Reithrodontomys (Reithrodontomys) megalotis (Baird 1857) [Reithrodon] megalotis Baird 1857, Mammalia, in: Repts. U. S. Expl. Surv., Vol. 8, 1: 451. Type Locality: México-USA boundary region, between Janos, Chihuahua, and San Luis Springs, Grant Co., New Mexico. Vernacular Names: Western Harvest Mouse. Synonyms: Reithrodontomys (Reithrodontomys) alticolus Merriam 1901; Reithrodontomys (Reithrodontomys) amoles A. H. Howell 1914; Reithrodontomys (Reithrodontomys) arizonensis J. A. Allen 1895; Reithrodontomys (Reithrodontomys) aztecus J. A. Allen 1893; Reithrodontomys (Reithrodontomys) caryi A. H. Howell 1935; Reithrodontomys (Reithrodontomys) catalinae (Elliot 1904); Reithrodontomys (Reithrodontomys) cinereus Merriam 1901; Reithrodontomys (Reithrodontomys) deserti J. A. Allen 1895; Reithrodontomys (Reithrodontomys) distichlis von Bloeker 1937; Reithrodontomys (Reithrodontomys) dychei J. A. Allen 1895; Reithrodontomys (Reithrodontomys) hooperi Goodwin 1954; Reithrodontomys (Reithrodontomys) klamathensis Merriam 1899; Reithrodontomys (Reithrodontomys) limicola von Bloeker 1932; Reithrodontomys (Reithrodontomys) longicaudus (Baird 1857); Reithrodontomys (Reithrodontomys) nebrascensis J. A. Allen 1895; Reithrodontomys (Reithrodontomys) nigrescens A. H. Howell 1914; Reithrodontomys (Reithrodontomys) pallidus Rhoads 1893; Reithrodontomys (Reithrodontomys) pectoralis Hanson 1944; Reithrodontomys (Reithrodontomys) peninsulae (Elliot 1903); Reithrodontomys (Reithrodontomys) ravus Goldman 1939; Reithrodontomys (Reithrodontomys) santacruzae Pearson 1951; Reithrodontomys (Reithrodontomys) saturatus J. A. Allen and Chapman 1897; Reithrodontomys (Reithrodontomys) sestinensis J. A. Allen 1903. Distribution: SC British Columbia and SE Alberta, Canada; through much of W and NC USA; south to N Baja California Norte and through interior México to C Oaxaca. Conservation: IUCN – Lower Risk (lc). Discussion: Subgenus Reithrodontomys, megalotis species group. Formerly included R. zacatecae, which Hood et al. (1984) identified as a separate species. The substantial chromosomal variation reported (see Engstrom et al., 1981) cautions that yet other species are lumped under R. megalotis. Multivariate discrimination from R. montanus in Kansas demonstrated by Hoofer et al. (1999). Recent range expansions into NE Illinois (see Pigage and Pigage, 1994) and within N Texas (Yancey and Jones, 1997) reported; L. Choate (1997) discussed the clinal intergradation between the subspecies aztecus and megalotis on the Llano Estacado, Texas-New Mexico; southern range extension on Baja Peninsula reported by Rios and Alvarez-Castañeda (2002). See Webster and Jones (1982, Mammalian Species, 167).

Published as part of Wilson, Don E. & Reeder, DeeAnn, 2005, Order Rodentia - Family Cricetidae, pp. 955-1189 in Mammal Species of the World: a Taxonomic and Geographic Reference (3 rd Edition), Volume 2, Baltimore :The Johns Hopkins University Press on page 1082, DOI: 10.5281/zenodo.7316535