Late Cretaceous sudamericid gondwanatherians from India with paleobiogeographic considerations of Gondwanan mammals

ABSTRACT

Gondwanatherians are a distinctive Cretaceous radiation of Gondwanan mammals. Fieldwork in the intertrappean beds of Karnataka and Andhra Pradesh, India has yielded a substantial collection of Maastrichtian mammals, including nine isolated teeth that represent at least two sudamericid gondwanatherians. We name a new taxon, Dakshina jederi, to which we refer six of the specimens and a previously unnamed form (VPL/JU/NKIM/25). The remaining specimens are identified as Gondwanatheria indeterminate. India's Late Cretaceous mammal fauna includes eutherians, a haramiyidan, and sudamericids. Whereas the eutherians likely represent a dispersal event from Laurasia and the haramiyidan represents a relictual distribution on Gondwana, the gondwanatherians are members of an endemic Gondwanan radiation. The sudamericid Dakshina possesses several derived features that suggest phylogenetic affinities with Lavanify from the Maastrichtian of Madagascar and to a lesser extent with Sudamerica from the Paleocene of Argentina. This pattern of phylogenetic relationships agrees with paleogeographic reconstructions for the breakup of Gondwana that hypothesize close biogeographic ties among India, Madagascar, and South America; however, gaps in our temporal and geographic sampling limit our understanding of biogeographic ties that India shares with Africa, Antarctica, and Australia.