MOSASAURS FROM THE JAMES ROSS BASIN, ANTARCTICA

FERNANDEZ, M.; MARTIN, J,E,; TALEVI, M. AND M. REGUERO

Buenos Aires

Conferencia; Open Science Conference SCAR2010; 2010

 Mosasaurs were  diverse  and  specialized Cretaceous  squamate  reptiles  adapted  to marine  life.  Although  mosasaur  record  is  diverse  and  abundant  worldwide,  and  the knowledge of  the group  improved during  the  last years,  there are certain geographic areas and stratigraphic horizons  in which  the  records are still scarce. Many  years of cooperative explorations and researches of the División Paleontología Vertebrados (Museo de La Plata, Argentina)  and  the  Instituto  Antártico  Argentino    (IAA),  Argentina,  result  in  a  collection  of mosasaur materials  from  James  Ross  Basin  (NE  of  the  Antarctic  Peninsula)  that  it  is  of special  interest. Campanian and Maastrichtian mosasaurs have been recovered  from Santa Marta Formation on James Ross  Island, and  from López de Bertodano Formation on Vega and Seymour Islands.  Systematic analysis on these materials demonstrated the presence of tylosaurine  mosasaurs  in  the  Campanian,  and  the  co-occurrence  of  mosasaurines, tylosaurines,  and  plioplatecarpines  in  the Maastrichtian  of  James  Ross  Basin.  Of  special interest is the closely phylogenetic relationship of the tylosaurine Taniwhasaurus antarcticus, from  the  Late  Campanian  of  James  Ross  Island,  with  tylosaurines  from  the  middle Campanian of New Zealand. Analyses of bone microstructure permit  to explore  interesting aspects of mosasaur ecology.   Mosasaurs exhumed  from  the Fm. López de Bertodano on Seymour  Island exhibit  two different bone microstructures. This  fact suggests  that Antarctic mosasaurs could have partitioned the water column.