Monday, February 6, 2012

Tapejara wellnhoferi: the lost reconstructions

Ross A. Elgin

Only twenty three years after it was formally named Tapejara wellnhoferi [1], one of the best known azhdarchoids from the Araripe Basin of NE Brazil, finally has a body! While, if I’m honest, this isn’t exactly new news, the original publication being released in the Swiss Journal of Palaeontology by my colleague Kristina Eck towards the end of last year [2], there is at least some merit to a post looking back at this particular discovery.

For a start, in case you missed it the first time around, the specimen is very unusual in that the remains of two juvenile pterosaurs – one largely complete and one represented by a partial wing, became embedded together within a single nodule. To the best of my knowledge the original concretion thus represents the only example of a multiple death assemblage in pterosaurs where neither specimen has been reworked from another layer of strata; a factor almost certainly attributable to the low preservation potential of the pterosaurian skeleton coupled with the presumably large geographical distance throughout which these animals were capable of being dispersed. Whether this unusual taphonomy was brought about by two unlucky individuals being downed during a storm, swept in from a nearby nesting site or simply as a result of local water currents, however, remains very much an open and unanswerable question.

Although numerous azhdarchoid postcrania are known the Early Cretaceous of Brazil they are almost always indeterminate owing to the lack of the skull and so remain of limited taxonomic value (to the great frustration of both myself and I’m sure other palaeontologists working on these animals). With this in mind the most valuable information that these two individuals are able to provide is a detailed look at the postcranial skeleton in a species so often defined solely by its cranial remains, and based on this the first reconstruction of T. wellnhoferi is presented here. The reconstructions posted below were originally destined to be included with the original description, however, were unfortunately cut due to space restrictions in what was an already overly long research paper. While it is thus worth noting that these diagrams have not been reviewed by the wider scientific community I nonetheless feel it best to present them here for reference and the benefit of future researchers or other interested parties.





Figure 1. Tapejara wellnhoferi reconstructed from skeletal material of SMNK PAL 1137 in left lateral view. Forearm and tibia/pes omitted for clarity. Bones shaded in grey indicate preserved elements.


Figure 2. Tapejara wellnhoferi reconstructed from skeletal material of SMNK PAL 1137 in ventral view. Bones shaded in grey indicate preserved elements. Left side of the body omitted to increase visibility.

So there we have it, in addition to some nice notes on the endocranial cavity and pneumatic system, for which I don’t have space to delve into here, Tapejara wellnhoferi finally gets its body and we can all enjoy a long awaited reconstruction of the animal, along with some interesting thoughts on pterosaurian taphonomy.

References

1. Kellner, A. W. A. 1989. A new edentate pterosaur of the Lower Cretaceous from the Araripe Basin, Northeast Brazil. Anais de Academia Brasileira de Ciencias 61:439-446

2. Eck, K., Elgin, R.A., Frey, E. 2011. On the osteology of Tapejara wellnhoferi KELLNER 1989 and the first occurrence of a multiple specimen assemblage from the Santana Formation, Araripe Basin, NE-Brazil. Swiss Journal of Palaeontology, doi: 10.1007/s13358-011-0024-5.

4 comments:

  1. Are the cast skeletons flapping around various museums based on this specimen?

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  2. "The reconstructions posted below were originally destined to be included with the original description, however, were unfortunately cut due to space restrictions in what was an already overly long research paper."

    Do you mean Kellner's seven-pager, cited as reference 1 above? Hardly seems "overly long" to me.

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  3. This comment has been removed by the author.

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  4. Incidentally, I think there's a screwup in the paper. The element described and figured as the prepubis is actually the postacetabular process of the ilium. It's shown correctly as this in the diagram above. Mike: Ross is obviously referring to his own paper. It is unfortunate (and odd) that the reconstructions couldn't be included therein.

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