Eurazhdarcho and LIPB R 2.395: two new azhdarchid pterosaurs

Two European azhdarchids
have become known recently. Eurazhdarcho langendorfensis EME VP 312/2 (Vremir et al. 2013, Fig. 2) and the unnamed LIPB R 2.395 (Vremir et al. 2015. Fig. 1). Eurazhdarcho is known from a distal mc4, a proximal m4.1 and a proximal mt3 (not a distal mc3 as originally labeled, see below), plus cervicals 3 and 4. LIPB R 2.395 is known from a cervical 4 only.

What little is known indicate that both are similar in size and proportions to Zhejiangopterus. And they are just as gracile.

Figure 1. LPB-(FGGUB)-R.2395 cervical 4 with other cervicals imagined.

Figure 1. LPB-(FGGUB)-R.2395 cervical 4 with other cervicals imagined.

The re-identification
of distal metacarpal 3 in Eurazhdarcho (Figs. 2, 3) as metatarsal 2, 3 or 4 is based on the shape of the bone in question. It is expanded asymmetrically proximally and flattened as preserved in situ in Eurazhdarcho (Figs 2, 3) and Quetzalcoatlus (Fig. 4). By contrast distal metacarpal 3 in all pterosaurs has a convex articular surface to accommodate an unrestricted metacarpophalangeal 3 joint permitting extreme extension for implanting posteriorly while walking.

Figure 2. Eurazhdarcho with mc3 reidentified as mt3.

Figure 2. Eurazhdarcho with distal mc3 (in red and in figure 3) re-identified here as proximal portion of metatarsal 2, 3 or 4.

The in-situ placement
of the bone in question (Fig. 2) on the fossil near metacarpal 4 cannot be valid evidence because the cervicals are also extremely displaced. These bones became a jumbled mess long after the body had disintegrated and these few scattered elements were fossilized.

Figure 3. Close up of bone labeled distal mc3. This looks more like proximal mt3.

Figure 3. Close up of bone labeled distal mc3 in Eurazhdarcho. This looks more like a proximal metatarsal in Quetzalcoatlus in figure 4. There is no spherical articulation surface here that would indicated a distal metacarpus. The pink area is a restoration that could represent a much longer distal metatarsal.

The metatarsus of Quetzalcoatlus (Fig 4)
provides comparable data for the Eurazhdarcho bone in question. Metatarsal 4 is shown because it shows better on the lateral edge of the foot. Metatarsal 3 lies beneath it. Both appear to be a good match.

Figure 3. Metatarsal 3 in Quetzalcoatlus looks like the same bone in Eurazhdarcho labeled as a distal metacarpal 3.

Figure 4. Metatarsal 3 in Quetzalcoatlus looks like the same bone in Eurazhdarcho labeled as a distal metacarpal 3. Click to enlarge.

Good to see
mid-sized azhdarchids in eastern Europe to go with the giant Hatzegopteryx, also known from scraps.

I sincerely hope
one of the authors of both papers, Darren Naish, is not too upset by this reinterpretation. We’ve heard from him before. I confess: I used DGS. Never saw the actual fossil. And I don’t have a PhD. Did I make a mistake? Let me know and a change will be made.

References
Vremir MTS, Kellner AWA, Naish D, Dyke G 2013. Laurent  V, ed. A New Azhdarchid Pterosaur from the Late Cretaceous of the Transylvanian Basin, Romania: Implications for Azhdarchid Diversity and Distribution. PLoS ONE 8: e54268.
Vremir MTS, Witton M, Naish D, Dyke G, Brusatte SL, Norell M and Totoianu R 2015. A medium-sized robust-necked azhdarchid pterosaur (Pterodactyloidea: Azhdarchidae) from the Maastrichtian of Pui (Haţeg Basin, Transylvania, Romania). American Museum Novitaes 3827 16 pp.

 

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2 thoughts on “Eurazhdarcho and LIPB R 2.395: two new azhdarchid pterosaurs

  1. Indeed, I’m not so sure (100%) about all the identifications (especially the tiny scraps). The mc/mt question is valid, and as soon as i have time, i will try to do some more prep work. However, the skeleton wasn’t so much dispersed, unless, a hind limb was banded over the body (lying on his back). Signs of scavenging are obvious, so anything is possible.
    Matyas

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