Meeting Abstract

 

50-6  Saturday, Jan. 5 11:30 – 11:45  The Earliest Equatorial Record of Anurans: New Fossils from the Late Triassic of Arizona STOCKER, MR*; NESBITT, SJ; KLIGMAN, BT; PALUH, DJ; BLACKBURN, DC; MARSH, AD; PARKER, WG; Virginia Tech; Virginia Tech; Virginia Tech; Florida Museum of Natural History, University of Florida; Florida Museum of Natural History, University of Florida; Petrified Forest National Park; Petrified Forest National Park stockerm@vt.edu

Crown-group anurans originated more than 200 million years ago, though only a few fossils from high latitudes chronicle the first 60 million years of their evolution and distribution. We report fossils that represent the first anurans known from the Late Triassic, as well as the earliest equatorial record for anurans. These small fossils consist of complete and partial ilia with anteriorly directed, elongate, and hollow iliac blades, unmistakable anuran characteristics. These ilia are more similar to those of crown anurans than to those of their Early Triassic relatives Triadobatrachus from Madagascar and Czatkobatrachus from Poland, both of which are high latitude records. This series of new anuran fossils demonstrate that anurans were present in the Late Triassic in the equatorial region of Pangea. Furthermore, the presence of anurans in the Early Jurassic in the same stratigraphic sequence (Prosalirus bitis from the Kayenta Formation of Arizona) suggests that anurans survived the climatic aridification of this region in the early Mesozoic. This regional anuran survival of the end-Triassic extinction event could have been the result of recolonization or clade turnover. These new fossils highlight the importance of targeted collection of microfossils and provide further evidence for the presence of crown-group representatives of modern orders of terrestrial vertebrates prior to the end-Triassic extinction.