Consuelo Lorenzo

Genetic variation in Heteromys nelsoni (Rodentia: Heteromyidae) reveals its possible natural extinction

Abstract Heteromys nelsoni is restricted to cloud forests in the mountain range of the southern state of Chiapas, Mexico, and western Guatemala. It is considered an endemic species, under special protection, and endangered because its habitat has been modified by excessive logging and extensive cattle grazing. We evaluated the genetic variation of H. nelsoni and the relationship between individuals from two geographic areas surrounding Cerro Mozotal, Chiapas, using three mitochondrial genes [cytochrome b (Cyt b), cytochrome c oxidase subunit 1 (COI), and control region (D-Loop)]. Low genetic diversity (d<0.9, π<0.005) and average divergence (<0.6%) in mtDNA were observed among the specimens examined. The haplotypes are distributed throughout the areas sampled; therefore, no areas where individuals showed genetic identity, with exclusive haplotypes, were found. Heteromys nelsoni populations have undergone a very recent demographic contraction and the low genetic diversity observed indicates an unfavorable future for the species. Changes in the climatic conditions coupled with other anthropogenic pressures have likely reduced the optimal habitat area for the species. It is imperative to develop programs aiming to reduce the probable risk of extinction of this species.

Noteworthy records of an endemic shrew from Mexico (Mammalia, Soricomorpha, Cryptotis griseoventris), with comments on taxonomy

Abstract The broad-clawed shrew Cryptotis griseoventris Jackson, 1933, is poorly known ecologically and behaviorally because distributional records are relatively scarce. Here, we provide new records based on 11 specimens deposited in mammal collections, more than 50 years since the last confirmed record. Historical records and specimens are reexamined and discussed. We suggest that C. griseoventris occurs in a small area (<5000 km2) above 2100 m dominated by pine oak and cloud forests in Los Altos de Chiapas, Mexico, and is likely endangered due to habitat deforestation. We also describe the humerus, a useful structure to delimit species and reconstruct phylogenetic relationships within the genus Cryptotis. The morphology of their humerus corroborates its taxonomic relatedness with the Cryptotis goldmani species group and yields a more comprehensive knowledge of the ecology and evolution within this group.