Reptilian Rants

According to news from CNN.com, (though technically, AP), mammals weren’t itching to take over the newly vacated niches left behind by the dinosaurs 65 mya.

A new phylogenetic study of mammals, reported that there was no burst of activity following the demise of the dinosaurs. There was some flurry of speciation in animals that left no descendants, but all extant mammals remained pretty low key until around 55-35 mya.

As is typical for these studies, the results are somewhat controversial. Some folks are questioning the dating methods used, while others are both shocked and impressed with the results.

Though the AP sticks in the hyperbolic: “…challenges a long-standing theory.” statement, I doubt we’ll be seeing textbooks getting rewritten anytime soon.

~Jura

Apparently these past couple of days have been a bit of a boon to paleontology. 3 new finds have just been announced.

The most recent find, is that of a new species of gliding reptile from the early Cretaceous period (125 mya).

See: New Scientist for a full description.

The neat thing about this critter is that it is the oldest gliding lizard to date. Back in the Permian and Triassic periods, there were various gliding critters like Sharovipteryx, Coelurosauravus, and Kuehneosaurus. None of these reptiles were lizards, though.

This new guy, Xianglong zhaoi, is the first true member of squamata that glided. The New Scientist illustration makes the critter look nearly exactly like a modern day Draco. I haven’t read the paper yet, so I’m not sure how accurate it is. Finally, another neat thing about this little guy (only 15 cm long) is that it was preserved so well that one can actually make out the wing membrane itself. Very cool stuff.

The second bit of news is among the crocodyliformes. A new species of Metriorhynchid suchian has been unearthed in Eastern Oregon. Metriorhynchids were a completely marine group of crocodyliformes. They are easily diagnosed by their thin snouts with needle like teeth, their lack of any real scalation (in specimens that retain skin impressions) and the presence of a bifurcated, or forked tail. Imagine something like the horrible love child of a crocodile and a shark.

Full story here

According to the report, this new guy, who has yet to be named, lived around the middle to late Jurassic (180-150 mya). According to the report, this species retained short stubby limbs (all other Metriorhynchids evolved paddles), which suggests that it might have still made forays onto land. It was probably a coastal dweller. It must have been pretty clumsy on land, though, given its large forked tail.

The last bit of news is in the realm of dinosaurs. Paleontologists have recently announced the discovery of an ornithischian dinosaur that was a burrower. The new dino, named: Oryctodromeus cubicularis, was found inside an ancient burrow. It also showed a couple of unique features that suggest this animal did the burrowing itself.

One can read more on the story here.

The paper will appear in the next issue of: Proceedings of the Royal Society B.

Once I get ahold of these papers, I may make an update.

Stay tuned.

~Jura

A little over 30 years from when it was originally put on the endangered species list, the American crocodile (Crocodylus acutus), has been officially moved from “endangered” to “threatened.”

Though the animal remains endangered in South America, in the states things seem rosier.
In Florida the animals have gone from a scant 300 wild animals, to 2,000. Though this pales in comparison to the amazing comback that the American alligator (Alligator mississippiensis) made (over 1 million individuals live in the Southern U.S.), it is still an impressive bounceback.

Kudos to the American croc and the conservationists who worked tirelessly to bring it back from the brink.

Once again, I’m coming late to the party on this one. It seems that fisherman in Antarctica’s Ross Sea caught the largest specimen of Colossal squid (Mesonychoteuthis hamiltoni) to date.Most folks are aware of Architeuthis dux, the giant squid.Few folks are aware of the fact that while A.dux is the longest, it’s actually M.hamiltoni that is the largest. Judging from sucker marks found on sperm whales, as well as actual remnants found in sperm whale stomachs, these guys appear to be much nastier than your garden variety giant squid.

It’s too bad that this one was found dead already. Hopefully we’ll be able to nab some footage of these living giants, one day. Till then, we’ll have to make due with dredging up remnants of these awesome beasts.

~Jura