Gerobatrachus - Discovery

Discovery

The type species, Gerobatrachus hottoni ("Hotton's ancient frog") was described for the first time on May 22, 2008 in the journal Nature. The "frogmander" fossil, as journalists swiftly dubbed it, was collected in the mid-1990s, then rediscovered in the collections of the National Museum of Natural History, Washington DC, in 2004.

Comparative biologist Jason Anderson of the University of Calgary led the new analysis of the fossil, claiming he recognized the "froggy salamander-y sort of look" of the fossil. Anderson judges that the animal would have looked like a stubby-tailed salamander with froglike ears and that it "pretty convincingly settles the question frog and salamander shared origins from the same fossil group."

The analysis is not yet complete, though. National Geographic News reported that the Field Museum’s John Bolt, a curator for fossil amphibians and reptiles, cautioned that it is difficult to say for sure whether this creature was itself a common ancestor of the two modern groups, given that there is only one known specimen of Gerobatrachus, and an incomplete one at that. "At this point I would say it is by no means certain that this is representative of a common ancestor to frogs and salamanders, although it might be," Bolt said. Bolt also says, "The most astonishing thing to me about this study is that this animal is far more froglike than I would ever have expected from its age. Nothing this nonprimitive has ever been described from this age. It's just amazing."

David Marjanović and Michel Laurin (2008, 2009) doubted that Gerobatrachus was indeed a close relative of frogs and salamanders and that lissamphibians are polyphyletic as recovered by the authors of the description of Gerobatrachus. The phylogenetic analyses they conducted (Marjanović and Laurin 2008, 2009) confirmed that G. hottoni was an amphibamid temnospondyl, but simultaneously found lissamphibians to be monophyletic and descended from lepospondyls.