Off-topic: Get down, get fuzzy, Tianyulong!
March 19, 2009
That clanking sound you just heard was pretty much the entire field of paleontology evolutionary biology wired humanity dropping a solid gold brick: Tianyulong, a basal ornithischian from (where else?) China, has been found with dino-fuzz (Zheng et al. 2009). Not exactly protofeathers, but pretty darn similar. And if they’re in theropods and ornithischians, they were probably primitive for Dinosauria (at least; comparisons of these integumentary structures to pterosaur ‘hair’ are probably coming). It’s certainly possible that the common ancestor of Ornithodira (the pterosaurs+dinosaurs clade, which encompasses most non-croc-line archosaurs) was fuzzy.
(So much for the “fact” that we “know” that small dinosaurs couldn’t have been endotherms because of their naked skin–see, e.g., pretty much everything ever written by Feduccia, Ruben, and the rest of the BANDits [Birds Are Not Dinosaurs cultists]).
It’s true that we have skin impressions from many dinosaurs that show scaly skin, so if dino-fuzz was primitive for dinosaurs it must have been lost, or had a restricted distribution on the body (like a midline crest), or been ontogenetically transient (possibly present only in babies) in many taxa. If there were any shaggy sauropod skin impressions out there, we’d really, RE-hee-huh-HEEELLY like to know. So far, zip. Even the skin impressions from the Argentinian sauropod embryos show bare, scaly skin (Chiappe et al. 1998).
Still, those skin patches don’t cover the entire embryo. We can’t rule out some fuzz even in the Argentinian embryos, and except for a scrap of bone shard of excellence here and there (Britt and Naylor 1994), sauropod embryos and their skin are otherwise ridiculously unknown to our planet. So we can dream, for a while longer anyway. Back in 1994, Greg Paul drew a hatchling sauropod with dino-fuzz (Paul 1994:fig. 15.3, above), and we’re bringing it back in honor of Tianyulong.
Here’s your obligatory sauropod vert shot for this post. Tremble as the ancient, bloated hulk looms out of the mists of deathless time, like an ageworn stone idol or some eldritch Lovecraftian horror!
Oh, and behind Mike you can just make out the AMNH Brontosaurus (yeah, we know, we’d like to bring that back, too).
UPDATE: MARCH 19
James O’Donoghue wrote a piece for New Scientist on sauropod gigantism, which you can read for free here. He kindly cited my work on air sacs, and even more kindly threw in a link to an SV-POW! post, which I’ll let you find for yourself. Now that I’m sending you there, the hyperlink circle is complete.
Two great things came in the mail yesterday, but those will be subjects of future posts. Stay tuned, true believers!
- Britt, B.B., and Naylor, B.G. 1994. An embryonic Camarasaurus (Dinosauria, Sauropoda) from the Upper Jurassic Morrison Formation (Dry Mesa Quarry, Colorado); pp. 256-264 in Carpenter, K., Hirsch K.F., and Horner, J.R. (eds), Dinosaur Eggs and Babies. Cambridge University Press, Cambridge.
- Chiappe, L. M., Coria, R. A., Dingus, L., Jackson, F., Chinsamy, A., and Fox, M. 1998. Sauropod dinosaur embryos from the Late Cretaceous of Patagonia. Nature 396: 258–261.
- Paul, G.S. 1994. Dinosaur reproduction in the fast lane: implications for size, success, and extinction; pp. 244-255 in Carpenter, K., Hirsch K.F., and Horner, J.R. (eds), Dinosaur Eggs and Babies. Cambridge University Press, Cambridge.
- Zheng, X.-T., You, H.-L., Xu, X., and Dong, Z.-M. 2009. An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures. Nature 458:333-336.