title: Molecular phylogeny of short-tailed opossums (Didelphidae: Monodelphis): taxonomic implications and tests of evolutionary hypotheses.
abstract: Short-tailed opossums (genus Monodelphis) represent one of the most speciose clades of New World marsupials, with 26 currently recognized species that collectively range from eastern Panama to northern Argentina. Here we present the first phylogenetic analyses of the genus based on dense taxonomic sampling and multiple genes. From most sampled species we obtained >4800bp of DNA sequence from one mitochondrial gene (CYTB), two autosomal exons (IRBP exon 1, BRCA1 exon 11), one autosomal intron (SLC38 intron 7), and one X-linked intron (OGT intron 14). Maximum-parsimony, maximum-likelihood and Bayesian analyses of these data strongly support the monophyly of Monodelphis and recover six major clades within the genus. Additionally, our analyses support previous suggestions that several nominal taxa are synonyms of other species (M. "sorex" of M. dimidiata, M. "theresa" of M. scalops, M. "rubida" and M. "umbristriata" of M. americana, and M. "maraxina" of M. glirina). By contrast, four unnamed lineages recovered by our analyses may represent new species. Reconstructions of ancestral states of two discrete characters-dorsal pelage color pattern and habitat-suggest that the most recent common ancestor of Monodelphis was uniformly colored (with unpatterned dorsal pelage) and inhabited moist forest. Whereas some dorsal pelage patterns appear to have evolved homoplastically in Monodelphis, dorsal stripes may have had a unique historical origin in this genus.
authors.affiliation: Department of Biology, City College of New York, City University of New York, New York, NY 10016, USA; Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History, Central Park West at 79th St., New York, NY 10024, USA. Electronic address: silviaeopavan@gmail.com.
authors.forename: Silvia E
authors.initials: SE
authors.lastname: Pavan
authors.affiliation: Department of Ecology, Evolution, and Behavior, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA; J.F. Bell Museum of Natural History, University of Minnesota, 1987 Upper Buford Circle, St. Paul, MN 55108, USA. Electronic address: jansa003@umn.edu.
authors.forename: Sharon A
authors.initials: SA
authors.lastname: Jansa
authors.affiliation: Division of Vertebrate Zoology (Mammalogy), American Museum of Natural History, Central Park West at 79th St., New York, NY 10024, USA. Electronic address: voss@amnh.org.
authors.forename: Robert S
authors.initials: RS
authors.lastname: Voss
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics; D005091:Exons; D050259:Genes, Mitochondrial; D007438:Introns; D016013:Likelihood Functions; D008957:Models, Genetic; D048309:Monodelphis / Q000033:anatomy & histology / Q000145:classification* / Q000235:genetics; D010802:Phylogeny; D017422:Sequence Analysis, DNA
keywords: Mammal; Marmosini; Marsupial; Neotropical; mtDNA; nDNA