebricola that I collected near Pa- pallacta in 1980 were trapped at elevations ranging from 3380 to 3840 m. Of these, 16 were taken in the shrubby paéramo/forest eco- tone, 2 in Subalpine Rain Forest, 2 in grassy glades surrounded by Subalpine Rain Forest, and | in grassy paramo. All recorded cap- tures were on the ground: 9 in runways under dense bunch grass, 8 among mixed grasses and mossy shrubs, and 4 under moss mats or low herbs. Unlike other murid rodents that I collected near Papallacta (which appear to be strictly nocturnal), several individuals of A. latebricola were captured in broad daylight, between the time when traps were checked just after dawn and when they were rebaited in the late afternoon.
Akodon mollis Thomas
SPECIMENS COLLECTED: 12.5 km W (by road) Papallacta, 13,520 ft (UMMZ 155597); 10.6 km W (by road) Papallacta, 12,600 ft (UMMZ 155596, 155777); 7.5 km W (by road) Papallacta, 12,000 ft (UMMZ 155591-— 155595); 6.2 km W (by road) Papallacta, 11,700 ft (UMMZ 155586—155590, 155778— 155780).
OTHER MATERIAL: Three additional speci- mens were collected at ““Tablon, road to Pa- pallacta’? with recorded elevations of 10,500—11,500 ft [3200-3505 m] by L. Séd- erstrom in 1903 and 1913. Another nine specimens (AMNH 47156-47164) taken by the same collector in 1914 are labeled ‘Mt. Antisana 12000 feet”? [3658 m]. Forty-two more specimens (AMNH 66450-66491) were collected by H.E. Anthony and G.H.H. Tate between 4115 and 4570 m on Antisana in 1923. Lastly, three specimens (AMNH 67330, 67332, 67334) collected in 1924 by R. Olalla are labeled “‘Mt. Guamani, road to Papallacta’”’ with recorded elevations of 12,000—13,000 ft [3658-3962 m].
TAXONOMY: The Papallacta material close-
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ly resembles the type of Akodon mollis al- torum as originally described by Thomas (1913) based on a specimen collected at 2600 m in the Ecuadorean province of Cafiar. No substantive analysis of character data, how- ever, is available to support the current hy- pothesis (Cabrera, 1961; Musser and Carle- ton, 1993) that altorum, a highland taxon, is really conspecific with the geographically ad- jacent lowland forms mollis Thomas (1894) and fulvescens Hershkovitz (1940). As noted by Myers and Patton (1989), Akodon mollis as currently recognized has a very large geo- graphic range and exhibits substantial geo- graphic variation. Given their conclusion that fumeus Thomas (1902)—another taxon for- merly ranked as a subspecies or synonym of mollis—is a valid species, a comprehensive revision of this complex is long overdue.
FIELD OBSERVATIONS: The 16 specimens of Akodon mollis that I collected near Papallac- ta in 1980 were trapped at elevations ranging from 3600 to 4160 m. Of these, 13 were tak- en in the shrubby paéramo/forest ecotone, and 3 in grassy paramo. All recorded captures were on the ground: 5 in tunnels among the bases of tall bunch grass, 5 among wet litter under mossy shrubs, 4 in runways through mixed bunch grass and bushes, | in a rabbit trail beneath low herbaceous cover, and 1 be- neath an earth bank.
Anotomys leander Thomas
SPECIMENS COLLECTED: 8.9 km (by road) W Papallacta, 12,480 ft (AMNH 244607; UMMZ 126294); 8.2 km (by road) W Pa- pallacta, 12,000 ft (UMMZ 155603); 6.2 km (by road) W Papallacta, 11,700 ft (AMNH 244605, 244606; UMMZ 126295, 126296, 155598—155602).
OTHER MATERIAL: None.
TAXONOMY: The murid rodent tribe Ichth- yomyini was revised by Voss (1988), who summarized available information about the diagnostic morphological characters of Ano- tomys leander based in part on this material.
FIELD OBSERVATIONS: The 12 specimens of Anotomys leander that I collected near Pa- pallacta in 1978 and 1980 were trapped at elevations ranging from 3600 to 3750 m. All were taken along swift, cold, turbulent streams bordered by Subalpine Rain Forest
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or grassy paramo. Eight recorded captures were in traps set on rocky ledges or gravel beneath undercut banks at the water’s edge, but four specimens were trapped on rocks or logjams surrounded by swift current. More detailed habitat information about this series was summarized by Voss (1988: 412—413).
Chilomys instans (Thomas)
SPECIMENS COLLECTED: 7.5 km (by road) W Papallacta, 12,000 ft (UMMZ 155795); 6.2 km (by road) W Papallacta, 11,700 ft (UMMZ 155619, 155620).
OTHER MATERIAL: None.
TAXONOMY: The morphologically distinc- tive genus Chilomys Thomas (1897a) is cur- rently thought to contain only a single valid species, C. instans (Thomas, 1895b); another nominal taxon, fumeus Osgood (1912) is e1- ther a subspecies or synonym according to Cabrera (1961) and Musser and Carleton (1993). The Papallacta specimens closely re- semble the holotype of instans (BMNH 95.10.14.1, from Bogota) in qualitative char- acters, but they have slightly broader inter- orbits and shorter molar rows. A revision of this long-neglected northern-Andean endem- ic genus is necessary in order to evaluate the taxonomic significance of character variation among these and other specimens from Ec- uador, Colombia, and western Venezuela.
FIELD OBSERVATIONS: The three specimens of Chilomys instans that I collected near Pa- pallacta in 1980 were trapped at elevations ranging from 3600 to 3690 m. One specimen was trapped on a mossy log over a stream in Subalpine Rain Forest, another on the ground in a narrow runway beneath mossy shrubs in the same habitat, and the third in a mossy tunnel beneath bunch grass in the paéramo/ forest ecotone.
Microryzomys altissimus (Osgood)
SPECIMENS COLLECTED: 10.6 km (by road) W Papallacta, 12,600 ft (UMMZ 155799); 8.9 km (by road) W Papallacta, 12,480 ft (AMNH 248497); 8.2 km (by road) W Pa- pallacta, 12,200 ft (OUMMZ 155677); 7.5 km (by road) W Papallacta, 12,000 ft (UMMZ 155672—155676, 155802); 6.9 km (by road) W Papallacta, 12,020 ft (AMNH 248279, 248280); 6.2 km (by road) W Papallacta,
VOSS: NEW THOMASOMYS 23
11,700 ft (UMMZ 155798); near Papallacta, 10,480 ft (UMMZ 127125); 1.6 km (by road) E Papallacta, 10,250 ft (AMNH 248277).
OTHER MATERIAL: Three specimens col- lected by L. Séderstr6m in 1913 and 1914 are labeled “‘Papallacta 11,000 ft’? (AMNH 47068, 47071) or *““Tambo above Papallacta 12,000 ft” (AMNH 47069). Four others (AMNH _ 66577-66580) were collected by G.H.H. Tate in 1923 on Cerro Antisana at 13,500—13,600 ft [4116-4146 m].
TAXONOMY: The genus Microryzomys was revised by Carleton and Musser (1989), who provided morphological diagnoses of both currently recognized species based in part on the material listed above and below.
FIELD OBSERVATIONS: The 14 specimens of Microryzomys altissimus that I collected near Papallacta in 1978 and 1980 were trapped at elevations ranging from 3124 to 3840 m. Of these, five were taken in the shrubby péramo/ forest ecotone, four in grassy paramo, and three in Subalpine Rain Forest; two captures in anthropogenic habitats (secondary vege- tation surrounded by cow pastures) were the only ones below 3600 m. All recorded cap- tures were in traps set on the ground, five of which were placed along the margins of small streams; of the remaining nine captures (away from streams), six were in runways under tall bunch grass and/or low shrubs mixed with grass, two were in relatively open sites without grass inside the forest, and one was under a mossy bank.
Microryzomys minutus (Tomes)
SPECIMENS COLLECTED: 6.2 km (by road) W Papallacta (UMMZ 155678); Rio Papal- lacta valley [3-5 km by trail NNW Papallac- ta], 11,100 ft (UMMZ 155679, 155801); 1.4 km (by road) E Papallacta (UMMZ 155797); 1.6 km (by road) E Papallacta, 10,250 ft (AMNH 248278; UMMZ 127126).
OTHER MATERIAL: A single specimen (AMNH 46804) collected by L. Séderstr6m in 1914 is labeled “‘Papallacta 11,000 ft’’.
TAXONOMY: Carleton and Musser (1989) reviewed the morphological characters and taxonomy of this species, based in part on the material listed above.
FIELD OBSERVATIONS: The six specimens of Microryzomys minutus that I collected near
24 AMERICAN MUSEUM NOVITATES
Papallacta in 1978 and 1980 were trapped at elevations ranging from 3040 to 3570 m. Of these, three were taken in dense secondary growth surrounded by pastures (below 3200 m), and three were in Subalpine Rain Forest (above 3300 m). Five specimens were trapped on the ground (two on the banks of small streams, two under tangles of mossy debris, one inside a hollow trunk), but one was trapped on the mossy limb of a small tree.
Neusticomys monticolus Anthony
SPECIMENS COLLECTED: 8.2 km W Papal- lacta, 12,200 ft (UMMZ 155605, 155606); 6.2 km W Papallacta, 11,700 ft (UMMZ 155604); 1.6 km E Papallacta, 10,250 ft (UMMZ 126297; AMNH 244608, 244609).
OTHER MATERIAL: None.
TAXONOMY: The murid rodent tribe Ichth- yomyini was revised by Voss (1988), who provided a morphological diagnosis of the genus Neusticomys and its constituent spe- cies based in part on this material.
FIELD OBSERVATIONS: The six specimens of Neusticomys monticolus that I collected near Papallacta in 1978 and 1980 were trapped on the ground at elevations ranging from 3042 to 3719 m. Of these, three were taken along small rivulets descending narrow ravines choked with secondary vegetation, and three others were taken along the wet margins of larger streams bordered by Subalpine Rain Forest or grassy paramo vegetation.
