The characterization of the different taxa of the highly diverse genus Monodelphis is poorly understood, as is the case of their distribution. Historically, taxonomic studies of Monodelphis have been restricted to a few or single species, whereas molecular approaches have been used for estimating phylogenetic relationships between species. We carried out phylogenetic analyses of 14 Monodelphis species, including Monodelphis domestica, based on cytochrome b mitochondrial DNA sequences. Forty-five complete (1149 bp) sequences of this gene were obtained from 39 specimens of M. domestica collected in 23 localities of the Brazilian Cerrado, Pantanal, and Caatinga morphoclimatic domains; one of Monodelphis umbristriata, two of Monodelphis americana, and two of Monodelphis dimidiata. A total of 72 haplotypes were analyzed, 48 only in M. domestica. Analyses were carried out in conjunction with 46 other sequences retrieved from GenBank, including M. domestica, Monodelphis brevicaudata, Monodelphis glirina, Monodelphis emiliae, Monodelphis peruviana, Monodelphis osgoodi, Monodelphis handleyi, Monodelphis kunsi, Monodelphis americana, Monodelphis dimidiata, Monodelphis iheringi, Monodelphis reigi, andMonodelphis adusta, with six other different didelphid species used as outgroups. Maximum likelihood and Bayesian inference were similar in depicting phylogenetic relationships of different Monodelphis taxa. Two clades of M. domestica were defined on the basis of these results. Genetic distance estimates ranged from 3.2% to 6.2% between these clades of M. domestica. Population analyses were carried out to infer the likely demographic scenarios and the relationship between M. domestica haplotypes. Median-joining and spatial analyses showed two populations related to different morphoclimatic domains (Cerrado/Pantanal and Caatinga). These results indicate a population structure in M. domestica and the possibility that this taxon might represent a species complex.

New records for Monodelphis glirina, a short-tailed opossum distributed throughout the Amazon region, from Humaitá, Amazonas state, and Confresa, Mato Grosso state, prompted new insights into the geographic distribution and genetic diversity of this species. One of the records extends the species range circa 350 km beyond the previous southeastern limit. Voucher specimens had their identification confirmed by morphological comparison with the holotype and corroborated by molecular data (mitochondrial gene Cytochrome b). Our analyses revealed an east-west geographic structure into two clades that could represent distinct species, M. glirina and M. maraxina. Furthermore, examination of the holotype brought to light that it was never formally linked with the voucher specimen collected by Johann Natterer.

No abstract

No abstract