DROMICIOPS É MAIS CANGURU OU TIMBU? O QUE DIZEM AS EVIDÊNCIAS MOLECULARES SOBRE A PROXIMIDADE DO MONITO-DEL-MONTE COM OS MARSUPIAIS AUSTRALIANOS E SUL-AMERICANOS

Abstract

Marsupials are primarily found in Australasia and South America, with only one species occurring in North America. The fossil record suggests that the South American order Microbiotheria had a long and widespread existence, ranging from Bolivia to Antarctica. Currently, the sole living representative of the Microbiotheria lineage is Dromiciops gliroides, commonly known as the "monito del monte" or "colocolo". Despite its current restricted distribution to Patagonia and its phenotypic similarity to South American marsupials, both molecular and morphological evidence suggests a closer relationship between D. gliroides and Australian marsupials. To investigate these relationships further, a phylogenetic analysis of 30 terminal taxa (27 genera distributed across 20 families) was conducted using molecular data from the Cyt b gene available in the GenBank database. Maximum Parsimony and Distance Test (UPGMA) analyses were employed. Despite relatively low Bootstrap indices in the phylogenetic trees, the results support the hypothesis of a closer kinship between Dromiciops and Australian marsupials. However, this also sparks debate regarding whether Australidelphia and Ameridelphia share a common ancestor. Molecular data analyses suggest that Australidelphia is a paraphyletic group, encompassing clades of American marsupials, while Dromiciops and Caenolestes are related to different clades of Australian marsupials.