Aurorazhdarcho – a Jurassic azhdarchoid

Just a short post on this little fellow. I don’t generally like blogging on new taxa as a lot of other people cover them and there’s generally not much that can be said from an outside perspective that’s not in the paper. I don’t have much to add in that respect here either, but this is a nice thing for me to see out as I’ve seen the specimen knocking around in Dino Frey’s office on a number of occasions over the last few years while being assured it would be described ‘soon’. Well, now it is out and Aurorazhdarcho is born.

The specimen is obviously in superb condition (photos above and below lifted from Frey et al., 2011) though the head and neck are gone. Still, an impression remains on the sediment to show where they originally lay and given an idea of their original size and shape which is rather nice.

The most interesting thing though is the identification of this as member of the azhdarchoids. This most derived of pterosaur clades are otherwise known only from the Cretaceous, though a Jurassic origin is to be expected if (and for some, this is a big if) you accept that Germanodactylus is a dsungariptid and that this clade is the sister-taxon to the azhdarchoids. Certainly it has a few features that are unique to the group (that huge hindlimb for starters) and this identification looks good to me (though I have to confess I have yet to read the paper in full detail), though as ever with a specimen like this, the lack of a head is a real shame.

Frey, E., Meyer, C.A. & Tischlinger, H. 2011. The oldest azhdarchoid pterosaur from the Late Jurassic Solnhofen Limestone (Early Tithonian) of Southern Germany. Swiss Journal of Geosciences in press.

6 Responses to “Aurorazhdarcho – a Jurassic azhdarchoid”

  1. 1 Robert A. Sloan 02/11/2011 at 10:31 am

    Thanks for another great article! Those hind limbs are very long, I wonder if it ran and sprang into the air or if it was something like a wading bird in its behavior. I see the frustration about the head being gone, it would help a lot to see more of how this animal lived.

  2. 2 Mark Witton 03/11/2011 at 8:49 pm

    “The most interesting thing though is the identification of this as member of the azhdarchoids”

    Not sure I agree with this: the shape of the sternum, trunk length, pes/manus digit proportions, absence of a pnuematic foramen on the ventral side of the proximal humerus aren’t very azhdarchoid-like features. They’re very consistent with a ctenochasmatoid identification, though, and given that the specimen stems from Solnhofen – otherwise known as Ctenochasmatoid City (well, not really, but you see my point) – this identification seems much more parsimonious. Note that long limbs, pteroids about 70 per cent of the ulna length and short feet are also known in ctenochasmatoids via Cycnorhamphus. I don’t think you see splayed feet like that in azhdarchoids, either, but I could be wrong.

    • 3 David Hone 04/11/2011 at 10:28 am

      “Not sure I agree with this: the shape of the sternum, trunk length, pes/manus digit proportions, absence of a pnuematic foramen on the ventral side of the proximal humerus aren’t very azhdarchoid-like features.”

      Well I was hedging my bets Mark becuase I still haven’t read the paper fully, let alone ticking off all the anatomy with various ch lists. 😉

      I would say though that I’m not entirely sure I buy the ‘ Solnhofen = Ctenochasmatid’ issue. After all, there are lots of things that should be around in the Late Jurassic we’ve not found yet (incluidn, arguably, members of every pterodactyloid lineage) and of course at this point they would be rather less specialised and rare, so it wouldn’t be a major surprise if they didn’t have every derived characteristic going / looked more like basal forms and took us a long time to recover. Nothing like as major as issue as the actual anatomical ch’s you flag up, but worth remembering.

      • 4 Mark Witton 04/11/2011 at 11:04 am

        Very true: there should be an early azhdarchoid knocking around the late Jurassic somewhere, and I agree that a Solnhofen pterodactyloid specimen doesn’t equate to a ctenochasmatoid (there are, of course, probably dsungaripteroids in there, too). I just don’t think that Frey et al. exclude the possibility of Aurorazhdarcho being a ctenochasmatoid very successfully at all (indeed, their discussion of the affinities of this animal is very minimal, prefering to discuss functionality of its anatomy) and, conversely, do not provide overwhelming evidence for the animal being an early azhdarchoid, either. The crux of their argument, the idea that ‘lower deckers = azhdarchoids’ is especially dodgy: Frey et al. have yet to prove their case with articulated azhdarchoid specimens. Their argument seems to assume that long scapulae = low glenoids, but numerous perfectly articulated specimens of ctenochasmatoids show this is not the case: their long scapulae simply lie along the dorsal surface of the ribs in a rather normal fashion. We also have good shoulder girdles for thalassodromids and azhdarchids that conclusively refute the ‘lower decker’ construction in these azhdarchoids. As such, I’m not saying the ‘lower decker’ idea is incorrect, just that the case as it’s currently presented has not, to my eyes, been demonstrated beyond all doubt.

  3. 5 Mickey Mortimer 05/11/2011 at 3:08 am

    Ha. I’ll be highly amused if this turns out not to be an azhdarchoid, since I found the paper’s phylogenetic perspective to be …. highly problematic ( see ). I’d trust Witton’s thoughts over the paper’s musings any day, but would love to see it included in a cladistic analysis.

    • 6 David Hone 05/11/2011 at 8:47 am

      Well I did read the commentary on cladistics and yeah, don’t agree. I’ve had many arguments with Dino over the years on this and well, he’s entitled to his opinions, but obviously we don’t agree. Such is research.

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