Phyllotis haggardi Thomas
SPECIMENS COLLECTED: None.
OTHER MATERIAL: Nine specimens in the American Museum of Natural History (AMNH 66624-66632) were collected by H.E. Anthony and G.H.H. Tate between 4115 and 4570 m on Cerro Antisana in 1923. Oth- er specimens from the vicinity of Papallacta are labeled ‘“‘Papallacta 11,500 ft about’ (AMNH 46824, collected by L. Séderstrém in 1903) and ‘“‘Antisana 12,000 ft’? (AMNH 36293-36296, collected by W.B. Richardson ina .O13):
TAXONOMY: The genus Phyllotis was re- vised by Pearson (1958) and by Hershkovitz (1962), both of whom examined the material listed above. However, whereas Pearson re-
NO. 3421
ferred the local population to the subspecies P. haggardi fuscus Anthony (1924a), Hersh- kovitz attributed phenotypic variation among samples of P. haggardi to clinal environ- mental factors and did not recognize subspe- cific taxa.
Reithrodontomys (Aporodon) mexicanus (Saussure)
SPECIMENS COLLECTED: 8.9 km (by road) W Papallacta, 12,480 ft (UMMZ 127159).
OTHER MATERIAL: None.
TAXONOMY: The single available specimen of a harvest mouse from the Papallacta re- gion, a fluid-preserved old adult with extract- ed skull, is referable to Reithrodontomys mexicanus as that taxon was recognized in Hooper’s (1952) generic revision. According to Hooper, three valid subspecies of R. mex- icanus are present in northern Ecuador, in- cluding soderstromi Thomas (1898), milleri Allen (1912), and eremicus Hershkovitz (1941). Unfortunately, none can be effective- ly diagnosed by cranial characters, and meaningful pelage color comparisons are im- possible with the alcohol-bleached material at hand.
FIELD OBSERVATIONS: The specimen I col- lected in 1978 was trapped at an elevation of 3754 m next to a rocky stream bordered by grassy paramo vegetation.
Thomasomys aureus (Tomes) Figures 11-13
SPECIMENS COLLECTED: 6.2 km (by road) W Papallacta, 11,700 ft (AMNH 248281, 248498; UMMZ 127114, 155621—155624, 155626, 155707); Rio Papallacta valley [3— 5 km by trail NNW Papallacta], 11,100 ft (UMMZ 155625).
OTHER MATERIAL: None.
TAXONOMY: The holotype of Thomasomys aureus (BMNH 7.1.1.104) consists of the skin only of a specimen collected by Louis Fraser, allegedly at Pallatanga (1°59’S, 78°57'W; 1500 m above sea level) in the Ecuadorean province of Chimborazo (Allen, 1914; Ellerman, 1941; Cabrera, 1961), or at Gualaquiza (3°24’'S, 78°33'W; 971 m above sea level) in the Ecuadorean province of Mo- rona-Santiago (Thomas, 1920). Neither lo- cality, however, is within the usual altitudinal
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rig, ls
VOSS: NEW THOMASOMYS 25
Dorsal cranial views of eight Thomasomys species that occur in the Cordillera Oriental of
northern Ecuador. Top row (left to right): 7. aureus (UMMZ 127114), 7. baeops (UMMZ 155708), T. cinnameus (UMMZ 155671), T. erro (UMMZ 155713). Bottom row (eft to right): T. paramorum (UMMZ 155737), T. rhoadsi (AMNH 66256), T. silvestris (USNM 513592), T. ucucha (UMMZ
155644).
range of this species (ca. 3000—4000 m), and the exact provenance of Fraser’s Ecuadorean material is uncertain due to inadequate la- belling and the lack of detailed field records (Gardner, 1983). Despite the absence of cra- nial material and a definite geographic da-
tum, however, the type serves to establish that aureus is a distinctively large, shaggy rat with grizzled yellowish-brown dorsal fur; yellow-washed, gray-based ventral fur; long, blackish mystacial vibrissae; dark, broad hind feet with semiopposable fifth digits; and
26 AMERICAN MUSEUM NOVITATES
NO. 3421
Fig. 12. Ventral cranial views of eight Thomasomys species from the Cordillera Oriental of northern Ecuador. Top row (left to right): 7. aureus (UMMZ 127114), 7. baeops (UMMZ 155708), T. cinnameus (UMMZ 155671), 7. erro (UMMZ 155713). Bottom row (left to right): T. paramorum (UMMZ 155737), T. rhoadsi (AMNH 66256), 7. silvestris (USNM 513592), T. ucucha (UMMZ 155644).
a tail that is much longer than the combined length of head-and-body. Other Ecuadorean specimens with these external characters ex- hibit the qualitative craniodental characters listed in table 2 and approximate the range of morphometric variation summarized in ta- ble:3:
Among the several nominal taxa currently synonymized with Thomasomys aureus by Musser and Carleton (1993), the same qual- itative and morphometric traits are shared by princeps Thomas (1895a) from the eastern Andes of Colombia and by altorum Allen (1914) from the western Andes of Ecuador.
2003 VOSS: NEW THOMASOMYS 2d
Fig. 13. Lateral cranial and mandibular views of eight Thomasomys species from the Cordillera Oriental of northern Ecuador. Left side (top to bottom): T. aureus (UMMZ 127114), T. baeops (UMMZ 155708), 7. cinnameus (UMMZ 155671), T. erro (UMMZ 155713). Right column (top to bottom): T. paramorum (UMMZ 155737), T. rhoadsi (AMNH 66256), T. silvestris (USNM 513592), 7. ucucha (UMMZ 155644).
28 AMERICAN MUSEUM NOVITATES
TABLE 3 Measurements (mm) and Weights (g) of Thomasomys aureus
Papallacta series#
Sex 3 females, 4 males HBL 168 (143-178) 6 LT 218 (186-234) 6 HF 38 (38-40) 6 Ear 23 (20-25) 6 CIL 35.9 (32.4—38.3) 6 LD 10.4 (9.0-11.2) 6 LM 7.4 (7.2-7.7) 6 BM1 2.2 (2.1-2.3) 6 LIF 8.4 (7.3-9.1) 6 BIF 3.1 (2.8-3.4) 6 BPB 3.3 (3.0-3.8) 6 BZP 3.4 (2.9-3.6) 6 LIB 5.1 (4.9-5.5) 6 ZB 20.8 (18.6-—22.2) 6 DI 2.0 (1.6—2.2) 6 BIT 2.8 (2.3-3.1) 6 Weight” >100 (75—-100+) 6
4 Tabulated statistics include the mean, the observed range (in parentheses), and the sample size for each measurement of the following series: UMMZ 127114, 155621-155626.
b Specimens were weighed with scales having a maximum capacity of 100 g.
Other putatively synonymous taxa, however, differ conspicuously from aureus in side-by- side morphological comparisons: popayanus Allen (1912) from the western Andes of Co- lombia and nicefori Thomas (1921) from the Colombian central Andes have substantially shorter (33-34 mm) hind feet and smaller (6.0—6.6 mm) molar toothrows, whereas praetor Thomas (1900) from northern Peru has grayish dorsal fur, pale-silvery ventral fur, pale hind feet, shorter tail, narrower in- terorbit, and a broad, distinctively flattened braincase. These three taxa were first treated as conspecific with 7. aureus by Cabrera (1961), who (as usual) offered no explana- tion for his nomenclatural changes. In view of such trenchant character differences, at least four species appear to be represented in this complex: 7. aureus Gncluding altorum and princeps), T. praetor, and T. popayanus (possibly including nicefori).
FIELD OBSERVATIONS: The 10 specimens of Thomasomys aureus that I collected near Pa- pallacta in 1978 and 1980 were all taken in
NO. 3421
Subalpine Rain Forest at elevations ranging from 3380 to 3570 m. Six were trapped in well-worn paths through mats of moss and liverworts on horizontal tree limbs, and four were trapped on the ground. Of the latter, two were trapped at the edge of a stream, one was trapped among tall grass in a clearing, and one was trapped in a runway through dense mats of moss.
Thomasomys baeops (Thomas) Figures 11-13
SPECIMENS COLLECTED: 6.2 km (by road) W Papallacta, 11,700 ft (AMNH 248499; UMMZ 127117, 155630-—155632, 155708, 155739); Rio Papallacta valley (3-5 km by trail NNW Papallacta), 11,100 ft (UMMZ 155629); 1.4 km (by road) E Papallacta, 9,980 ft (UMMZ 127118, 155627, 155628, 1597.02).
OTHER MATERIAL: Another specimen (KU 109495) was collected by W.E. Duellman in 1967 near Laguna Papallacta at 3350 m el- evation.
TAXONOMY: The type material of Thoma- somys baeops consists of a single specimen (BMNH 98.8.1.7) collected near the Rio Pita in the Ecuadorean province of Pichincha, from which a small series of topotypes is also available for comparisons. The Papal- lacta series is essentially indistinguishable from this material in qualitative characters of the skin and skull, as well as in measure- ments (table 4). No synonyms of 7. baeops are currently recognized.
FIELD OBSERVATIONS: The 12 specimens of Thomasomys baeops that I collected near Pa- pallacta in 1978 and 1980 were trapped at elevations ranging from 3040 to 3565 m. Of these, one was taken in the shrubby paramo/ forest ecotone, seven were in Subalpine Rain Forest, and four were in dense thickets of secondary growth at the bottom of a narrow ravine surrounded by pastures. Eight speci- mens were trapped on the ground: three along the wet margins of small streams, three in narrow trails through mossy debris and damp leaf litter, one under a mossy log, and one in a hole in a bank under the roots of a tree. Four specimens were trapped on the mossy branches of small trees.
