Oligoryzomys microtis J. A. Allen 1916

Wilson, Don E. & Reeder, DeeAnn, 2005, Order Rodentia - Family Cricetidae, Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 2, Baltimore: The Johns Hopkins University Press, pp. 955-1189 : 1143

Oligoryzomys microtis J. A. Allen 1916

Oligoryzomys microtis J. A. Allen 1916 , Bull. Am. Mus . Nat. Hist., 35: 525.

Type Locality: Brazil, Amazonas State, north bank of lower Rio Solimões, 70 km WSW Manaus, Manacaparú (as restricted by Voss et al., 2001:118-119).

Vernacular Names: Small-eared Colilargo.

Synonyms: Oligoryzomys chaparensis (Osgood 1916) ; Oligoryzomys mattogrossae (J. A. Allen 1916) .

Distribution: Amazon Basin of Brazil and contiguous lowlands of Perú, Bolivia, and Paraguay.

Conservation: IUCN – Lower Risk (lc).

Discussion: Karyotype reported by Gardner and Patton (1976) as Oryzomys longicaudatus variant (2) for Peruvian sample; slightly different diploid and fundamental numbers documented for specimens from Amapá, Brazil ( Andrades-Miranda et al., 2001 a). Gene sequence analyses indicate that O. microtis and O. fornesi represent separate species groups ( Myers et al., 1995), not populations of a single species ( Carleton and Musser, 1989; Olds and Anderson, 1987). With removal of fornesi from synonymy and fixation of the type locality, specific definition and distributional limits require amendment; also see Voss et al. (2001) for comparisons with O. fulvescens and comments on taxonomy.