INTERRELATIONSHIPS OF POLYDOLOPIDAE (MAMMALIA, MARSUPIALIA) FROM SOUTH AMERICA AND ANTARCTICA

CHORNOGUBSKY, L.

Bristol, Reino Unido

Jornada; 69th Society of Vertebrate Paleontology Annual Meeting; 2009

Universidad de Bristol- SVP

Polydolopinae (Family Polydolopidae Ameghino) is a group of marsupials restricted to the Paleogene of Patagonia in Argentina and Chile, and the Antarctic Peninsula. In order to resolve the interrelationships of polydolopine taxa two unweighted (equally-weighted) parsimony analyses based on dental characters were carried out; one including all widely recognized species and a second one including only species represented by both upper and lower dentitions. In both analyses the following species were used as outgroups: Microbiotherium tehuelchum, Prepidolops didelphoides, Epidolops ameghinoi, and Roberthoffstetteria nationalgeographica. The expanded analysis included: Polydolops thomasi, P. winecage, P. clavulus, P. rothi, P. serra, P. unicus, P. mayoi, P. abanicoi, P. mckennai, P. sp. nov. 1, P. sp. nov. 2, P. sp. nov. 3, Pseudolops princeps, Amphidolops serrula, Amphidolops sp. nov. 1, Amphidolops sp. nov. 2, Antarctodolops dailyi, Antarctodolops mesetaense, Eudolops tetragonus, E. caroliameghinoi, E. hernandezi, Gen. et sp. nov. 1, and Gen. et sp. nov. 2. Polydolops winecage, P. clavulus, P. mayoi, P. abanicoi, P. mckennai, P. sp. nov. 1, P. sp. nov. 2, P. sp. nov. 3, Pseudolops princeps, Eudolops tetragonus, and E. hernandezi were excluded in the reduced analysis. Both analyses argue in favor of the exclusion of Epidolopinae from Polydolopidae. The extended analysis results in a polytomy that contains two clades of polydolopines, one consisting of Amphidolops species + [P. serra, P. rothi, and P. unicus] and another one consisting of Antarctodolops species. The reduced analysis shows a sister-group relationship between Antarctodolops and a clade formed by Amphidolops and the group [P. serra, P. rothi and P. unicus]. The present analyses, which constitute the first cladistic attempt to clarify the relationships of polydolopine taxa, do not support the monophyly of Polydolops as currently understood, whereas, conversely, suggest that Antarctodolops and Amphidolops are natural groups.