batrachia

atleast5lizards  asked:

Hi Mark! I have a question about dendrobates tinctorius and I have yet to find the answer on my own. My university has several dyeing dart frogs on display, and I've noticed that especially when they are poised to hop, sometimes they will rapidly wiggle their middle toe on their back legs for a few moments. None of my professors seemed to know what that behavior might be linked to. Do you have any ideas?

I HAVE NOTICED THIS TOO. Actually I noticed it in some rather large toads of a species I cannot now recall. But they were constantly wiggling their toes. Then I started paying attention, and lo and behold, there are tooonnes of frogs that do it. I have no explanation for this, but I am glad I am not the only one noticing it! I thought maybe it is subtle signalling… but it could also be just a weird neural misfire. But it would be strange for one to be so consistent across the batrachia. So I have no idea.

Amphibian August #29 – Kokartus & Czatkobatrachus

Heading into the end of the month, it’s finally time for some lissamphibians! This group contains all living amphibans – frogs, salamanders, and caecilians – and we’re going to look at some of their first known representatives.

While these animals’ fossil records only definitively go back to the Early Triassic, molecular studies suggest they actually split off from their ancestors (whoever they were) some time earlier, during the Permian.

Salamanders

One of the earliest salamanders was Kokartus from the Middle Jurassic of Kyrgyzstan (~167-164 mya). About 20cm long (8″), it was fairly robust and would have superficially resembled living mole salamanders, probably leading a similar terrestrial burrowing lifestyle – although it lacked some of the bony and muscular anatomical features of its modern relatives.

Another Kyrgyz fossil amphibian named Triassurus may represent an even earlier larval salamander from the Late Triassic (~242-221 mya), but the one known specimen is so poorly preserved that it can’t be confidently classified.

Frogs

Czatkobatrachus is known from the Early Triassic of Poland (~251-247 mya). Along with Triadobatrachus from Madagascar, it was one of the earliest known “proto-frogs”, showing transitional features between their more salamander-like ancestors and the later true frogs. Only about 5cm long (2″), its relatively long limbs and well-developed skeleton suggest it was an agile terrestrial animal, possibly even capable of some degree of primitive frog-like hopping.