Morphometric Differentiation and Taxonomy of Three Chromosomally Characterized Groups of Peromyscus boylii from East-Central Mexico

Abstract

Morphometric characters are congruent with cytogenetic and genic evidence in dividing Peromyscus boylii into three groups in east-central Mexico. These include a monomorphic, low-FN group (FN = 52); a polymorphic, low-FN group (FN = 52–54); and a polymorphic, high-FN group (FN = 58–60). Univariate and multivariate analyses of morphometric features discriminate the three groups, with the overall pattern more evident in the multivariate than the univariate approach. Some of the qualitative characters show the monomorphic low-FN specimens to be distinct from the karyotypically polymorphic groups, but none of them is diagnostic. Morphometric comparisons of the three karyotypic groups with topotypic and reference samples of the recognized taxa of P. boylii in Mexico support the following taxonomic assignments for these forms: monomorphic, low-FN group, P. boylii rowleyi ; polymorphic, low-FN group, P. beatae ; and the polymorphic, high-FN group, P. levipes . The three chromosomal groups appear to represent a good example of cryptic species.