The one and only pterosaur skeleton at Washington University

The Earth and Planetary (formerly Geology) Department at Washington University in St. Louis, Missouri, USA is famous for seismology, planetary chemistry and Mars rovers. Paleontology used to be a big deal, but with the retirement of Dr. Hal Levin, not so much anymore. Dinosaur hunter Joshua Smith was here for a short time, but that fizzled. Wash U still has a great geology library where I recently came to know Kaikaifilusaurus and Herbstosaurus in the stacks.

The Wash U collection consists of some spectacular specimens of Mastodon, crinoids, ichthyosaurs and a really big Pliocene croc, all the latter from Europe. There are some Solnhofen fish and one lonely, roadkill pterosaur, correctly labeled, Rhamphorhynchus phyllurus (Fig. 1).

Figure 1. Click to enlarge. Color enhanced stitched photo (taken with IPhone) of the one and only pterosaur fossil (WU970001) at Washington University in St. Louis.

Figure 1. Click to enlarge. Color enhanced stitched photo (taken with IPhone) of the one and only pterosaur fossil (WU970001) at Washington University in St. Louis. Note the damaged wing tip at left. Only a few skull parts are here, but strangely, no sacrum, pelvis or prepubis is present, although the hind limbs were left behind.

Just an ordinary Rhamphorhynchus with an “ouchee”
WU 970001 is a fairly typical Rhamphorhynchus. It has several distinct features, so is not identical to any Rhamph already tested. And it has a bent wing tip.

Figure 2. Sometimes it helps to reconstruct roadkill fossils like the Washington University Rhamphorhynchus WU 970001.

Figure 2. Click to enlarge. Sometimes it helps to reconstruct roadkill fossils like the Washington University Rhamphorhynchus WU 970001.

Figure 3. Segment of the large pterosaur tree focusing on Rhamphorhynchus.

Figure 3. Segment of the large pterosaur tree focusing on Rhamphorhynchus.

The Wash U specimen nests with the famous Yale specimen (n33), but lacks wing membrane preservation. Strangely, the pelvis and prepubes are missing. The skull is also largely gone.

One wing tip is strongly bent, likely broken and rehealed under the stress of the wing membrane. The wings were quite long. The sternal complex was quite large. The humerus and hind limbs were rather small. The pes has a unique combination of phalangeal ratios in the pattern of its closest kin, but matching none of them.

Like other Rhamphs, this one appears to have been a very able flyer, with large anchors for wing muscles and long wing phalanges, including the m4.4, which was slightly longer than m4.3.

Forelimb launch?
Seems unlikely that such a small humerus could launch this specimen high enough to bring those big wing fingers cycling around. Better, perhaps, to stand bipedally and launch like a bird using a combination of a hind limb leap and large flapping wings.

So how does a specimen lose its pelvis and sacrum?
I have no idea.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.