Dipodomys ordii

Abstract: Interspecific morphometric variation among 19 species of kangaroo rats (genus Dipodomys) was examined using discriminant-function analysis. Discriminant functions I, II, and III accounted for 53.0, 18.3, and 12.6%, respectively, of the discrimination in males, and 48.9, 19.7, and 13.0%, respectively, of the discrimination in females. Geographic samples were classified to the correct species for 99.6% of the samples. Magnitude of intraspecific variation was related to the size of a species' geographic distribution. Samples segregated into three major aggregations. The first contained the majority of taxa and consisted of smaller species. The second aggregation comprised most of the larger taxa (D. ingens, D. nelsoni, D. spectabilis). Samples of D. deserti were the sole members of the third aggregation. Morphologically similar taxa often were allopatric (e.g., D. californicus, D. elator, D. heermanni, D. panamintinus, D. phillipsii) or had different microhabitat preferences where syntopic (e.g., D. merriami, D. ordii). Other taxa that had generally similar body sizes and overlapping geographic distributions were morphometrically distinct (e.g., D. microps and D. ordii, D. merriami and D. microps, D. compactus and D. ordii). These more subtly defined morphometric differences probably are reflections of adaptations allowing superficially similar species to occupy the same geographic region.

Reference

George D. Baumgardner, Michael L. Kennedy, Patterns of Interspecific Morphometric Variation in Kangaroo Rats (Genus Dipodomys), Journal of Mammalogy, Volume 75, Issue 1, 18 February 1994, Pages 203–211, https://doi.org/10.2307/1382252