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TABLE 4 Measurements (mm) and Weights (g) of Thomasomys baeops
Papallacta series? Topotypes>
Sex 3 females, 8 males 5 females, 4 males HBL 107 + 6 (98-117) 11 105 (95-120) 9 LT 135 + 8 (119-147) 11 125 (106-140) 9 HF 25 + 1 (24-27) 11 25 (24—26) 9 Ear 18 + 1 (16-19) 11 —
CIL 25.7 + 0.8 (24.1-27.0) 11 25.8 (24.4—27.7) 9 LD 7.4 + 0.3 (6.9-7.9) 11 7.2 (6.5—8.0) 9 LM 4.4 + 0.1 (4.2-4.5) 11 4.6 (4.4-4.8) 9 BM1 1.3 + 0.0 (1.3-1.4) 11 1.3 (1.2-1.4) 9 LIF 5.7 + 0.2 (5.2-6.1) 11 5.3 (4.8-5.6) 9 BIF 2.1 + 0.1 (1.9-2.3) 11 1.8 (1.6-2.0) 9 BPB 3.2 + 0.2 (2.9-3.5) 11 3.1 (2.8-3.4) 9 BZP 2.3 + 0.1 (2.1-2.5) 11 2.4 (2.2-2.7) 9 LIB 4.5 + 0.1 (4.24.7) 11 4.3 (4.2-4.5) 9 ZB 15.3 + 0.5 (14.5-15.9) 10 15.1 (14.1-15.8) 9 DI 1.6 + 0.1 (1.4-1.7) 11 1.6 (1.5~1.7) 9 BIT 1.8 + 0.1 (1.6-1.9) 11 1.7 (1.61.9) 9 Weight 36 + 5 (27-45) 10 —
4 Tabulated statistics include the mean plus or minus one standard deviation, the observed range (in parentheses), and the sample size for each measurement of the following series: AMNH 248499; UMMZ 127117, 127118, 155627-155629, 155631, 155632, 155708, 155739, 155767.
b From the Rio Pita, Provincia Pichincha, Ecuador (includ- ing sublocalities “Cafion of Rio Pita”, “Upper Rio Pita”, and “Santa Rosa above Rio Pita”). The mean, the observed range (in parentheses), and the sample size are provided for each measurement of the following series: AMNH 65006, 65007, 65009-65011, 64994, 64996-64998).
Thomasomys cinnameus Anthony Figures 11-13
SPECIMENS COLLECTED: 1.6 km (by road) W Papallacta, 10,500 ft (UMMZ 155668— 155670); Rio Papallacta valley [3-5 km by trail NNW Papallacta], 11,100 ft (AMNH 155671, 155800).
OTHER MATERIAL: None.
TAXONOMY: This material of Thomasomys cinnameus was the first to be reported (by Voss, 1988: table 43) since the original de- scription based on a single specimen collect- ed at 8000 ft (2438 m) near Hacienda San Francisco, Provincia Tunguragua, Ecuador (Anthony, 1924b). Side-by-side comparisons indicate that the Papallacta series closely re- sembles the holotype (AMNH 67401) in all qualitative and most quantitative characters.
VOSS: NEW THOMASOMYS 29
Although the holotype slightly exceeds the Papallacta specimens in several external and craniodental measurements (table 5), the dif- ferences are so small and the number of Pa- pallacta specimens (five) is so few that these discrepancies do not seem taxonomically sig- nificant.
One of the smallest known species of the genus, Thomasomys cinnameus 1s currently regarded as a subspecies or junior synonym of 7. gracilis Thomas (1917), originally de- scribed from a specimen collected at Machu Picchu in southern Peru (Cabrera, 1961; Musser and Carleton, 1993). However, the hypothesis that cinnameus and gracilis (with type localities separated by 1500 km of high- ly dissected mountainous terrain) are conspe- cific is unsupported by any published anal- ysis or discussion of character data. Rather, my examination of both holotypes and other representative material® indicates that these are unambiguously diagnosable taxa that should be recognized as distinct species.
Although similar to Thomasomys gracilis in size, external proportions, and pelage col- oration, T. cinnameus consistently lacks ge- nal vibrissae, long black tactile hairs of the upper cheek that are consistently present in gracilis. Among other trenchant craniodental comparisons, cinnameus is distinguished by (1) incisive foramina that are widest poste- riorly, behind the maxillary/premaxillary su- ture; (2) absence of sphenopalatine vacuities; (3) smaller and less inflated auditory bullae; and (4) larger and more hypsodont molars with weakly developed cingula and stylar cusps. By contrast, gracilis exhibits (1) in- cisive foramina that are widest anteriorly, at or near the maxillary/premaxillary suture; (2) large sphenopalatine vacuities that perforate the bony roof of the mesopterygoid fossa on each side of the basisphenoid/presphenoid suture; (3) larger and more inflated auditory bullae; and (4) smaller, brachydont molars with better developed cingula and _ stylar cusps.
©The comparative material of Thomasomys gracilis that I examined included the holotype (USNM 194816), two topotypes (USNM 194799, 194801), and 12 other specimens (AMNH 95206, 95207; USNM_ 194785— 194787, 194790, 194807, 194808, 194811-—194813), all of which were collected between 2774 and 4267 m above sea level in the Peruvian department of Cusco.
30 AMERICAN MUSEUM NOVITATES
TABLE 5 Measurements (mm) and Weights (g) of Thomasomys cinnameus
Papallacta series# Holotype
Sex 3 females, two males female HBL 84 (82-87) 5 90
LT 118 (110-128) 5 120
HF 22 (21-23) 5 24
Ear 15 (14-16) 5 -
CIL 22.4 (22.0-23.0) 4 23.4 LD 6.8 (6.5-7.1) 5 7.0 LM 3.9 (3.84.0) 5 4.1 BMI 1.2 (1.2-1.3) 5 1.3 LIF 5.0 (4.8-5.3) 5 5.5 BIF 1.9 (1.8-2.0) 4 1.9 BPB 3.1 (2.9-3.3) 4 3.3 BZP 1.7 (1.6-2.0) 5 1.6 LIB 4.2 (4.14.4) 4 4.1 ZB 13.4 (12.9-13.6) 4 13.5 DI 1.2 (1.1-1.2) 5 1.2 BIT 1.6 (1.5-1.7) 5 1.6 Weight 17 (14-19) 5 -
4 Tabulated statistics include the mean, the observed range (in parentheses), and the sample size for each measurement of the following series: UMMZ 155668-155671, 155800.
6’ AMNH 67401, from Hacienda San Francisco, Provincia Tugurahua, Ecuador.
Thomasomys hudsoni Anthony (1923) is another small Ecuadorean taxon that has been treated without explanation as a syno- nym or subspecies of 7. gracilis (see Ca- brera, 1961; Musser and Carleton, 1993). However, I agree with Anthony (1924b) that hudsoni is a distinct species, differing from both gracilis and cinnameus in details of col- oration and craniodental morphology. Unlike any specimens of the other small species, the type of hudsoni (AMNH 47690, from Bes- tidn in Provincia Azuay) has a rostrum that is peculiarly produced beyond the incisors as a flaring bony tube with a concave (rather than convex) dorsal profile. As in cinnameus (and unlike gracilis) genal vibrissae and sphenopalatine vacuities are absent in hud- soni, but as in gracilis (and unlike cinna- meus) the incisive foramina are widest ante- riorly (near the maxillary/premaxillary su- ture). The auditory bullae of hudsoni are larger and more inflated than those of cin- nameus but smaller and less inflated than those of gracilis. Unfortunately, the molars
NO. 3421
of the type (and only known specimen) of hudsoni are too worn to support confident dental comparisons.
FIELD OBSERVATIONS: The five specimens of Thomasomys cinnameus that I collected near Papallacta in 1980 were trapped at ele- vations ranging from 3200 to 3380 m. Of these, three were taken among mossy boul- ders in an old lava flow that impounds the Rio Tambo to form Laguna Papallacta (fig. 1), and two were trapped on the ground in Subalpine Rain Forest in the valley of the Rio Papallacta 3—5 km (by trail) NNW of the town.
Thomasomys erro Anthony Figures 11-13
SPECIMENS COLLECTED: 6.2 km (by road) W Papallacta, 11,700 ft (UMMZ 155711); Rio Papallacta valley [3-5 km by trail NNW Papallacta], 11,100 ft (UMMZ 155640-— 155642, 155712, 155713); 1.4 km (by road) E Papallacta (AMNH 248283; UMMZ 155633—155639, 155709, 155710); 9 km (by road) E Papallacta, 9280 ft (UMMZ 127133).
OTHER MATERIAL: None.
TAXONOMY: Thomasomys erro was oOrigi- nally described on the basis of a single spec- imen (AMNH 68195) collected by the Olal- las on the “upper slopes of Mt. Sumaco, exact altitude unknown, but probably 8000— 9000 feet [2440—2740 m], at head of the Rio Suno, a tributary of the Rio Napo, eastern Ecuador; June 10, 1924” (Anthony, 1926: 5). Although only about 50 km SE of Papallacta, Volcan Sumaco (0°34'S, 77°38'W) is an iso- lated peak that is separated from the main range of the Cordillera Oriental by the low- land valley of the Rio Quijos (fig. 14). Pop- ulations of montane organisms on the upper slopes of Sumaco are therefore likely to be ecologically disjunct from those in the vicin- ity of Papallacta.
The Papallacta specimens are the only ad- ditional material of Thomasomys erro to have been collected since 1924 and merit close comparison with the holotype (AMNH 68195). No noteworthy differences in pelage color or other external characters are appar- ent, however. The skull of AMNH 68195 is partially crushed, so only an incomplete set of measurements can be taken, but most of
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VOSS: NEW THOMASOMYS 31
e os i a a ea i= Pe iy te beings
Fig. 14. The type locality of Thomasomys erro, Volcan Sumaco (0°34'S, 77°38'’W) is an isolated peak that rises to 3840 m above sea level in Provincia Napo, eastern Ecuador. Photographed by the author, looking northeast from the crest of the Cordillera de los Guacamayos on the road between Baeza
and Tena, 3 August 1980.
these fall within the range of variation ob- served among the Papallacta specimens; the exceptions are two molar dimensions in which the type is slightly larger (table 6). In all qualitative craniodental comparisons, the holotype appears to be indistinguishable from the Papallacta series and appears to rep- resent the same taxon.
