Genic Evolution, Historical Biogeography, and Systematic Relationships Among Spiny Pocket Mice (Subfamily Heteromyinae)

Abstract

Protein variation at 30 presumptive gene loci was examined among 36 populations comprising all species of spiny pocket mice (subfamily Heteromyinae). The bulk of between-sample genic variation involved fixed allelic differences. A distance-Wagner tree divided the heteromyines into two groups, one formed by Heteromys gaumeri and the other composed of all remaining taxa. Within this latter group, species of Heteromys comprising the anomalus species group were genically most similar to members of the genus Liomys . A consensus distance-Wagner tree constructed by use of the jackknifing approach yielded eight unresolved lineages of heteromyines. Genic data support the monophyly of heteromyines relative to other heteromyid rodents, but do not support monophyly of Heteromys and Liomys . Allozyme data were mostly concordant with karyotypic data, but failed to support recent taxonomies based on morphological characters regarding interspecific relationships among species of Heteromys . Genic and karyotypic data indicate that H. desmarestianus is divisible into two moieties in southern Mexico, H. goldmani is not differentiated from geographically adjacent populations of H. desmarestianus , and H. oresterus is not closely allied with H. nelsoni . Based on allozyme data, H. anomalus and H. australis are not closely related. Affinities among species of Liomys derived from allozyme data were in agreement with those based on morphological and chromosomal information, but indicate that L. pictus , as currently constituted, is paraphyletic. The amount of genic divergence within Heteromys from South America most likely precludes the generally accepted view of a recent invasion of South America by these mice.