What is Gladocephaloideus?

Lü et al. (2012) recently reported on a new Gallodactylus (= Cycnorhamphus)-type of Ctenochasmatoid (cycnorhamphidae + ctenochasmatidae + Pterodactylus). Unfortunately these three clades are not related in the large pterosaur tree that tests many more possibilities.

gladocephaloideus-recon

Figure. 1. Gladocephaloideus in situ and reconstructed using DGS (digital graphic segregation). There is a lot of preserved skin and hair on the cranial and cheek parts of the skull (Fig. 2), which is cool, but it means the underlying bones are not as prominent.

Meet Gladocephaloideus jingangshanensis
This long rostrum ctenochasmatid did not have as many teeth as Ctenochasma, nor did it have the spoon-bill of Gnathosaurus. But it did have the slightly curved rostrum, widely spaced teeth and elongated neck vertebrae of Gegepterus. Gladocephaloideus lived during the Barremian stage of the Early Cretaceous some 125 million years ago, so it was a contemporary of Gegepterus from the same formation. From information presented so far, Gladocephaloideus may be a species within the genus Gegepterus.

Skull of Gladocephaloides

Figure 2. Skull of Gladocephaloideus in situ. (IG-CAGS-08-07). Skull length 18.2 cm. Note the soft tissue fibers emanating from the posterior skull. Part of the palate is visible between the jaws.

Soft Tissues
The back of the Gladocephaloideus skull includes, “Filamentous structures are preserved near the dorsal and posterior margins of the posterior portion of the skull (above the orbit), and similar structures are also preserved near the back side of the cervical vertebra. It also supports the idea that at least some relatively small pterosaurs were warm-blooded, active fliers.” As mentioned above, the cheek area is also covered by skin that obscures the underlying bones.

The pes of Gladocephaloideus

Figure 2. (Left) The pes of Gladocephaloideus compared to (right) the pes of Ctenochasma elegans (a smaller, more primitive Ctenochasma with fewer teeth than larger specimens in the genus Ctenochasma). The feet of Gegepterus are unknown.

The Feet Tell the Tale
No doubt the skulls of Gladocephaloideus and the cycnorhamphid, Feilongus (Fig.4), converge upon each other. Even so, the feet of Gladocephaloideus are much closer to those of other ctenochasmatids, like Ctenochasma elegans (Fig. 2) and AMNH 5147, a primitive gnathosaurid. The feet of cycnorhamphids are distinctly different with a longer metatarsal 1. Scaphonathids (including cycnorhamphids and ornithocheirids) also share a metatarsal 1 longer than the others.

The skull of Gegepterus,

Figure 4. The skull of Gegepterus, also from the Yixian formation of the Early Cretaceous of China. Note the similarities to the skull of Gladocephaloideus.

Parietal Crest?
Lü et al. (2012) reported an extremely low crest on Gladocephaloideus (Fig. 1). To me, that doesn’t look like much of a crest. Instead that zone may represent the crushed and broken occiput of a rounder skull, as in ctenochasmatids.

Parsimony
In the large pterosaur tree, Gladocephaloideus nests as a sister to Gegepterus and may be a species of that genus. To move Gladocephaloideus to the cycnorhamphids requires 28 more steps.

 

References
Lü J-C, Ji Q, Wei X-F and Liu Y-Q 2011. A new ctenochasmatoid pterosaur from the Early Cretaceous Yixian Formation of western Liaoning, China. Cretaceous Research in pressdoi:10.1016/j.cretres.2011.09.010.

wiki/Gladocephaloideus

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