Another flightless pterosaur: the anurognathid PIN 2585/4

This is one of those fossils
I had heard about a long time ago, but never saw until today. I read once, (not sure where, but perhaps in Bakhurina 1988?), that there was a second specimen of Batrachognathus on the holotype Sordes plate. Problem was, I could never see another pterosaur on the Sordes plate. That left a big question mark over my head. Now I know that the widely circulated images of Sordes deletes or separates the second pterosaur from Sordes on the original plate (Fig. 1).

Today,
I finally saw both pterosaurs on the same plate on an online image (Fig. 1). Apparently this is the only instance of two distinct genera of pterosaurs found on the same plate. Not sure how this image snuck out of Russia.

Figure 1. The holotype of Sordes, PIN 2585-3. includes a small anurognathid, PIN 2585-4.

Figure 1. The holotype of Sordes, PIN 2585-3. includes a small anurognathid, PIN 2585-4. 3 frames, 5 seconds each.

Not sure why this little anurognathid
has not gotten more attention. By the way, It does not nest with Batrachognathus in the large pterosaur tree. Perhaps it did back in 1988 when only a few anurognathids were known. But now we have many more anurognathids to compare it to. Sordes (Sharov 1971) has been known for over 45 years. That’s a long time to overlook/ignore/ a find like this. Apparently this is the specimen that was said to have bristles around the jaws (Bakhurina 1988) because it does and the holotype  (Rjabinin 1948) does not.

Figure 2. Tracing of the anurognathid PIN 2585-4 with soft tissue in gray. This, obviously, is a low-rez image. Even so, nearly all of the major bones preserved on the plate could be traced. The skull, in particular, matches sister taxa at reptileevolution.com, in contrast to the Bennett 2007 interpretation.

Figure 2. Tracing of the anurognathid PIN 2585-4 with soft tissue in gray. This, obviously, is a low-rez image. Even so, nearly all of the major bones preserved on the plate could be traced. The skull, in particular, matches sister taxa at reptileevolution.com, in contrast to the Bennett 2007 interpretation.

The PIN 2585-4 specimen has tiny wings
and large legs. Based on comparisons with other anurognathids, this specimen appears to be yet another flightless pterosaur. An unrelated flightless pre-azhdarchid, SOS 2428, was reported on here several years ago.

Figure 3. Click to enlarge. The PIN 2585/4 anurognathid reconstructed in two views. Note the small wings and large legs on this flightless pterosaur.

Figure 3. Click to enlarge. The PIN 2585/4 anurognathid reconstructed in two views. Note the small wings and large legs on this flightless pterosaur, the second one now known. Finger four retains 5 elements including a tiny ungual.

An obligate biped
with strong hind limbs and extremely long tibiae, the PIN 2585/4 specimen would have been a better bipedal runner and, based on comparisons to volant pterosaurs, probably could not fly with such gracile, small wings. It would also have a tough time walking as a quadruped, so was obligated to walk as a biped, like long-legged Bergamodactylus and Sharovipteryx. We have individual pedal traces for anurognathid pterosaurs. No trackways yet. And no forelimb marks either.

So, the anurognathid could not fly,
but PIN 2585/4 was still a strong flapper. There is nothing reduced about its sternal complex and pectoral girdle. We can image it running and flapping for added thrust, something like Cosesaurus did before the advent of wings in the Middle Triassic (Fig. 4).

Figure 2. Cosesaurus running and flapping - slow.

Figure 4. Cosesaurus running and flapping – slow.

The forelimbs are gracile
in PIN 2585/4 with shorter elements. unlike its more typical closest known sister, CAGS IG 02-81, which was clearly volant and had shorter hind limbs.  The fore claws of virtually all flying pterosaurs were capable of touching the ground (Fig. 5).

The CAGS IG 02-81specimen attributed to Jeholopterus

Figure 6. The CAGS IG 02-81 specimen attributed to Jeholopterus. Currently it nests  the sister to the flightless anurognathid. Note the proportional differences.

All of the skeletal elements
in PIN 2585/4 resemble those in sister taxa, except the proportions of the fore and hind limbs. Note that the orbits are in the back of the skull, as in CAGS IG 02-81 and ALL other pterosaurs — in contrast to the misinterpretation offered by Bennett (2007) for the flathead anurognathid that has been widely and erroneously accepted.

Figure 6. The flightless anurognathid, PIN 2585/4, is the same size as other typical anurognathids, but its long legs make it taller.

Figure 7. The flightless anurognathid, PIN 2585/4, is the same size as other typical anurognathids, but its long legs make it taller. Click to enlarge.

Here’s how it went down today:
When I first saw the image on Google, I wondered what that fossil was… and then I saw that familiar tail and foot of Sordes… and then I realized this is the long sought double pterosaur fossil! I wasn’t expecting the specimen to be flightless, but it soon dawned that the proportions indicated we had a second flightless pterosaur here. So, a very exciting day all around. If this has been published elsewhere, please let me know. I am not aware of it.

I would have published on this find, except…

  1. It’s not my fossil.
  2. I haven’t seen or studied the specimen first hand.
  3. And even if I had, as I’ve done on several specimens before,  past experience tells me that today’s pterosaur referees don’t want me publishing any more. Apparently they want to save the discoveries for themselves.
  4. Apologies if someone else is working on this specimen and/or is awaiting publication. I am not aware of anyone doing this.

The PIN 2885-4 specimen has been sitting around for 45 years.
They had their chance. This blog has made a habit of finding discoveries in overlooked and ignored specimens. And once again I demonstrate that you don’t have to see the specimen or have a PhD to make a contribution. Recognition is something else altogether.

References
Bakhurina NN 1988. [On the first rhamphorhynchoid from Asia: Batrachognathus volans Riabinin 1948, from Tatal, western Mongolia]. Abstract of paper in Bulletin of the Moscow Society for the Study of Natural History, Geological Section 59(3): 130 [In Russian].
Rjabinin AN 1948. Remarks on a Flying Reptile from the Jurassic of Kara-Tau. Akademia Nauk, Paleontological Institute, Trudy 15(1): 86-93.
Sharov AG 1971. New flying reptiles from the Mesozoic of Kazakhstan and Kirghizia. – Transactions of the Paleontological Institute, Akademia Nauk, USSR, Moscow, 130: 104–113 [in Russian].

wiki/Sharovipteryx

wiki/Batrachognathus

 

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