Sunday, 2 August 2009

Resolving Criorhynchus

In 1861, a new species of pterodactyl was published by Richard Owen. The specimen was the end of a snout with a couple of teeth and 5 tooth sockets. He called this specimen Pterodactylus simus. A few years later he assigned the specimen to a new genus Criorhynchus simus. Harry Govier Seeley also published the specimen as Criorhynchus simus and added other specimens of anterior jaw fragments to this genus.

Several upper jaw snouts were discovered from the Upper Greensand. This is a derived deposit which contains lots of fragmentary remains. The nature of this pterosaur was not well known and analysis of the remains were very speculative at the time.

With no associated remains Criorhynchus was just a series of similar snouts. For many years the consensus was that this was a short snouted large pterosaur with a solid jaw and a very powerful bite.

It was not until 1987 when Peter Wellnhofer described a specimen from Brazil which he called Tropeognathus mesembrinus. This was one of those inspirational discoveries which put the Criorhynchus specimens into context. These species were interpreted as skim feeders with an aqua dynamic snout tip crest.
With increasing fossil evidence, this specimen was later re-assigned to the genus Anhanguera by Kellner and Campos in 1989.

Many pterosaur finds tend to follow this pattern of discovery and rediscovery. This is how science works. There are draws full of unassigned pterosaur specimens in museums around the world waiting for that magic moment when someone makes a discovery or a link that helps to put them into their correct context. Finding such resolutions is a joy.

Owen, R. 1861 Monograph on the fossil Reptilia of the Cretaceous Formations. Supplement III. Pterosauria (Pterodactylus). The Palaeontographical Society, London. (volume for 1858; pp. 1–19 & pls 1–4)

Owen, R. 1874 A Monograph on the Fossil Reptilia of the Mesozoic Formations. 1. Pterosauria. The Palaeontographical Society, London. pp. 1–14 & pls 1–2.

Wellnhofer P; 1987, New Crested Pterosaurs from the Lower Cretaceous of Brasil, Mitteilungen der Bayerischen Statssammlung fur Paleontologie und historische Geologie, 27: 175-186 Munchen

Kellner, A. W. A. & Campos, D. de A. 1990, Preliminary description of an unusual pterosaur skull of the Lower Cretaceous from the Araripe Basin. Atas I. Simp. sobre a Bacia do Araripe e Bacias Interiores do Nordeste, pp. 401–405.

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