Today we have a sort of double guest post with both Taissa Rodrigues and Fabiana Costa writing together on a recently named Australian pterosaur. Be prepared for some serious ornithocheirid taxonomy:
Not so long ago, Tamara Fletcher posted her ‘Lessons from a First Paper‘ on the Musings. It’s quite interesting how papers with subjects relevant to your own manuscript are published just when you think you are finally finished! It was fantastic to get the chance to read her very detailed paper and include the information before submission.
We have been wondering about Australian pterosaurs for a while. It has been thirty years since their first description and still all known material is very fragmented. Unless you have a very diagnostic piece of bone, fragmentary material creates taxonomic uncertainty. This was the case of the Australian material: almost all of it was in a sort of “ornithocheirid limbo”, where no one seemed to know exactly what it was.
Let’s take, for instance, the first mandible ever described from Australia. It has been referred as: Ornithocheirus, Anhanguera Lonchodectes and then again Ornithocheirus. Oddly enough, a couple of these referrals was based on a certain taxonomic review, but did not agree on the same name. So, what is this material?
In order to answer this question, we had to take a look at this specimen in different levels. First, we know that it is related to both Ornithocheirus and Anhanguera because it has teeth, an elongated mandibular symphysis, and a mandibular groove. So we can place it in the clade Pteranodontoidea, more closely related to its genera. The exact phylogenetic position is still undefined; as already stressed, the specimen is very fragmentary, and futhermore current pterosaur analyses include very few mandibular characters.
Second, is it Ornithocheirus, Anhanguera, or Lonchodectes? This is the part where we thank our funding agencies for all the travelling we had to do! Let’s take the type species Ornithocheirus simus. It is known by a very robust and massive upper jaw, quite unlike the lanceolated mandible of the Australian specimen. It seemed quite unlikely that such disparate specimens would represent the same genus, so we ruled it out. There are several species in Anhanguera and the taxonomy is controversial, so let’s consider just the type species, Anhanguera blittersdorffi… oops, no mandible in the type specimen, but there is a superbly preserved referred material whose mandible has a distal expansion and a nice mandibular crest. So, another genus ruled out. We had the chance to see all the species referred in Lonchodectes and, once again, the differences rose. As David Unwin has already pointed out in his review of the Cambridge Greensand pterosaurs, lonchodectids have a characteristic parapet-like palate, which is also absent in the Australian material. All these morphological characters, together with the different ages and distinct deposits, suggest that the Australian material could represent a new genus.
Our final question was: could it be a new species, or merely undiagnosable? There are plenty of lanceolated mandibles in the Cambridge Greensand, but none of them had the characters that this Australian piece has. Besides some differences in the distance and size of the dental alveoli, it is unique in that it has a convex dorsal margin and a straight ventral margin, the opposite of what we see in other pteranodontoid mandibles. Working with this material was a quite good exercise of comparison.
All things taken into consideration: unique characters, combination of characters, do not fit into a known genus, and the Australian material is typically fragmentary; we thought it deserved to be considered a new genus and species. We wanted to honour the person who not only described it thirty years ago, but also made a difference to Australian paleontology and named it Aussiedraco molnari.
Kellner, Alexander W.A.; Taissa Rodrigues and Fabiana R. Costa (2011). “Short note on a pteranodontoid pterosaur (Pterodactyloidea) from western Queensland, Australia”. Anais da Academia Brasileira de Ciências 83 (1): 301–308.