FIG. 74 in Model-based analysis of postcranial osteology of marsupials from the Palaeocene of Itaboraí (Brazil) and the phylogenetics and biogeography of Metatheria

FIG. 74. — Simplified phylogeny of the taxa (thick vertical bars) and the hypothesized lineages leading to them (dashed lines). Numbered thick vertical arrows show points on the phylogeny where the stem of the various groups can be identified by diagnostic traits with respect to their ancestry. Only the entry of the stem of Sudameridelphia (1) is problematic in this regard because archaic metatherians outside of South America are less well known. Point 4 stands for the last common ancestor of Australidelphia, derivable from a bona fide didelphid (see text). Point 6 is the putative ancestry of the Gondwanadelphia, and as such it is queried. Thinner, and close to horizontal, arrows indicate both direction of phyletic derivations, as well as the direction of geographical dispersal. Note derivation and dispersal of australidelphians from a South American didelphid stem to Antarctica-Australia.