Cabrera (1961) listed Thomasomys erro as a subspecies of T. cinereiventer Allen (1912) without explanation, and no discussion of character information has been published to justify the current treatment of erro as a ju- nior synonym of that species (e.g., by Musser and Carleton, 1993). However, side-by-side comparisons of the holotypes and other rep- resentative material of erro and cinereiventer do not support the hypothesis that these taxa are conspecific. Among other differences, typical cinereiventer from the Cordillera Oc-
cidental of southern Colombia’ is a much bigger animal with longer hind feet (33-36 mm); deeper zygomatic notches; less inflated interorbital region; more strongly convergent zygomatic arches; more elongate (less glob- ular) braincase; broader and more vertically oriented zygomatic plates; consistently sep- arate buccinator-masticatory and accessory oval foramina; larger (5.7—6.2 mm), incipi- ently lophodont molars with interpenetrating lingual and labial flexi (see illustrations and discussion of this trait in Voss, 1993); and relatively much broader incisors. Other Col-
7Tn addition to the holotype of Thomasomys cinereiv- enter (AMNH 32436), I examined 17 paratypes (AMNH 32417, 32419, 32421-32425, 32427, 32428, 32430, 32433-32435, 32437-32440), all of which were col- lected at 3152 m on the Pacific slope of the Cordillera Occidental west of Popaydn in Departamento Cauca, Colombia.
Bon AMERICAN MUSEUM NOVITATES
TABLE 6 Measurements (mm) and Weights (g) of Thomasomys erro
Papallacta series# Holotype? Sex 6 females, 5 males male HBL 114 + 8 (104-130) 11 - LT 150 + 13 (131-175) 11 — HF 31 + 1 (28-32) 11 31 Ear 20 + 1 (19-21) 11 at CIL 26.5 + 1.3 (25.0-28.6) 11 - LD 7.7 = 0.5 (6.9-8.5) 11 8.3 LM 4.6 + 0.1 (4.54.8) 11 5.0 BMI 1.6 + 0.0 (1.5-1.6) 11 1.7 LIF 5.5 + 0.3 (5.1-6.0) 11 5.5 BIF 2.4 + 0.2 (2.2-2.9) 1] 2.4 BPB 3.2 + 0.3 (2.7-3.7) 11 3.2 BZP 1.4 + 0.1 (1.3-1.7) Il 1.6 LIB 5.7 + 0.2 (5.4-5.9) 11 5.8 ZB 14.8 + 0.6 (13.9-15.6) 11 - DI 1.4 + 0.1 (1.2+1.6) 11 1.4 BIT 1.4 + 0.1 (1.3-1.6) 11 1.4 Weight 38 + 7 (28-46) 11 I
4 Tabulated statistics include the mean plus or minus one standard deviation, the observed range (in parentheses), and the same size for each measurement of the following series: AMNH 248283; UMMZ 127133, 155634, 155636, 155637, 155639-155642, 155712, 155713.
b AMNH 68195, from Volcan Sumaco, Provincia Napo, Ecuador.
ombian taxa that are currently considered to be subspecies or synonyms of 7. cinereiv- enter—including contradictus Anthony (1925) from the Cordillera Central and dis- par Anthony (1925) from the Cordillera Ori- ental—are smaller than the nominotypical form but do not exhibit any other noteworthy similarities with 7. erro.
FIELD OBSERVATIONS: I collected 17 spec- imens of Thomasomys erro in the vicinity of Papallacta, at elevations ranging from 2830 to 3570 m. Of these, 11 were taken in dense secondary vegetation, 5 in Subalpine Rain Forest, and | in Upper Montane Rain Forest. All recorded captures were on the ground. Eleven specimens were trapped in runways through wet leaf litter and mossy debris; three were trapped beneath mossy logs, branches, or roots; and one was trapped in- side the trunk of a hollow tree.
NO. 3421
Thomasomys paramorum Thomas Figures 11-13
SPECIMENS COLLECTED: 10.6 km (by road) W Papallacta, 12,600 ft (UMMZ 155662-— 155667); 7.5 km (by road) W Papallacta, 12,000 ft (UMMZ 155661, 155745—155747); 6.2 km (by road) W Papallacta, 11,700 ft (AMNH 248282; UMMZ 127123, 127124, 155656—155660, 155737, 155738, 155740— 155744, 155748—155751).
OTHER MATERIAL: Five’ specimens (AMNH 46627, 46628, 46631, 46633, 46636) were collected at *“‘E] Tambo, Papal- lacta 12,000 ft’? by L. Sdderstr6m between 1912 and 1914, and another specimen (AMNH 46643) taken by the same collector at the same time is labeled ‘“Tablon, road to Papallacta 11,000 ft about’’. Five additional SdderstrO6m specimens (AMNH 46629, 46630, 46634, 46641, 46642) are labeled **Cuyuco [probably Cuyuja] below Papallac- ta, 7000 ft’’.
TAXONOMY: The type material of Thoma- somys paramorum consists of a single spec- imen collected at an Ecuadorean locality that Thomas (1898: 454) described vaguely as ‘“‘Paramo, south of Chimborazo’’, but a small series from Urbina (1°30’S, 78°44’W) just a few kilometers SE of Chimborazo can be considered topotypic. Although these topo- types average larger than the Papallacta sam- ple in most measurements and have propor- tionately narrower zygomatic plates (table 7), the two series are similar in qualitative ex- ternal and craniodental traits and appear to represent the same taxon. No synonyms of 7. Paramorum are cutrently recognized.
FIELD OBSERVATIONS: I recorded 29 cap- tures of Thomasomys paramorum near Pa- pallacta in 1978 and 1980 (one specimen was lost in the field), at elevations ranging from 3570 to 3840 m. Of these, 15 were taken in Subalpine Rain Forest, 7 in Polylepis thickets in the paramo, and 7 in the shrubby paramo/ forest ecotone. Twenty-two captures were on the ground, of which nine were trapped in runways through moss, six along the banks of small streams, six in wet leaf litter under shrubs and branches, and one under a clump of grass. Seven specimens were trapped in low, mossy trees.
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TABLE 7 Measurements (mm) and Weights (g) of Thomasomys paramorum
Papallacta series# Topotypes®
Sex 14 females, 10 males 6 females, 3 males HBL 92 + 5 (80-103) 24 99 (91-106) 9 LT 121 + § (113-133) 24 122 (114-129) 9 HF 24 + 1 (23-25) 24 25 (24-26) 9 Ear 18 + I (16-19) 24 -
CIL 23.3 + 0.6 (21.8-24.3) 24 24.3 (23.0—25.4) 9 LD 6.6 + 0.3 (6.0-7.1) 24 6.9 (6.2-7.5) 9 LM 4.0 + 0.1 (3.8-4.3) 24 4.4 (4.2-4.5) 9 BM1 1.2 + 0.0 (1.1-1.3) 24 1.4 (1.3-1.4) 9 LIF 5.3 + 0.2 (4.9-5.7) 24 5.7 (5.4-6.1) 9 BIF 1.9 + 0.1 (1.8-2.1) 24 2.0 (1.9-2.1) 9 BPB 3.0 + 0.2 (2.7-3.4) 24 3.1 (2.7-3.4) 9 BZP 2.1 + 0.1 (1.8-2.3) 24 2.0 (1.8~2.2) 9 LIB 4.3 + 0.1 (4.1+4.5) 24 4.4 (4.2-4.5) 9 ZB 13.5 + 0.3 (13.0-14.2) 24 14.3 (13.7-14.8) 8 DI 1.2 + 0.1 (1.1-1.3) 24 1.3 (1.2—1.4) 9 BIT 1.5 + 0.1 (1.3-1.6) 24 1.6 (1.4—1.8) 8
Weight 21 + 2 (17-26) 24 -
4 Tabulated statistics include the mean plus or minus one standard deviation, the observed range (in parentheses), and the sample size for each measurement of the following series: AMNH 248501; UMMZ 127123, 127124, 155656-155667, 155737, 155738, 155740-155744, 155746, 155749, 155750.
b’ From Urbina, Provincia Chimborazo, Ecuador (see text). Tabulated statistics include the mean, the observed range (in parentheses), and the sample size for each measurement of the following series: AMNH 64871, 64872, 64874, 64877-64880, 64882, 64883.
Thomasomys rhoadsi Stone Figures 11-13
SPECIMENS COLLECTED: None.
OTHER MATERIAL: Five specimens (FMNH 43246-43250) collected by R. Olalla in 1934 are labeled ‘“‘Cerro Antisana, Andes Orien- tales’’, and two others (BMNH 54.553, 55.554) collected by C.S. Webb in 1937 are labeled ““Mt. Antisana, E. Andes 12,500-— 13,000 ft’’.
