Um, dude, there’s a thing on your neck

March 15, 2010

On the off chance that the postparapophyses of Shunosaurus weren’t enough to sate your appetite for Sino-pod rib-related weirdness, here are a couple of fused cervicals of Klamelisaurus, from the Middle Jurassic of China (from Zhao 1993:plate 1). These are weird for a couple of reasons. First, although fused caudals are pretty common in sauropods (see here), and fused dorsals turn up a lot (see discussion here), and the fusion of the atlas to the axis is not unheard of (see here and here), fusion of the middle or posterior cervicals is rare. Which makes intuitive sense–presumably fusing up your food-reaching organ is counterproductive. The only other example I know of is the pair of fused posterior cervicals in the AMNH 5761  Camarasaurus supremus (which, oddly enough, I don’t think we’ve covered yet on SV-POW!). If you know of others, please let me know.

Anyway, what’s really weird about the Klamelisaurus verts is not the fusion but the bar of bone connecting the cervical rib of the first vertebra back to one or more of the centra. I think that the weird pseudo-parapophysis-thingy is not the parapophysis of the second vert, which is hanging down just behind, but some kind of extra ossification off the postero-ventro-lateral corner of the first vert’s centrum. Admittedly, that’s a lot of interpretation to hang on one grainy photo of a specimen I’ve never seen. But I’ve seen something similar in some bird cervicals, where there is sometimes  a prong or hook of bone from that corner of the centrum sweeping down and out to brace against the longus colli ventralis tendon that comes  off the cervical rib. One of the Apatosaurus cervicals on the wall at Dinosaur National Monument has a similar pair of hooks on its posterior centrum. Irritatingly, I don’t have any digitized photos of the Apato vert, and I can’t find any photos at all that show what I’m talking about in birds. Sorry to tantalize, I learned it from Darren. When I get pix, I’ll post ‘em.

In the meantime, you can amuse yourself by pondering the strangeness of the fused Klamelisaurus verts, and by watching the Dinosaur National Monument Quarry Visitor Center get demolished here.

Reference
Zhao X. 1993. A new mid-Jurassic sauropod (Klamelisaurus gobiensis gen. et sp. nov.) from Xinjiang, China. Vertebrata PalAsiatica 31(2):132-138.

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One Response to “Um, dude, there’s a thing on your neck”

  1. Nima Says:

    WOW. That thing is just weird. And it’s the first I’ve ever seen of Klamelisaurus. I can understand how Apatosaurus could grow weird processes like that too. It’s got some very extreme-shaped cervicals.

    Was Klamelisaurus a close relative of the brachiosaurids? I’ve read that it was a basal sister group or something of the sort, yet everything I’ve seen of Bellusaurus (which may just be a Klamelisaurus) looks more like an undifferentiated basal sauropod, with some vague Shunosaurus- or Datousaurus-like design elements.


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