East African Arvicanthis

discussion

Discussion: 2 n = 62, FN = 78 (Castiglia et al., 2003 a; Fadda et al., 2001). The name nairobae is the oldest applicable to samples from Kenya and E Tanzania containing animals smaller in body size and generally brighter and buffier in pelage tones and hues than those larger and darker specimens we have identified as A. niloticus from W Tanzania and Uganda. Some specimens of A. nairobae closely resemble those of A. neumanni in pelage coloration, and could be mistaken for it, but are larger in body size. Corbet and Yalden (1972) even suggested that chanleri might represent A. neumanni (they used somalicus), but the holotype is larger and fits within the range of variation seen among samples of A. nairobae (our study of holotypes and larger samples in AMNH, BMNH, and USNM). Records of sympatry between A. nairobae and A. neumanni are documented by series from Mount Lololokwi (" an isolated mountain east of the Mathews Range, about midway between Mount Kenia and Mount Marsabit, " Hollister, 1919; specimens in USNM), and the Dodoma region of Tanzania (samples in AMNH), and the two are probably broadly sympatric throughout their ranges in Kenya and Tanzania. The morphological and geograp

Order Rodentia - Family Muridae

distribution

Distribution: Recorded from S Ethiopia (Sidamo) through Kenya in the Rift Valley south to the Dodoma region in EC Tanzania; western and southern limits unresolved (based largely upon our study of specimens; the Ethiopian record and some specimens from W Kenya were identified using discriminant function analysis by Fadda and Corti, 2001). An unidentified sample of Arvicanthis from SW Uganda clusters with Tanzanian samples of A. nairobae in the analysis of mtDNA cytochrome b sequences by Ducroz et al. (1998), which indicates the species may range farther west than described here.

Order Rodentia - Family Muridae

discussion

COMMENTS: The name nairobae is the oldest applicable to samples from east of the Rift Valley in Kenya and Tanzania containing animals smaller in body size and gererally brighter and buffier in pelage than those larger and darker specimens we have identified as A. niloticus from west of the Rift. Some specimens of A. nairobae closely resemble those of A. somalicus in pelage coloration, and might be mistaken for it, but are larger in body size. Corbet and Yalden (1972) even suggested that chanleri might represent somalicus, but the holotype is larger and fits within the range of variation seen among samples of nairobae. Records of sympatry between nairobae and somalicus are documented by series from Mount Lololokwi (specimens in the National Museum of Natural History), and the Dodoma region of Tanzania (samples in the American Museum of Natural History), and the two are probably broadly sympatric throughout their ranges in Kenya and Tanzania. The morphological and geographic relationships between A. nairobae and A. niloticus require resolution, which could be accomplished by systematic review of the niloticus-nairobae complex. For example, nairobae is found with A. somalicus in the D

Order Rodentia - Family Muridae

distribution

DISTRIBUTION: Recorded in and east of the Rift Valley from Mount Lololokwi (" an isolated mountain east of the Mathews Range, about midway between Mount Kenia and Mount Marsabit, " Hollister, 1919) in C Kenya south to the Dodoma region in EC Tanzania; N and S limits unknown.

Order Rodentia - Family Muridae