TAXONOMY: Thomasomys rhoadsi was originally described from material collected in 1911 by S.N. Rhoads on Volcan (*‘Mt.’’) Pichincha in the western Andes above Quito (Stone, 1914: 12). The Antisana specimens listed above were compared with a series of topotypes, which they resemble qualitatively despite averaging slightly larger in several external and craniodental dimensions (table
VOSS: NEW THOMASOMYS 33
TABLE 8 Measurements (mm) of Thomasomys rhoadsi*
Antisana series® Topotypes¢ Sex 2 females, 1 male 6 females, 4 males HBL 131 (130-132) 3 123 (112-128) 10 LT 116 (114-118) 3 117 (110-123) HF 29 (29-30) 3 29 (28-31) 10 Ear 18 (18-19) 3 - CIL 30.0 (30.0-30.0) 1 29.0 (28.3—29.8) 7 LD 9.4 (9.3-9.4) 2 9.0 (8.5—9.4) 10 LM 5.4 (5.4-5.5) 3 5.4 (5.1-5.6) 10 BM1 1.6 (1.5-1.6) 3 1.6 (1.5—1.6) 10 LIF 7.0 (7.0-7.1) 2 6.6 (6.2—7.0) 10 BIF 2.9 (2.9-2.9) 2 2.7 (2.62.9) 10 BPB 4.0 (3.9-4.1) 3 3.6 (3.4—3.9) 10 BZP 2.2 (2.1—2.4) 2 2.3 (2.1—2.4) 10 LIB 5.5 (5.4-5.7) 3 5.6 (5.2-5.8) 10 ZB 16.4 (16.2-16.7) 2 15.8 (15.4—16.3) 8 DI 1.6 (1.4-1.6) 3 1.5 (1.3-1.5) 10 BIT 1.9 (1.8-2.0) 2 1.8 (1.5-2.0) 10
4 Tabulated statistics for each measurement of both series include the mean, the observed range (in parentheses), and the sample size. Measurements of the ear and weights were not recorded by the collectors of these series.
b’ FMNH 43247, 43249, 43250.
¢ From Volcan (“Mount”) Pichincha, Provincia Pichincha, Ecuador: AMNH 66252-66257, 66259-66262.
8). In the absence of other character differ- ences between these samples, I assume that they represent the same taxon. An apparently related form originally described as T. rhoad- si fumeus is substantially smaller than typical rhoadsi and also differs from it in qualitative external and cranial characters as remarked by Anthony (1924b).
REMARKS: Although Olalla’s and Webb’s labels do not state whether their specimens were collected on the eastern or western slopes of Antisana, it seems probable they were collected near Hacienda Antisana on the western side, the only inhabited site de- scribed in published accounts of visitors to this famous mountain (e.g., Orton, 1870; Whymper, 1892; Emerson and Johnson, 1960).
Thomasomys silvestris Anthony Figures 11-13
SPECIMENS COLLECTED: None. OTHER MATERIAL COLLECTED: A_ single
34 AMERICAN MUSEUM NOVITATES
TABLE 9 Measurements (mm) of Thomasomys silvestris*
Antisana specimen? Type series¢
Sex female 8 females, 4 males
HBL 117 106 + 9 (95-127) 10
LT 148 148 + 6 (139-157) 10 HF 27 29 + 1 (28-30) 10
Ear 18 -
CIL - 26.6 + 0.7 (25.4-27.3) 12 LD 8.7 8.0 + 0.3 (7.6-8.5) 12 LM - 4.9 + 0.1 (4.8-5.1) 11 BM1 _ 1.6 + 0.0 (1.6—1.7) 12 LIF 5.7 5.6 + 0.3 (5.1-6.1) 12 BIF 2.7 2.3 + 0.2 (1.9-2.6) 12 BPB - 3.3 + 0.3 (2.8-3.9) 12 BZP 2.1 2.0 + 0.1 (1.82.2) 12 LIB 5.4 5.1 + 0.1 (4.9-5.3) 12 ZB 16.6 15.6 + 0.5 (14.8-16.4) 10 DI 1.4 1.4 + 0.1 (1.3-1.6) 12 BIT 1.8 1.8 + 0.2 (1.5—2.0) 12
4 Weights were not recorded for specimens in either series.
b FMNH 43251, an old adult (TWC 5) with molars worn below the widest part of the crown, and therefore unmeasur- able (see text).
© On the road to Santo Domingo (‘Santo Domingo Trail’) northwest of Volcén Corazén (0°32'S, 78°39'W), Provincia Pichincha, Ecuador (including sublocalities “Las Maquinas” and “Forest N.W. of Corazon”). Tabulated statistics include the sample mean plus or minus one standard deviation, the observed range (in parentheses), and the sample size for each measurement of the following series: AMNH 66280, 66283-66289. 66293. 66296, 63364, 63365.
specimen (FMNH 43251) was collected on Cerro Antisana by R. Olalla in 1934.
TAXONOMY: Thomasomys_ silvestris was originally described from a large series of specimens collected on the densely forested western slope of the western Andes south of Quito in the Ecuadorean provinces of Pichin- cha and Bolivar (Anthony, 1924a). I com- pared the Antisana specimen with the type series, which it exactly resembles in quali- tative characters. The Antisana specimen is an old adult, however, with molars that are worn below the widest part of the crowns, so most of its measurements are larger than those of adults with measurable teeth in the type series (table 9). No synonyms of T. sil- vestris are currently recognized.
REMARKS: It seems probable that the An- tisana specimen of Thomasomys. silvestris was collected on the western side of Antisana
NO. 3421
as previously remarked for similarly labeled specimens of 7. rhoadsi collected at the same time by the same collector.
Coendou quichua Thomas
SPECIMENS COLLECTED: None.
OTHER MATERIAL: I examined three NHRS specimens (A58/2822, A58/2962, A59/2962) collected by Ludovic Séderstr6m in 1911 at ‘““Tablon above Tumbaco”’ with recorded el- evations of 9000—11,000 ft [2744-3354 m].
TAXONOMY: Coendou quichua is a mor- phologically distinctive porcupine whose di- agnostic characters were accurately described by Thomas (1899). Cabrera (1961), however, treated guichua as a subspecies of C. bicolor Tschudi without providing any justification for doing so. Although Emmons (1990), Al- buja (1991), Tirira (1999), and Alberico et al. (1999) have subsequently recognized that quichua is a valid species, some checklists (e.g., Woods, 1993) continue to treat this name as a synonym of bicolor.
To date, no rationale has been provided for the zoogeographically incoherent and mor- phologically divergent collection of taxa that Cabrera (1961) lumped together as Coendou bicolor. Although this name has been applied by authors to a wide range of morphologies, specimens collected in the vicinity of the Pe- ruvian type locality (e.g., AMNH 147500, FMNH 65799) are distinctively large por- cupines (ca. 900 mm total length) with tails that are almost as long as the combined length of head-and-body; the visible dorsal pelage consists entirely of bicolored (black- tipped) quills, of which those over the fore- quarters are conspicuously longer than those over the lower back and rump. By contrast, C. quichua is much smaller (ca. 600 mm or less) with a proportionately much shorter tail (approximately half the length of head-and- body) and tricolored (pale-tipped) dorsal quills that are not conspicuously longer over the forequarters than on the lower back and rump. Cranially, qguichua has a proportion- ately narrower rostrum than bicolor, smaller orbits, less expanded jugals, and less inflated frontal sinuses. Other relevant morphological comparisons will be provided in an upcom- ing generic revision (Voss, in prep.), but the characters given here together with other
2003
traits mentioned by Emmons (1990) and AI- berico et al. (1999) are sufficient for unam- biguous identifications of these dissimilar taxa.
REMARKS: The original specimen tag of NHRS A58/2822 notes that the animal was ‘‘found in the underbrush’’. Lonnberg (1913) originally reported this material as having been collected above Tumbaco, without men- tioning the actual collecting site (Tablon).
Cuniculus (Stictomys) taczanowskii (Stolzmann)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: A single specimen that I have not examined (QCAZ 954) was col- lected in the paramo near Paso de Guamani by G. Onore in 1993 (D. Tirira, personal commun.).
TAXONOMY: The mountain paca is mor- phologically distinctive (Thomas, 1924) and was formerly distinguished generically (as Stictomys) from the lowland paca (Cuniculus paca). Although only a single species of mountain paca is currently recognized, no critical analysis of morphological or molec- ular data is currently available to test the hy- pothesis that C. taczanowskii (from Ecuador and Peru) is actually conspecific with popu- lations from Venezuela and Colombia that were formerly known as C. sierrae (e.g., by Thomas, 1905; Krumbiegel, 1940). The In- ternational Commission on Zoological No- menclature (ICZN, 1998) recently ruled that Cuniculus Brisson, 1762, is the oldest avail- able name for pacas, previously referred by most American authors to Agouti Lacépéde, L799.
Sylvilagus brasiliensis (Linnaeus)
SPECIMENS COLLECTED: None.
OTHER MATERIAL: The type of Sylvilagus nivicola is a specimen collected at 4800 m ‘“‘en el limite de nieves perpetuas’”’ on Cerro Antisana, about 10 km south of Papallacta (Cabrera, 1913: 6). Ten additional specimens of rabbits from Antisana (AMNH 66659— 66668) were subsequently collected between 4115 and 4265 m by H.E. Anthony in 1923. Other material from Antisana (in the BMNH) was reported by Laurie (1955), and a few
VOSS: NEW THOMASOMYS 35
more specimens are scattered among other museums (e.g., MCN, MNCN).
TAXONOMY: All of the material at hand is referable to Sylvilagus brasiliensis in the sense of Hershkovitz (1950), the last com- prehensive taxonomic review of South American lagomorph taxonomy. Hershkovitz (1950) treated nivicola Cabrera (1913) as a valid subspecies of S. brasiliensis, but Laurie (1955) synonymized nivicola with S. b. an- dinus (Thomas, 1897b). The current treat- ment (Hoffmann, 1993) of 41 nominal taxa ranging from southern Mexico to northern Argentina as synonyms or subspecies of S. brasiliensis obviously merits critical scruti- ny, but is far beyond the scope of this faunal report.
REMARKS: Although I did not collect any rabbits near Papallacta, they were abundant in grassy habitats throughout the paramo zone.
DISCUSSION
The discovery less than 50 km east of the Ecuadorean capital of a new species of nu- merically abundant rodent, and the rediscov- ery in the same place of several other species previously known only from type material, indicates how much yet remains to be learned about mammalian diversity and en- demism in the northern Andes. Indeed, the mammalogical exploration of the Cordillera Oriental has hardly begun. The following paragraphs summarize what can be inferred about mammalian faunal composition above 3000 m in these mountains and _ briefly sketches the dimensions of our ignorance about almost everything between this eleva- tion and the Amazonian lowlands to the east.
