Gerobatrachus hottoni
- Gerobatrachus hottoni
Painting by Michael Skrepnick,
from the press release at EurekAlert.
- New Amphibian: Gerobatrachus hottoni
- Name means:Hotton’s Elder Frog
- Relations: Amphibamid temnospondyl and stem-batrachian (an early offshoot on the lineage leading to frogs and salamanders)
- Location: Texas, U.S.A.
- Age: Early Permian, ~290,000,000 years ago
- Size: Less than 12cm (5 inches) long
- Info: The three groups of living amphibians (frogs, salamanders, and caecilians) most certainly had their roots in the great amphibian radiations of the Late Paleozoic Era, but the fossil record has provided few clues that help pinpoint their precise ancestry. Gerobatrachus was a small temnospondyl, part of a very successful and numerous group of amphibians in the latter part of the Paleozoic. The remains of Gerobatrachus exhibit a unique mosaic of features in its teeth, ears, limbs, and vertebrae that suggest it may have been close to the origins of both modern frogs and salamanders. Although many researchers have proposed a close relationship between all three groups of living amphibians, a phylogenetic analysis that included Gerobatrachus found that caecilians had their origins in a completely different group of Paleozoic amphibians, the lepospondyls.
- Reference: Anderson, J. S., Reisz, R. R., Scott, D., Fröbisch, N. B., and Sumida, S. S. 2008. A stem batrachian from the Early Permian of Texas and the origin of frogs and salamanders. Nature 453, 515–518 (22 May 2008) | doi:10.1038/nature06865. The article is available for download from the Center for North American Herpetology PDF Library.
- Web coverage:
—Matt Celeskey.
File under: Permian, Recent Discoveries, Tetrapods.
So…as opposed to vanishing before the Mesozoic, lepospondyls survive to today?! That would be something.
Does anyone know much about how the LTr/EJ Eocaecilia (which I believe has two sets of tiny limbs) matches up with this? Are the caecilians supposed to be close to the limbless aistopods, or are their features believed to be convergent?
Evolution is made up of so many “suggest it may have been” statements how can we contiue to call it science?
Hi Adam -
From the paper, “…the oldest known caecilian Eocaecilia falls within recumbirostrine lepospondyls, sister group to Rhynchonokos and, one step further out, the brachystelechids.” I’m afraid that’s all the insight I can muster, as my familiarity with lepospondyl classification is basically zilch. If any readers have a better answer, please chime in!
Hi John -
Well, first of all I should state that “suggest it may have been” is my own phrasing, and different reports (and possibly the researchers themselves) might very well use more confident language.
Of course, since it is science, the door is always open for a new fossil, or a new set of eyes looking at this fossil, that leads to a different conclusion. On the flip side, new fossils and new sets of eyes might well confirm the phylogeny presented by Anderson et al. There’s even a pretty good chance that some parts of the research described here will be bolstered by future work, while other parts will require modification when faced with new insights and discoveries.
The lack of certainty can be frustrating, but I happen to think it’s more fun to watch the stories unfold than to find satisfaction with any particular answer.