Tuesday, December 04, 2007

Moloch 'n' Phrynosoma: Freaky spiny lizards!

When I think of prehistoric animals, I'm always fascinated by how much more "exotic" they look in comparison to modern fauna. Dinosaurs look infinately cooler than mammals, for instance, what with their horns, spikes, frills, plates, and armor. Birds, I'll admit, look much more baddass today than they did in the Mesozoic, although some Cenozoic birds were pretty awesome--Teratornis, Diatryma, and South American terror birds? I'll take those any day over albatrosses and emus. But there are two modern lizards who look absolutely prehistoric, and I love them both. I doubt they'd make good pets, but dammit if I wouldn't try if given the chance. Moloch horridus, from Australia, and the various species of Phrynosoma, from the American southwest, are among my very favorite modern animals.

You lookin' at me, punk?

Phrynosoma is better known as the horny toad. Aside from being the reptilian equivalent of a porcupine, Phrynosoma is famous for its ability to burst its own capilaries and shoot an impressive stream of blood from the corners of its eyes. This is not only a shocking display, but the blood apparently tastes quite bad to mammalian predators. Birds don't seem to mind the red stuff, though, and when attacked by one of its larger dinosaurian cousins, the horny toad will thrash its head around, attempting to injure its attacker with its impressive cranial horns. Thankfully, horny toads are quite small, and will often fit comfortably in the palm of one's hand. Given their ridiculously fat bodies and short little legs, horny toads are not terribly difficult to capture, although its body spines (which are merely modified scales) can be quite prickly, especially in older individuals.

Look at me! I'm scary!

Moloch horridus is, perhaps, the most decorated lizard on the planet, or at the very least, in Australia. Despite its fearsome appearance, Moloch is actually quite small, slow-moving, and docile. When confronted with predators, M. horridus is more often than not tuck its head down and prey that its attacker bites off the enlarged "false head" spine that erupts from the back of its neck. Moloch runs with a jerky, robotic gait, and will often stop mid-stride, with one or two feet off the ground. The "thorny devil" is a specialized ant eater, and will eat several thousand in one sitting. As eating ants nonestop requires a lot of time, the devil has special hydroscopic grooves in its skin and between its spines which guide water directly to its mouth. The lizards "gulp air" to move the water toward the gaping maw. Despite its namesake, though, Moloch horridus does not have a thorny skeleton. It's spines are entirely external.

Phrynosoma (top) vs. Moloch (bottom)

The CAT-scan image above, taken from here, illustrates this oddity. Moloch has some textured bone where its giant cranial spines originate, but there is no underlying bony structure to its horns. In stark contrast, Phrynosoma's cranial horns all have bony cores. In fact, its skull is just as spikey as a pachycephalosaur! I was surprised to see a lack of bony horn cores on Moloch, and there are implications here for paleoart. If large, impressive spines and growths don't always have bony cores, then just imagine how wrong we could be about some prehistoric animals. Paleontologists are always musing on how duckbill dinosaurs protected themselves from predators. Odor? Herding? Tail whacking? What if they had huge external, epidermal spines? That would disuade predation! Even Phrynosoma, whose head is the only part of the body with bony horn cores, has largish epidermal spines all over its body. The function of these structures is obviously for protection (there is no marked sexual dimorphism between males and females of these lizards).

It's also interesting that Phrynosoma is, like Moloch, an ant-eater. It does not have the complex hydroscopic system that Moloch has, but one wonders whether ant-eating lends itself to a spikey body type, at least among lizards.

I bring these animals up today to prepare you readers for a bizarre creature I'll be restoring for Will at The Dragons Tales on Saturday. It's a creature you're probably at least aware of, but restored in a way that's not necessarily "normal." Also, Phrynosoma and Moloch are awesome!


Christopher Taylor said...

I posted a couple of pictures a while ago demonstrating the incredible lack of aggression thorny devils show. Also, I'll second that the way they move is completely undescribable if you haven't seen it - in my post, I compared it to stop-motion photography. They don't so much walk as progress through a series of tableaux.

Will Baird said...

Looking promising, Zach!

I used to catch horned toads when I was growing up in Los Alamos, NM (yes, yes, THAT Los Alamos). They were very kewl to catch and keep. There was even a particular time of the summer to go out and get the hordes of baby ones too. I NEVER got them to squirt blood at me though after several years of trying. I started to chalk the blood squirts up to being urban legends...then people online have pix, sooo...

I am looking forward to seeing your little thorny fiend for the post.

Logan said...

sweet i'd been trying to find the thorny devil's name ever seen seeing an unnamed picture of it in a book at chapters... also you might wanna look up the armadillo lizard... and with enough looking around i think all three can be found captive bred in the pet industry