Thomasomys paramorum Thomas, 1898

VOSS, ROBERT S., 2003, A New Species of Thomasomys (Rodentia: Muridae) from Eastern Ecuador, with Remarks on Mammalian Diversity and Biogeography in the Cordillera Oriental, American Museum Novitates 3421, pp. 1-48 : 32

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 ‘‘El Tambo, Papallacta 12,000 ft’’ by L. Söderström 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 Söderström specimens (AMNH 46629, 46630, 46634, 46641, 46642) are labeled ‘‘Cuyuco [probably Cuyuja] below Papallacta, 7000 ft’’.

TAXONOMY: The type material of Thomasomys paramorum consists of a single specimen 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 topotypes average larger than the Papallacta sample in most measurements and have proportionately narrower zygomatic plates ( table 7), the two series are similar in qualitative external and craniodental traits and appear to represent the same taxon. No synonyms of T. paramorum are currently recognized.

FIELD OBSERVATIONS: I recorded 29 captures of Thomasomys paramorum near Papallacta 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 páramo, and 7 in the shrubby páramo/ forest ecotone. Twenty­two 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.

Figures

Fig. 11. Dorsal cranial views of eight Thomasomys species that occur in the Cordillera Oriental of northern Ecuador. Top row (left to right): T. aureus (UMMZ 127114), T. baeops (UMMZ 155708), T. cinnameus (UMMZ 155671), T. erro (UMMZ 155713). Bottom row (left to right): T. paramorum (UMMZ 155737), T. rhoadsi (AMNH 66256), T. silvestris (USNM 513592), T. ucucha (UMMZ 155644).

Fig. 12. Ventral cranial views of eight Thomasomys species from the Cordillera Oriental of northern Ecuador. Top row (left to right): T. aureus (UMMZ 127114), T. baeops (UMMZ 155708), T. cinnameus (UMMZ 155671), T. erro (UMMZ 155713). Bottom row (left to right): T. paramorum (UMMZ 155737), T. rhoadsi (AMNH 66256), T. silvestris (USNM 513592), T. ucucha (UMMZ 155644).

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), T. cinnameus (UMMZ 155671), T. erro (UMMZ 155713). Right column (top to bottom): T. paramorum (UMMZ 155737), T. rhoadsi (AMNH 66256), T. silvestris (USNM 513592), T. ucucha (UMMZ 155644).