Abstract
Karyotypic data from a total of 574 deer mice from insular populations off British Columbia and Washington indicate the presence of two distinct karyotypic groups, a "low FN" group (FN = 74-78) and a "high FN" group (FN = 85-92). The absence of karyotypic intermediates at nine localities of sympatry is interpreted as demonstrating that the two FN groups represent distinct species. The low FN form is considered to represent the currently recognized taxon P. maniculatus. Based on Karyotypic and morphologic similarities, the "high FN" form is suggested to be conspecific with P. oreas currently recognized only from the adjacent mainland. Chromosomal banding data indicate the presence of extensive chromosomal variation within each of these species and provide discrete karyotypic characters unique to each of the two species. Analyses of standard external measurements were consistent with the karyotypic dichotomy and revealed significant differences in total length, tail length, body length, and hind foot length between the species. Morphologically based identification schemes allow species determination for specimens for which karyotypic data are not available. The evolutionary origin and subsequent pattern of evolution of the "high FN" form is discussed for all deer mouse taxa occurring along coastal Washington, British Columbia, and Alaska.
Gunn, Scott Jeter (1986). Chromosomal evolution and its systematic implications among insular populations of Peromyscus from Washington State and British Columbia, Canada. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -23593.