SAMPLING COMPLETENESS
On 50 sampling days between 8 May 1978 and 7 May 1980, inclusive, I trapped 241 individual small mammals belonging to 16 species near Papallacta. As is typically the case when cumulative species richness is plotted against cumulative captures (fig. 15), new species were encountered at a relatively rapid rate early in the sampling process and at a relatively slow rate in the later stages. In fact, no new species were encountered among the last 102 trapped individuals. Be-
36 AMERICAN MUSEUM NOVITATES
Cumulative Species
0 50 100
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150 200 250
Number of Captures
Fig. 15.
Species accumulation for small mammal trapping near Papallacta, where 16 species of
caenolestid marsupials, shrews, and murid rodents were taken over 50 sampling days in 1978 and 1980 (see text). The stepped appearance of the graph merits comment. Traps were first deployed along streams to capture ichthyomyines, where a total of 11 species were taken after 11 nights; 19 subsequent nights of streamside trapping more than doubled the number of recorded captures but yielded no additional species. The second increase in species richness resulted from moving traplines away from streams onto neighboring hillsides, where five more species were encountered.
cause the traps I used are known to be ef- fective for a wide range of species, and be- cause I made a sustained effort to sample all recognizable macro- and microhabitats above 3000 m, these results suggest that few small (ca. <300 g) nonvolant species remain to be discovered here. Nevertheless, the fact that I did not trap some small species known to occur locally (e.g., Phyllotis haggardi) and the possibility that new species might occur in habitats that I was unable to sample effec- tively (e.g., paramo bogs, marshy lake shores, Upper Montane Rainforest) are com- pelling arguments for continued inventory efforts in the region.
Sampling completeness for the larger fau- na, which I did not systematically attempt to survey, is more difficult to assess because there are no records of the methods and ef- fort used by earlier collectors. However, only five additional species seem likely to occur
locally based on the distributional data com- piled by Tirira (1999): Mazama rufina, Leo- pardus tigrinus, Lontra longicaudis, Nasuel- la olivacea, and Sciurus granatensis.® At least some of these species probably inhabit Upper Montane Rain Forest, a vegetation type that no longer remains intact on acces- sible slopes above 3000 m near Papallacta.
BIOGEOGRAPHIC COMPOSITION
As summarized in this report, the known nonvolant mammalian fauna of the crest of the Cordillera Oriental in northeastern Ec- uador is a distinctive assemblage of several biogeographic groups, including (1) clades with distributions that extend to south-tem- perate latitudes (Pseudalopex, Lynchailurus,
8 This list does not include domesticated (or semido- mesticated) species, such as Cavia porcellus and came- lids, the indigenous status of which seems debatable.
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Hippocamelus, Pudu, Akodon, Phyllotis); (2) clades with distributions that extend to north- temperate latitudes (Cryptotis, Odocoileus, Reithrodontomys); (3) clades with distribu- tions that extend to both south- and north- temperate latitudes (Didelphis, Puma, Cone- patus, Mustela, Sylvilagus); (4) widespread tropical clades (Tapirus, Neusticomys, Coen- dou, Cuniculus); and (5) clades that are en- demic to the tropical Andes (Caenolestes, Tremarctos, Anotomys, Chilomys, Microry- zomys, Thomasomys). At the species level, a substantial fraction of the fauna (17 of 33 species) is endemic to the northern Andes— north of the Huancabamba Deflection in northern Peru—including representatives from all of the groups enumerated above: Caenolestes fuliginosus, Cryptotis montiva- gus, Pudu mephistopheles, Tapirus pinc- haque, Akodon latebricola, Anotomys lean- der, Chilomys instans, Neusticomys monti- colus, Phyllotis haggardi, Thomasomys baeops, T. cinnameus, T. erro, T. paramo- rum, T. rhoadsi, T. silvestris, T. ucucha, and Coendou quichua. Among these northern- Andean endemics, three species are only known from northeastern Ecuador (Akodon latebricola, Thomasomys erro, T. ucucha) and provide some support for the existence of a distinct center of endemism in the Cor- dillera Oriental.
Unfortunately, Akodon latebricola, Tho- masomys erro, and Thomasomys ucucha are each known from so few localities that the geographic limits of any center of endemism they might represent is necessarily specula- tive. However, the lowland gap formed by the headwaters of the Rio Pastaza to the south Gin central Ecuador) and a nother cor- responding to the headwaters of the Rio Ca- queta to the north Gin southern Colombia) seem likely candidates. Volcan Sumaco (fig. 14) is presumably a vicariant part of this en- demic center because its biota is clearly de- rived from the adjacent slopes of the Cordil- lera Oriental (Chapman, 1926; Lgjtnant and Molau, 1982). Also within these hypothetical limits, inter alia, are the Cordillera de los Llanganates (rising from the left bank of the upper Pastaza), the Cordillera El Diviso (in- cluding Volcan Cayambe), the Cordillera de Pimampiro (northeast of Ibarra), and the Pa- ramos de las Juntas (east of Ipiales). Only
VOSS: NEW THOMASOMYS 37
future collecting in these poorly known re- gions will help resolve the currently obscure picture of mammalian montane endemism in northeastern Ecuador and southern Colom- bia.
HORIZONTAL COMPLEMENTARITY: COMPARISONS WITH OTHER HIGHLAND FAUNAS
In terms of higher-taxonomic composition, the nonvolant mammalian fauna near Papal- lacta broadly resembles faunas from other northern-Andean localities, of which the best-sampled is the Cajas Plateau of southern Ecuador (Barnett, 1999). Meaningful com- parisons are possible between Papallacta and Cajas because small nonvolant mammals were intensively trapped at both sites with similar equipment over elevational gradients that each included montane forest, a shrubby ecotone, grassy paramo, and Polylepis thick- ets. Both faunas (table 10) contain caenoles- tid marsupials and shrews, together with ako- dontine, ichthyomyine, oryzomyine, phyllo- tine, and “‘thomasomyine”’ murid rodents; Thomasomys is the most speciose genus at each site.
Despite such methodological, environmen- tal, and higher-taxonomic similarities, these inventories document a surprising degree of species-level complementarity (sensu Col- well and Coddington, 1994). Counting just those small nonvolant mammals recorded above 3000 m, a total of 26 species is rep- resented in the two lists, of which 16 are uniques (occurring at just one site). Colwell and Coddington’s C is therefore 16/26 < 100 = 62% between ecologically comparable sites separated by less than 300 airline km. Although it is possible that additional col- lecting at both sites will discover more shared species, an equally plausible result is the discovery of more uniques. Pending new fieldwork, there is no basis for thinking that 62% is a biased estimate of complementarity from the data at hand.
Defensible quantitative comparisons with other highland faunal inventories are com- plicated by methodological differences, eco- logical disparities, and other problems, but a limited number of studies available for ad hoc inference (Aagaard, 1982; Lo6pez-Arév-
38 AMERICAN MUSEUM NOVITATES
TABLE 10 Nonvolant Small Mammals from Two Well-Sampled Highland Faunas in Ecuador
Papallacta* Cajas>
Caenolestidae Caenolestes caniventer x Caenolestes fuliginosus x Caenolestes tatei¢ xX
Soricidae Cryptotis montivagus x Xx
Muridae: Akodontini Akodon latebricola xX Akodon mollis Xx Xx Akodon orophilus x
Muridae: Ichthyomyini Anotomys leander XxX Chibchanomys orcesi Neusticomys monticolus x
»*
Muridae: Oryzomyini Microryzomys altissimus Xx Microryzomys minutus x Oligoryzomys destructor Oryzomys albigularis¢
x KK OK
Muridae: Peromyscini Reithrodontomys mexicanus Xx
Muridae: Phyllotini Phyllotis andium x Phyllotis haggardi Xx xX
Muridae: Sigmodontini Sigmodon inopinatus xX
Muridae: “Thomasomyines” Chilomys instans Thomasomys aureus Thomasomys baeops Thomasomys cinnameus Thomasomys erro Thomasomys “gracilis” Thomasomys paramorum Thomasomys pyrrhonotus Thomasomys rhoadsi Xx Thomasomys sylvestris »,4 Thomasomys ucucha x
mK OS mK mK
ras ms Pt PS
a Species records based on material examined for this report.
5 Species records from Barnett (1999); the Cajas region lies about 25 km W of Cuenca (2°52’S, 78°54’W) in Provincia Azuay.
¢ Species not recorded above 3000 m elevation.
alo et al., 1993; Cadena and Malagon, 1994; Soriano et al., 1999) suggest that horizontal complementarity at the species level could approach 90% for small nonvolant mammals
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between Andean sites separated by as little as 500—700 km, even in the absence of major habitat discontinuities. Obviously, species turnover on this scale poses a significant challenge for timely inventory work across many thousands of kilometers of high-An- dean landscapes that remain sparsely sam- pled by mammalogists.
VERTICAL COMPLEMENTARITY: COMPARISONS WITH ADJACENT LOWLAND FAUNAS
The mammalian fauna of the Amazonian lowlands of northeastern Ecuador (=1000 m in the provinces of Napo and Sucumbios) in- cludes 80 nonvolant species vouchered by museum specimens or documented by other reliable sources (appendix 2). Although no inventory to date has recorded all of these species from any local community, it is prob- able that most of them are sympatric near the base of the Cordillera Oriental, where an ad- ditional 12 species could also be predicted to occur based on distributional information compiled by Tirira (1999).? Among the most striking differences between this lowland fauna and that of the adjacent highlands (>3000 m) near Papallacta is the sparse rep- resentation or disappearance at the higher el- evation of several speciose lowland clades, including didelphid marsupials, edentates, primates, and caviomorph rodents (table 11). By contrast, carnivores, perissodactyls, artio- dactyls, and murid rodents maintain almost equivalent diversity at both elevations. Caen- olestid marsupials and insectivores are the only higher taxa present in the highlands but not in the lowlands. Overall, these data sug- gest that nonvolant mammalian species rich- ness declines by about 60% from the pied- mont to the crest of the Cordillera Oriental.
