What is Brouffia? – A short series – part 2
Yesterday we looked at two very different interpretations of the skull of Brouffia orientalis, neither of them mine. Today, here’s the post-crania in situ, part and counterpart (Fig. 1, click to enlarge it) presented by Brough and Brough (1967, one view flipped for comparisons).
Sorry we’re taking it so slow. Lots going on over here, including Christmas shopping. I’m also hoping someone out there will send a good photo of the specimen to put under DGS.
Figure 1. Click to enlarge. Quite close to the earliest known reptile, phylogenetically, the only fossils of Brouffia are known from the Late Carboniferous. Was it a reptile? Or a close runner-up? The twin tops on the ilium are otherwise only known in pre-reptiles. If an intertemporal was present, as Brough and Brough (1967) interpret the skull, that would confirm its pre-reptile status. However if the inter temporal was gone, having fused to the parietal, as Carroll and Baird (1972) see it (above), then the phylogenetic picture is muddied.
Brough and Brough (1967) published large tracings of tiny Brouffia (which they considered a specimen of Gephyrostegus). The lack of complete ossification in the pelvis and pectoral girdle argues for an immature status in this specimen. The presence of complete ossification in the carpus argues for a mature status. Was this a small adult? Or a well-ossified (but only in certain places) juvenile? Related forms, including Cephalerpeton and Casineria did not have a coosified pectoral girdle, but others did.
No intercentra have been observed, but they may have been poorly ossified. The spaces between the centra are beveled to receive them.
Brough and Brough (1967) restore the manus with short digits. I found the hand to be longer and more asymmetric (Fig. 1), matching those of related taxa and those several nodes away.
Brough and Brough (1967) reported two sacrals, making it more reptilian. Carroll and Baird (1972) reported only one. The pelvis is unknown in Cephalerpeton, but it is more reptilian looking in the non-reptile Gephyrostegus than in Brouffia. Odd that the coracoids appear to be missing.
More later.
As always, I encourage readers to see specimens, make observations and come to your own conclusions. Test. Test. And test again.
Evidence and support in the form of nexus, pdf and jpeg files will be sent to all who request additional data.
References
Brough MC and Brough J 1967. The Genus Gephyrostegus. Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences 252 (776): 147–165. doi:10.1098/rstb.1967.0006
Carroll RL and Baird D 1972. Carboniferous Stem-Reptiles of the Family Romeriidae. Bulletin of the Museum of Comparative Zoology 143(5):321-363. biodiversitylibrary
2012-12-18 06:39:18
Source: http://pterosaurheresies.wordpress.com/2012/12/18/what-is-brouffia-a-short-series-part-2/
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