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

Abstract

ABSTRAGr.-Protein variation at 30 presumptive gene loci was examined among 36 populations comprising all species of spiny pocket mice (subfamily Heteromyinae). The bulk of betweensample 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 HeteTomys 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 HeteTomys. Genic and karyotypic data indicate that H. desmaTestianus is divisible into two moieties in southern Mexico, H. goldmani is not differentiated from geographically adjacent populations of H. desmaTestianus, and H. OTesteTus is not closely allied with H. nelsoni. Based on allozyme data, H. anomalus and H. austTalis 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 gwerally accepted view of a recent invasion of South America by these mice.Spiny pocket mice of the heteromyid subfamily Heteromyinae (genera HeteTomys and Liomys-Honacki et aI., 1982) are a group in which morphological parallelism is widespread (Wood, 1935). Fossil remains are known from Pliocene, Pleistocene, and Holocene depositions but are indistinguishable from extant forms (Alvarez, 1982;Wood, 1935). Morphological variation within the subfamily is fairly well documented, and the view that heteromyines form a monophyletic lineage has never been contested. Among the morphological characters distinguishing Heteromys and Liomys from other heteromyids are several shared derived characters of the glans penis (Hafner and Hafner, 1983), exomorphology (Wood, 1935), and hair microstructure (Homan and Genoways, 1978). Genoways (1973) reduced the number of species in the genus Liomys from 11 to five, dividing these into three groups as follows: L. irroratus, L. pictus and L. spectabilis, and L. salvini and L. adspersus. In his revision, Goldman (1911) recognized 13 species of Heteromys, dividing them among two subgenera (Heteromys and Xylomys). He further divided the nominate subgenus into two species groups, anomalus and desmarestianus. Rogers and Schmidly (1982) evaluated the systematic relationships of H. desmarestianus, H. lepturus, H. longicaudatus, H. goldmani, and H. temporalis by examining variatio...

Phylogenetics of the New World Rodent Family Heteromyidae

“…It is possible that this group represents an independent lineage with no close living relatives (Hafner 1978(Hafner , 1993). In addition, it has been suggested that Heteromys is paraphyletic relative to Liomys (Rogers 1990). Our sampling of Heteromys and Liomys is insufficient to address this question and it is being addressed elsewhere (D. Rogers, pers.…”

Liomys spectabilis

“…Six centric fusions and 1 pericentric inversion (Robertsonian events) can explain the derivation of the karyotype of L. spectabilis from the ancestral lineage of L. irroratus, and 1 additional pericentric inversion produces the karyotype of L. pictus (Genoways 1973). Chromosomal polymorphism of L. pictus suggests that both species are sister taxa, and both are equally related with L. irroratus (Rogers 1990). A vicariant event is proposed to explain the separation between L. p. pictus and L. spectabilis (Rogers and Engstrom 1992), supporting the hypothesis by homologing the G-bands of both species (Cervantes et al 1999).…”

Liomys adspersus

“…ically (Genoways 1973), and genetically (Rogers 1990) closely related to L. salvini, whose range ends 300 km to the north of that of L. adspersus. L. salvini and L. adspersus are placed together in the salvini group (Genoways 1973).…”