Frog legs with… claws?

Scientists have discovered that some African frogs have claws that burst through the skin of their toes much like those of Wolverine in X-Men. These frogs are the only vertebrates known to brandish claws in such a self-wounding manner. What's also surprising is that these claws are made of bone, rather than the hard protein called keratin that normally comprises fingernails, claws and hooves. Lead study author David Blackburn, a biologist from Harvard University, reports in Biology Letters that he had noticed that the flailing, kicking frogs left scratches on their antagonists' arms. He and other researchers then combed through museum frog specimens and discovered the bone-claws. Other scientists had mentioned their existence over the past century, but this is the first time it was confirmed. It appears, though, that Cameroon tribesmen were long aware of these amphibians' fierce secret weapon; they typically use long, nail-studded poles or machetes to lay blows to the frogs' heads when hunting to avoid getting slashed.

7 Comments

1. 1. Carl Zimmer 09:32 PM 5/30/08

   Pterosaurs were not dinosaurs. They were a separate lineage of reptiles. Flying dinosaurs are called birds.

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2. 2. Hugh Jones 06:02 PM 5/31/08

   There seems to be some ambiguity in the word dinosaur. Pterosaurs had long thin bones like birds, but unlike birds didn't have the anatomy for sustained flight. Sauropods, a distant relative of the Ptreosaurs in the Cretaceous period are now generally recognized as the ancestors of modern day birds. Snakes, alligators and lizards are reptiles, but I think Ptersaurs deserve a better definition. The study of paleontology would be better served if they could somehow drop the antiquated term "dinosaur", and come up with a more definitive description.
   
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   Edited by Hugh Jones at 05/31/2008 11:46 AM

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3. 3. onleyone 04:39 AM 6/2/08

   Hugh--
   
   I'm afraid the ambiguity here is not where you claim.
   
   > There seems to be some ambiguity in the word
   > dinosaur. Pterosaurs had long thin bones like
   > birds, but unlike birds didn't have the anatomy for
   > sustained flight. Sauropods, a distant relative of
   
   I think if you do the research you'll find that pterosaur anatomy is at least as exquisitely adapted for flight as modern birds. (Try a Google search for "birds", "flocculus", and "pterosaur".)
   
   > sustained flight. Sauropods, a distant relative of
   > the Ptreosaurs in the Cretaceous period are now
   > generally recognized as the ancestors of modern day
   > birds. Snakes, alligators and lizards are reptiles,
   
   Being direct descendants of (probably Jurassic) theropods (of the Saurischian lineage, which includes sauropods and prosauropods, but not Ornisthischian stegosaurs or "duckbill" dinos), birds are much closer relatives of dinosaurs than are pterosaurs (which are of a separate archosaurian line altogether), as Mr. Zimmer succinctly commented earlier.
   
   > birds. Snakes, alligators and lizards are reptiles,
   > but I think Ptersaurs deserve a better definition.
   
   Taken altogether, I don't see the ambiguity; if crocodilians (also of the Archosauria) and their extinct kin are "reptiles", then so too are pterosaurs. I'm fairly certain most paleontologists would agree.

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4. 4. Hugh Jones 06:41 PM 6/2/08

   onleyone, I enjoyed your feedback. Of course my observations that there exists some ambiguity in the word dinosaur were merely subjective, and only voiced in hopes that there might someday be a more appropriate term. Although I'm intensely interested in the subject, I certainly wouldn't pass myself off as any kind of expert in this field. That being said however, a couple of Nova programs and other books on the subject I have read point out that the Pterosaur type animals didn't have "wishbones" or otherwise developed breast muscles necessary for sustained flight. This fact seems consistent with the Azhdarchid article. This study is always evolving, as example; in Nova "Four Winged Dinosaur", the scientists couldn't agree on at what level of the evolutionary scale the specimen belonged because it's remains were so badly crushed. Although I clearly have my favorites among theories in this evolving study, I'm very interested in listening to different viewpoints.
   
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   Edited by Hugh Jones at 06/02/2008 11:46 AM
   
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   Edited by Hugh Jones at 06/02/2008 11:49 AM

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5. 5. isaacmeirn 11:58 PM 6/2/08

   Pterosaurs were dinosaurs?
   Hornbills and storks are their relatives today? Can this crap really be on SI's web site?

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6. 6. Hugh Jones 02:46 AM 6/3/08

   You obviously have the wrong website, the "SI" website is down the hall and to your right.

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7. 7. jacomus d'paganus-fatuus 08:32 PM 6/9/08

   Great concept, a knuckle-walking pterosaur (not a dinosaur but a flying lizard) on the direct evolutionary route leading to geckos and airline pilots.

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