The highland fauna near Papallacta, how- ever, is not simply an attenuated version of the adjacent lowland fauna. Only three spe- cies are known to occur at both elevations (Didelphis pernigra, Puma concolor, Sylvi- lagus brasiliensis), so the total number of species represented in these faunas (high-
° Cabassous unicinctus, Priodontes maximus, Myr- mecophaga tridactyla, Atelocynus microtis, Speothos venaticus, Herpailurus jaguarondi, Leopardus tigrinus, L. wiedii, Panthera onca, Galictis vittata, Pteronura brasiliensis, Mazama gouazoubira.
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TABLE 11 Taxonomic Distribution of Nonvolant Mammalian Species Richness at Papallacta and in the Adjacent Amazonian Lowlands of Eastern Ecuador
VOSS: NEW THOMASOMYS he)
TABLE 12 Nonvolant Mammalian Collecting Effort at Three Elevational Intervals in Northeastern Ecuador?
Specimens Papallacta® Lowlands? Interval collected % Effort
Marsupialia Lowlands (<1000 m) 837 67
Caenolestidae 1 0 Middle Elevations (1001-3000 m) 34 3
Didelphidae 1 15 Highlands (>3000 m) 371 30 Insectivora 1 0 : Menarthin 0 6 (9) @ Collecting effort in northeastern Ecuador (Napo and Primates 0 15 Sucumbios) was estimated as the number of nonvolant mam- Canivor 6 (9) 9 (17) malian specimens from each elevational interval (N;) in the Perissodactyla 1 1 computerized databases of AMNH, FMNH, KU, MVZ, Artiodactyla 3 (4) 3 (4) UMMZ, and USNM. The total number of specimen records Rodentia summed over all three intervals (N;) from those sources is
Scinmané 0(1) 3 1242. Percent effort was estimated as (N; + Ny) X 100.
Muridea 17
Caviomorpha‘ 2 Lagomorpha ] volant mammals represented in those data- TOTAL SPECIES: 33 (38) 80 (92) bases are from the adjoining northeastern
« Species counts from records documented in the text of this report; parenthetical counts include expected species for which local records are currently unknown (see text).
b Species counts from appendix 1; parenthetical counts include expected species for which local records are currently unknown (see text footnote 8).
© Caviomorphs include erethizontids, hydrochoerids, cuni- culids, dasyproctids, and echimyids.
lands and lowlands combined) is 33 + 80 — 3 = 110, of which 107 are “‘uniques’’. Col- well and Coddington’s C is therefore 107/ 110 X 100 = 98%. Such high complemen- tarity obviously results from wholesale spe- cies turnover across the intervening middle elevations—between 1000 and 3000 m—of the Cordillera Oriental. Unfortunately, al- most nothing is known about patterns of spe- cies replacement in that interval.
THE UNKNOWN MIDDLE ELEVATIONS
As remarked in the Introduction, most fau- nal sampling in northeastern Ecuador has been done along the crest of the Cordillera Oriental or in the adjacent Amazonian low- lands, not on the intermediate slopes. At- tempting to quantify this historical collecting bias, I compiled Ecuadorean specimen re- cords from six computerized museum data- bases (AMNH, FMNH, KU, MVZ, UMMZ, USNM). A total of 1242 specimens of non-
provinces of Napo and Sucumbios, each of which extends from the crest of the Cordil- lera Oriental to the Amazonian lowlands. Sorting specimen records by elevational in- tervals (=1000 m, 1001—3000 m, >3000 m) resulted in the counts and proportions sum- marized in table 12.
These data clearly indicate that the middle elevations of the Cordillera Oriental remain a virtual terra incognita from the mammalog- ical perspective. Although substantial collec- tions of Ecuadorean material are in museums with uncomputerized catalogs (e.g., BMNH, NHRS), I am not aware that any contain sig- nificant numbers of additional specimens from Napo or Sucumbios collected in the in- terval between 1000 and 3000 m; at most, perhaps a few dozen middle- elevation spec- imens remain uncounted. In effect, two thou- sand vertical meters of densely forested hab- itat have never been sampled effectively by mammalogists in northeastern Ecuador. Just how significant is this collecting hiatus likely to be?
The eastern slopes of the Andes harbor di- verse faunas of amphibians, squamates, and birds, many species of which are known to be endemic to intermediate elevations (Duellman, 1979; Stotz et al., 1996), and there is compelling evidence from elevation- al transects in southern Peru that nonvolant mammals likewise show substantial ende- mism between 1000 and 3000 m (Cadle and
40 AMERICAN MUSEUM NOVITATES
Patton, 1988; Patterson et al., 1998). Unfor- tunately, virtually nothing is known about mid-elevational mammalian endemism in the northern Andes because the same pattern of collecting bias documented in table 12 seems to hold throughout eastern Ecuador and Co- lombia, approximately from 5°S to 8°N. No more than incidental collecting (nothing like sustained attempts at faunal inventory) has been attempted along any elevational transect in this extensive region of eastern-slope for- ests, even along such long-established routes as the road from Bafios to Puyo in Ecuador or the road from Bogota to Villavicencio in Colombia. The result is an elevational band at least 2000 m high and more than 1500 km from south to north that is currently unrep- resented by any significant collections of mammals.
DIRECTIONS FOR FUTURE RESEARCH
There can be few higher priorities for sit- ing new faunal inventory work anywhere in South America than in the middle elevations of the eastern Andes of Ecuador and Colom- bia. Although habitat destruction has been extensive along the few roads that currently descend these slopes, the forest remains un- disturbed by man from timberline to pied- mont in many roadless areas. Cutting trail and siting camps in virgin territory where in- tact mid-elevational faunas can still be sam- pled by transect collecting will not be easy, but ongoing road construction along the base of the Andes will shortly make most eastern- slope valleys accessible to land-hungry col- onists. Such opportunities as now exist may soon be lost to subsequent generations of mammalogists.
The present report establishes a baseline for future inventory efforts in the Cordillera Oriental of northern Ecuador. Due to exten- sive clearing along the road from Papallacta to Baeza, it seems unlikely that mid-eleva- tional forests can be effectively sampled for mammals along this particular route, but bet- ter opportunities may exist in the valley of the Rio Oyacachi to the north, and in the valley of the Rio Antisana/Verdeyacu to the south. A logical starting point for productive collecting would be to establish a base camp at or near the 2000 m contour where small
NO. 3421
field teams could return for several years to explore the effectiveness of different faunal- sampling methods in this logistically chal- lenging region of almost-continuous rainfall. New species and novel insights about equa- torial-montane faunal gradients are certain to reward such initiatives.
ACKNOWLEDGMENTS
Partial financial support for fieldwork at Papallacta in 1978 and/or 1980 was provided by the National Science Foundation (DEB 79-10189), the University of Michigan Mu- seum of Zoology, the American Museum of Natural History, the American Society of Mammalogists, and the Explorer’s Club of New York. In Ecuador, I received advice and logistical support from Fernando Ortiz of the Universidad Catdélica and Miguel Moreno of the Museo Ecuatoriano de Ciencias Natura- les. Sergio Figuerroa, Teodoro Suarez, and Carlos Aguirre helped me obtain the neces- sary collecting and exportation permits from the Ministerio de Agricultura y Ganaderia. Paul Kaarakka and the late Vernon J. Tipton were valued companions in the field. Michael D. Carleton (then at UMMZ) and the late Charles O. Handley, Jr. (at USNM) provided helpful advice with various taxonomic prob- lems during my early efforts to identify the material collected in 1978. Subsequent assis- tance with specimen loans and collection data was rendered by Paula Jenkins (BMNH); Bruce Patterson and Bill Stanley (FMNH); Thor Holmes, Norm Slade, and Bob Timm (KU); Judy Chupasko (MCZ); Jo- sefina Barreiro (MNCN); Olavi Gr6énwall (NHRS); Diego Tirira (QCAZ); and Mike Carleton and Al Gardner (USNM).
Pat Brunauer Gin the AMNH Department of Mammalogy) and Ingrid Lennon (in the AMNH Department of Library Services) provided essential bibliographic assistance in the course of manuscript preparation. All of the craniodental photographs were taken by Peter Goldberg, who also printed the black- and-white photographs taken in the field by me and Paul Kaarakka. Pat Wynne executed the pen-and-ink illustrations in figures 1, 6, 8, and 10 with her customary skill and atten- tion to detail. Nancy Simmons kindly pro- duced figure 15 on her computer. Rob An-
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derson, Marcela G6mez-Laverde, Mike Carleton, and Diego Tirira read the manu- script and offered helpful suggestions for its revision.
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APPENDIX 1
GEOGRAPHIC NOTES
Place names associated with specimens known to have been collected along the old trail from Quito to Baeza are a source of lingering confusion in the zoological literature. In order to better document the provenance of specimens examined for this report, I tried to locate every published first-hand descrip- tion of this journey and the surrounding landscape. Apparently, two alternative routes were formerly used to cross the summit of the Cordillera Oriental and arrive at Papallacta. The following summary may prove helpful for other researchers working with old material from this region.
The only published survey of a route from Qui- to to Baeza appears to be the stadia and plane- table traverse in Sinclair (1929). From the north- eastern outskirts of Quito (0°13’S, 78°30’W) the road to Baeza passed through the towns of Gua- pulo (0°12'S, 78°29'W), Cumbaya (0°12’S,
78°26'W), Tumbaco (0°13’S, 78°24’W), and Pifo (0°14'S, 78°20’W). A short distance beyond Pifo was an hacienda known as Paluguillo (0°15’S, 78°18'W), which was said to be the last perma- nently inhabited place before Papallacta was reached by this route (Sinclair, 1929; Moore, 1934). Leaving Paluguillo (at 9452 ft [2881 m] according to Sinclair), the trail climbed ESE to the northernmost of the two passes referred to in the literature as Guamani (ca. 0°20’S, 78°12’W). From this pass, a broad saddle at 4070 m, the road descended to a lake variously referred to as **Sugchoscocha’”’ (Sinclair, 1929: 205) or ‘‘Lagu- na de Sugchos”’ (op. cit.: pl. 3); on modern maps (e.g., IGM, 1978b) it is labeled as ‘‘Laguna Su- cus’’. The next prominent landscape feature along this route was Laguna Papallacta, from which the trail descended to the town itself (fig. 1).
