A New Species of Thomasomys (Rodentia: Muridae) from Eastern Ecuador, with Remarks on Mammalian Diversity and Biogeography in the Cordillera Oriental Author VOSS, ROBERT S. text American Museum Novitates 2003 2003-12-09 3421 1 48 http://www.bioone.org/doi/abs/10.1206/0003-0082%282003%29421%3C0001%3AANSOTR%3E2.0.CO%3B2 journal article 10.1206/0003-0082(2003)421<0001:ANSOTR>2.0.CO;2 f4c2f80e-4917-4b5b-9415-0ee6377973ce 0003-0082 4734917 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 distinctive genus Chilomys Thomas (1897a) is currently thought to contain only a single valid species, C. instans ( Thomas, 1895b ) ; another nominal taxon, fumeus Osgood (1912) is either a subspecies or synonym according to Cabrera (1961) and Musser and Carleton (1993) . The Papallacta specimens closely resemble the holotype of instans (BMNH 95.10.14.1, from Bogota´) in qualitative characters, but they have slightly broader interorbits and shorter molar rows. A revision of this long­neglected northern­Andean endemic genus is necessary in order to evaluate the taxonomic significance of character variation among these and other specimens from Ecuador , Colombia , and western Venezuela . FIELD OBSERVATIONS : The three specimens of Chilomys instans that I collected near Papallacta 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 páramo/ forest ecotone .