We analyzed morphometric and molecular variation among 8 populations of Peromyscus zarhynchus grouped into 5 pooled samples representing separate physiographic regions across the range of this species in Chiapas, Mexico, and western Guatemala. Mitochondrial sequence data identify 2 well-supported and reciprocally monophyletic clades, separating all Chiapas specimens from those in Guatemala. These 2 clades group as a strongly supported monophyletic lineage aligned with other members of the Peromyscus mexicanus species group. The Chiapas clade is further subdivided into 4 subclades: 1) samples from the western part of the state, 2) specimens from a single locality in Northern Chiapas, 3) all central localities, and 4) those from a single locality in Eastern Chiapas. The molecular distance in the mitochondrial cytochrome-b gene (Cytb) between the 2 major clades is relatively low (mean p-distance = 3.66%); those between the 4 Chiapas subclades are even less (mean p-distance 2.73%). Multivariate analyses of external and craniodental morphometric variables also distinguish 2 major groups, separating Guatemalan from Chiapas samples but with the latter also divided into 2 subgroups, one that segregates the Northern Chiapas sample from those distributed elsewhere in that state. The Guatemalan and Chiapas samples differ in both cranial size and shape variables. The second-level separation of samples from within Chiapas (northern versus all others) is interpreted to result from the combination of local adaptation to distinct physiographic regions and geographic isolation generated by patches of suitable habitat. We describe the Guatemalan samples as a distinct species based on their molecular and morphological uniqueness, and argue that P. zarhynchus itself is divided into definable subspecies, with the nominotypical form P. z. zarhynchus, restricted to the vicinity of its type locality (Tumbalá) in Northern Chiapas, and P. z. cristobalensis with type locality of San Cristobal, over the remainder of the species range in the state.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 97 • No. 3