May 21, 2008

Frogamander: A Putative Member in the Common Ancestral Line of Frogs and Salamanders

A few years ago, paleontologists using evolutionary theory to predict its location in rock strata found the 375 million year old Tiktaalik rosae, a member of the ancestral line that links fish with tetrapods, particularly with amphibians. That was just two years ago, in 2006.

Today comes word of a somewhat later common ancestor in the tetrapod line. This one is a likely relative, if not the precise species, that gave rise to modern frogs and salamanders. The little critter, just a couple of inches long, lived 290 million years ago and has traits in common with both modern frogs and salamanders. It has been dubbed Gerobatrachus hottoni and lived in a swampy area that today forms part of the state of Texas.

Scientists discover "frogamander" fossil

The discovery of a "frogamander," a 290 million-year-old fossil that links modern frogs and salamanders, may resolve a longstanding debate about amphibian ancestry, Canadian scientists said on Wednesday.

Missing Link/Transitional Fossil Between Frogs and SalamandersModern amphibians -- frogs, salamanders and earthworm-like caecilians -- have been a bit slippery about divulging their evolutionary ancestry. Gaps in the fossil record showing the transformation of one form into another have led to a lot of scientific debate.

The fossil Gerobatrachus hottoni or elderly frog, described in the journal Nature, may help set the record straight.

"It's a missing link that falls right between where the fossil record of the extinct form and the fossil record for the modern form begins," said Jason Anderson of the University of Calgary, who led the study.

"It's a perfect little frogamander," he said.

Gerobatrachus has a mixture of frog and salamander features, with fused ankle bones as seen only in salamanders, a wide, frog-like skull, and a backbone that resembles a mix of the two...

"The fossil itself is almost perfectly complete," Anderson said.

"It died on its back. Its legs and arms were curled up on its belly and it's that part that weathered away..."
Granted, this isn't the crocoduck that Kirk Cameron demands as proof of evolution, but hey, it's a frogamander, and that ain't too shabby.

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