46 AMERICAN MUSEUM NOVITATES
Nineteenth-century travelers and some 20th century collectors, however, followed another route that crossed the continental divide farther to the south. According to Jiménez de la Espada (1928), whose posthumously published journal described a journey made in 1865, this trail di- verged from the itinerary described above at Tum- baco (0°13’S, 78°24'W), passed through an haci- enda called Itulcache or Itulcachi (0°17'S, 78°20'W), and continued southward and eastward to the small village of Tablon (0°22'S, 78°15’W),. From Tabloén the trail ascended to another pass called Guamani, about 5—6 km SW of the hom- onymous northern pass described above. This southern pass was described by Orton (1870) and Jiménez de la Espada (1928) as a sharp ridge, as it is currently depicted on modern maps (near 0°22'S, 78°14’W) at an elevation of 4150 m (IGM, 1978b). From this high point, the trail de- scended to a tambo (traditional resting place or shelter), probably the spot mapped as Hacienda El Tambo (ca. 0°23’S, 78°12'’W) at 3780 m on the south bank of the Rio Tambo (fig. 1). This south- ern route then converged on the northern road at or near Laguna Papallacta.
The modern all-weather road from Quito to Baeza follows the northern route described above, but does not pass by Laguna Sucus as the old road once did (fig. 1). The southern route is not marked on modern maps but perhaps remains as a foot- path used by herders, fishermen, or hunters. Not knowing of its existence or historical significance, we did not attempt to find it when we worked near Papallacta from 1978 to 1980.
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The literature contains several erroneous refer- ences to various places near Papallacta, especially with regard to the two passes confusingly known as Guamani. Paynter’s (1993) coordinates refer to the northern pass, but his elevation (3600 m) is much too low and at least some of the collectors he lists as working at Guamani (e.g., the Olallas) probably visited the southern pass instead. The distinction is potentially important because the eastern and west- ern approaches and the summit of the northern pass are mostly open paramo, whereas Jameson (1858), Orton (1870), and Jiménez de la Espada (1928) de- scribed the trail to the southern pass as passing through a forest on the western slope. ‘“‘Cerro Gua- mani’, a place name that occurs on several speci- men tags, may refer to a peak that rises to 4277 m between the north and south passes; on modern maps (e.g., IGM, 1978b) it is labeled as ‘“‘Singu- nay’’. Alternatively, Guamani may have been used in a regional sense—for the entire crest of the east- ern cordillera south of Cayambe (0°02’N, 77°59'W) and north of Antisana—as defined by Reiss (1872).
The location of Tabl6n, another source of local specimens, is also problematic. According to Paynter (1993), this place is in Provincia Napo on the eastern slope of the Cordillera Oriental (Payn- ter, 1993), but first-hand accounts by travellers on the southern route describe the spectacular view westward from this point (e.g., Orton, 1870: 179) as well as the subsequent eastward climb to the pass; the coordinates of Tabl6n in modern gazet- teers (e.g., USBGN, 1987) likewise place it at least 3 km west of the continental divide in Prov- incia Pichincha.
APPENDIX 2
NONVOLANT LOWLAND MAMMALS FROM NAPO AND SUCUMBIOS
The following list comprises published and un- published records of mammals collected or ob- served below 1000 m elevation in the provinces of Napo and Sucumbios, both of which extend from the crest of the eastern Andes to the Ama- zonian lowlands of northeastern Ecuador.'° Taxa are listed in the systematic sequence of Wilson and Reeder (1993), but names have been updated to conform with current usage (ICZN, 1998; Mus- ser et al., 1998; Patton et al., 2000; Voss et al.,
'0 Unbeknownst to us when we compiled these re- cords, Napo was recently (1998) divided into two prov- inces: ‘“‘Napo”’ was retained as the name for the western part, but the eastern part is now called “Francisco de Orellana” (D. Tirira, personal commun.). Almost all of our Napo records are from the western half of the old province.
2001). Institutional collections in which voucher material is deposited are listed parenthetically af- ter each Latin binomial. Most voucher material was not examined to confirm identifications, which were obtained secondhand from electronic databases (FMNH, KU, MVZ, UMMZ, USNM), publications on museum holdings (e.g., Cabrera, 1917; Loénnberg, 1913, 1921, 1922; Baker, 1974), and the revisionary literature (Lawrence, 1941; Hall, 1951; Patton, 1987; Voss, 1988; Musser et al., 1998; Voss and da Silva, 2001). Five un- vouchered sightings (marked with asterisks be- low) are included from a 1996 visit to La Selva Jungle Lodge (0°30'S, 76°22'W; in Sucumbios province) by R.S. Voss and L.H. Emmons; sup- porting fieldnotes are preserved in the archives of the AMNH Department of Mammalogy.
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MARSUPIALIA Didelphidae Caluromys lanatus (AMNH, FMNH, KU, MSU, USNM) Chironectes minimus (MSU) Didelphis pernigra (FMNH) Didelphis marsupialis (AMNH, KU, USNM) Glironia venusta (AMNH) Marmosa lepida (KU) Marmosa murina (AMNH, KU) Marmosa rubra (AMNH, FMNH) Marmosops impavidus (AMNH) Marmosops noctivagus (AMNH, KU, MSU, UMMZ, USNM) Metachirus nudicaudatus (AMNH, KU, UMMZ) Micoureus demerarae (FMNH) Micoureus regina (AMNH, MSU, UMMZ) Monodelphis adusta (AMNH) Philander andersoni (AMNH, FMNH, MSU, UMMZ, USNM) XENARTHRA Bradypodidae Bradypus variegatus (FMNH) Megalonychidae Choloepus didactylus (MNCN) Dasypodidae Dasypus kappleri* Dasypus novemcinctus* Myrmecophagidae Cyclopes didactylus (UMMZ) Tamandua tetradactyla (MSU) PRIMATES Callitrichidae Callithrix pygmaea (MNCN, MSU, UMMZ, USNM) Saguinus fuscicollis (AMNH, MNCN) Saguinus nigricollis AMNH, FMNH, KU, MNCN, UMMZ, USNM) Saguinus tripartitus (UMMZ) Cebidae Alouatta seniculus (FMNH, MNCN, MVZ) Aotus vociferans (AMNH, FMNH, KU, USNM) Ateles belzebuth (USNM) Callicebus cupreus (FMNH, MNCN, MSU, UMMZ) Callicebus torquatus (see Torre et al., 1995) Cebus albifrons (FMNH, MVZ, UMMZ) Cebus apella (MNCN, USNM) Lagothrix lagotricha (AMNH, FMNH, MNCN, UMMZ, USNM) Pithecia aequatorialis (AMNH) Pithecia monachus (AMNH, UMMZ) Saimiri sciureus (FMNH, UMMZ) CARNIVORA Felidae Leopardus pardalis (AMNH, FMNH, MSU, MVZ, UMMZ) Puma concolor (AMNH, MSU, MVZ) Mustelidae Eira barbara (AMNH) Mustela africana (MCZ) Lontra longicaudis (FMNH, MNCN, MVZ) Procyonidae Bassaricyon gabbii*
VOSS: NEW THOMASOMYS 47
Nasua nasua (AMNH, FMNH, MSU) Potos flavus (AMNH) Procyon cancrivorus* PERISSODACTYLA Tapiridae Tapirus terrestris (FMNH) ARTIODACTYLA Cervidae Mazama americana (KU, MVZ, UMMZ) Tayassuidae Pecari tajacu (AMNH, MNCN) Tayassu pecari (MVZ) RODENTIA Sciuridae Microsciurus flaviventer (AMNH, FMNH, KU, MSU, UMMZ, USNM) Sciurus igniventris (AMNH, FMNH, MNCN, UMMZ, USNM) Sciurus spadiceus (FMNH, MNCN, UMMZ, USNM) Muridae Ichthyomys stolzmanni (AMNH, BMNH, NHRS) Melanomys robustulus (AMNH, UMMZ) Neacomys spinosus (AMNH, FMNH, UMMZ, USNM) Neacomys cf. tenuipes (MCZ) Nectomys apicalis (AMNH, FMNH, MSU, MVZ, UMMZ, USNM) Oecomys bicolor (AMNH, FMNH, KU, MSU, UMMZ) Oecomys superans (AMNH, FMNH, KU, MVZ) Oligoryzomys cf. fulvescens (KU, UMMZ) Oryzomys macconnelli (AMNH, MCZ) Oryzomys perenensis (AMNH, FMNH, KU, MVZ, UMMZ, USNM) Oryzomys yunganus (AMNH, UMMZ) Rhipidomys leucodactylus (AMNH, FMNH, MVZ, USNM) Scolomys melanops (USNM) Erethizontidae Coendou cf. prehensilis (USNM) Coendou ichillus* Hydrochoeridae Hydrochoeris hydrochaeris (FMNH) Cuniculidae Cuniculus paca (FMNH, MVZ) Dasyproctidae Dasyprocta fuliginosa (AMNH, FMNH, MNCN, MVZ) Myoprocta pratti (AMNH, FMNH, MVZ, UMMZ) Echimyidae Dactylomys dactylinus (KU, MSU, USNM) Echimys saturnus (KU, MSU) Isothrix bistriata (see Tirira, 1999: 141) Makalata sp. (KU) Mesomys sp. (AMNH, USNM) Proechimys cf. brevicauda (AMNH, MVZ, FMNH, UMMZ) Proechimys cf. simonsi (AMNH, KU, MVZ, UMMZ, USNM) Proechimys cf. steerei (MVZ, UMMZ) LAGOMORPHA Leporidae Sylvilagus brasiliensis (FMNH, MSU)
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