an early dromaeosaur

Blogging on Peer-Reviewed Research I’ve always been interested in dinosaurs, & I loved Jurassic Park. Especially the raptors – they reminded me of birds in many ways. Which makes sense, of course, given that the majority consensus is that birds evolved from maniraptor dinosaurs 🙂 Anyway, all this means that dino headlines are always going to make me look twice. As I did at an item in today’s Royal Society news feed: the earliest known dromaeosaur from South America.

Both birds & dromaeosaurs are classified as ‘maniraptors’, a name that reflects the hand-like structure of their front ‘feet’. (They both have very similar wrist structures as well, which in birds allow the wing – ie hand & arm – to fold in close to the body when not being used to fly. The assumption is that maniraptor dinosaurs could do this as well.) Dromaeosaurs (eg Deinonychus **) are exemplified by the raptors of Jurassic Park, with their fearsome sickle-clawed back feet. Remember Sam Neill’s character scaring a kid on his field excavations, telling him how a raptor could eviscerate its prey with that claw?)

** Sorry – the text’s in French but I’ve linked to that site because its images are so delightful!)

Up until now, most maniraptor fossils have come from Jurassic & Cretaceous rocks in the northern hemisphere. However, some of those Cretaceous fossils are quite diverse, especially those from China. This, together with the fact that the bird-like Archaeopteryx dates from late Jurassic sediments, suggests that maniraptors have probably been around for quite a lot longer – perhaps even to the time when we had the super-continent Pangaea. The report by Peter Makovicky & his co-workers (2008) of a South American raptor bears this out – maniraptor dinosaurs once wandered round South America 🙂 Which suggests that they might also have roamed the other Gondwanan lands: Africa, India, Australia & Antarctica. (There are some fragmentary fossils from these regions that have been described as dromaeosaurids, but apparently there’s some disagreement about whether that’s what they really are.) And it also suggests that raptors have been around a lot longer than we originally thought.

(We had a our own dinosaur fauna in New Zealand. Most of the discoveries in this area are due to the work of Joan Wiffen, who with her husband Pont hunted for their remains in the Waikaremoana area. I remember first meeting her when I was about 15, at a time when most experts agreed that dinosaurs had never made it to NZ. Joan wasn’t deterred by this, & went on to make a significant contribution to our knowledge of NZ’s dinosaurian past. I’m going to finish off with a wonderful quote from the Te Papa web page:  

Joan Wiffen is a remarkable model for women in science – tenacious, courageous, and adaptable… [She] is also a model for us all as learners – taking on new challenges in her middle years, not being put off by scarcity of resources, and pursuing her interests wholeheartedly.

P.J. Makovicky, S. Apestegula, & F.L. Agnolin (2008) The earliest dromaeosaurid theropod from South America. Nature 437: 1007-1011  

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