Monday, March 16, 2009

Proactive dicynodonts

Remember this guy? It's Odobenodon bairdi, a thought experiment designed to deduce what some Permian critters would have evolved into had the Permio-Triassic extinction not occurred. It's a project I'm working on with Will Baid of The Dragon's Tales. Anyway, this was my first pass at the "walrodont," as we're calling it, and it looks bad now. I'm continually reworking the animal's gross morphology. Skull doesn't make sense, limbs are too long, etc. But I do like the idea of a walrodont, though the more I think about it the less it makes sense.

Anyway, two new critters have popped up. Transitional forms between a walrodont and your average dog-sized dicynodont. First is the "hippodont," an animal not that different from your garden-variety Placerias, but bulkier. We haven't decided on a formal name yet, but I like him!

Forelimbs sprawl, hindlimbs are held erect. All I know about dicynodonts, I learned from Will Baird. They're very strange critters, totally unlike anything that's come before or since. The next up is the "desmodont," sort of a cross between a dicynodont and a desmostylan. I figured that the first tentative steps into a marine environment would be more like paddles, and desmostylans have been compared to paddling bears before (I don't have the citation right in front of me), so they seemed like a good model.

No formal name here, either. I can definately see this creature evolving into the walrodont at the top of the post, although the walrodont needs some major changes. In fact, I've since come up with a new walrodont, but I had it almost as much. Here it is for comparison's sake:

Oh, geezus, look away! The hindlimbs are all wrong, and the forelimbs are too...bulky! I'm starting to think that dicynodonts would go the way of sirenians--eliminate the hindlimbs entirely, but that makes landlubbing something of a problem. So the walrodont is tough for me. But like I said, dicynodonts are new to me. If anyone has helpful PDF's, especially any detailing their cranial anatomy or general skeletal build, that would be enormously helpful. Anyway, these are the "new" dicynodonts. What'cha'll think?


Andy said...

Love 'em!

Will Baird said...

They really are great, Zach. The sirenodont that you sent me even fits in here. The walrodont does look good. After your criticism, the back legs could be modified, but not much. I really like the terrestrial stance. Really-really. I'd change the beaks a bit in the previous ones, bu that's it.

Glendon Mellow said...

They look marvelous, Zach!

Wow. Just when you think nature can't generate anything new and surprising. I like how you've done the swimming one in particular, it has great posture. Not in a hurry, just going somewhere.

Will Baird said...

ok. definitely close the beaks. I don't remember seeing anything about a gap. These are dicyns, not rhyncosaurs!

Metalraptor said...

Your aquatic dicynodonts look really exciting, I cannot wait to see more of your project. I once tried to do a world with no Permian extinction, but it failed because I know nothing about synapsids and other Permian animals (I was dumb and young enough to have sphenacodontids surviving into the Late Permian, how dumb was I?)

But anyway, cannot wait to see more of your project. Is it going to be a big, convoluted one like Spec, or will it just be limited to some blog posts? Either way, good work.

I like the idea of aquatic dicynodonts. Ironically, the middle picture in the transition between the three looks more like a desmostylian than your desmodont. In fact, I recall seeing a desmostylian that looked a lot like that in exactly that pose. Then again, Behemotops from the Oligocene of the Pacific Coast was a bit more elephantine, more like your upper picture.

One question though, is the walrodont completely herbivorous, like a big tusked manatee, or have these animals secondarily developed carnivory or durophagy?

Zach said...

Seaweed, kelp, maybe tufts of algae. Dicynodonts are restricted to what their beaks can snip off. I'm glad you like the project. We're certainly excited about it!

Metalraptor said...

Herbivore sounds good. Anyway, I was wondering durophagy because the walrodont could always use its tusks for stirring up clams from the muck, and then use their beaks to crush them. But then again, dicynodonts are herbivores. I just suggested it might be durophagous because of the lifestyle of the modern animal it seems to be convergent on to an extent; the walrus.

What will the main terrestrial predators be in "Permian Planet"? I was looking at some writings on the Permian fauna of the Karoo basin, and the subsequent Triassic survivors, and I caught myself wondering if the ictidosaurs like Thrinaxodon would have taken over from the gorgonopsids if given enough time.

But what are your dominant predators? More gorgons? Therocephalians? Or did you do that thing I saw one person do, and have an archosaur radiation in the Cenozoic, after the K-T event hits. Anyway, keep me posted.

Stanton said...

These make me think of the desmostylians