Wooster’s Fossil of the Week: A holey brachiopod (Lower Cretaceous of southeastern Spain)

February 26th, 2012

This striking and unusual brachiopod is Pygites diphyoides (d’Orbigny, 1847) from Hauterivian (Lower Cretaceous) of Cehegin, Murcia, Spain. Wooster acquired it through a recent generous exchange of brachiopods with Mr. Clive Champion in England. I had heard about this brachiopod genus with a hole through its shell, but never before actually seen one. Thank you very much, Clive.

Pygites diphyoides is a terebratulid brachiopod, an order that is still in existence today. It is commonly called a “keyhole brachiopod” because of the perforation running vertically through the shell. It attached to the substrate with a pedicle (a stem-like device protruding through the pointy end of the shell). Pygites and its relatives appear to have been adapted deep sea, poorly oxygenated conditions, although they are found in shallower facies as well (Dieni and Middlemiss, 1981; Kazmer, 1993; Michalik, 1996).
In this reconstructed cross-section of Pygites (from Michalik, 1996, fig. 4) we can see how the central perforation may have helped with the flow of nutrient-bearing currents through the shell. (Although I must admit to being a bit baffled by the arrows!)
Pygites diphyoides was orginally described as “Terebratula diphyoides” in 1847 by the famous French naturalist Alcide Charles Victor Marie Dessalines d’Orbigny (1802-1857). He was a prolific scientist in many fields, including paleontology, general geology, zoology, archaeology and anthropology. D’Orbigny was a native Frenchman who grew up on the Atlantic coast of his country. He was especially fascinated with marine organisms, even giving the name (in 1826) to a group of protists we now know as “foraminiferans“. He was a proponent of the ideas of his countryman and esteemed zoologist Georges Cuvier during what were exciting times in the development of zoology and paleontology. He was an astonishingly productive scientist, with dozens of reports, papers and books to his credit, and he accumulated a spectacular collection of fossils and zoological specimens. D’Orbigny combined geology and paleontology in very useful ways, becoming one of the earliest biostratigraphers. As a Cuvier disciple, though, he believed the rock record showed a series of successive catastrophes and new creations, so he rejected the developing ideas of evolution during his lifetime (Taylor, 2002).

In 1853 d’Orbigny became professor of paleontology at the Paris Muséum National d’Histoire Naturelle, a new chair created for him. He died at the shockingly young age (for me!) of 54 years.

My friend Paul Taylor at the Natural History Museum in London knows the work of Alcide d’Orbigny very well, and is an expert in his voluminous collections of bryozoans, which you can read about at the link. You will see that the legacy of d’Orbigny is a bit mixed when it comes to his taxonomic contributions, so Paul has his challenges when it comes to sorting out the many names and descriptions this active scientist produced.

References:

Dieni, I. and Middlemiss, F.A. 1981. Pygopid brachiopods from the Venetian Alps. Bollettino della Societá Paleontologica Italiana 20: 19–48.

Kazmer M. 1993. Pygopid brachiopods and Tethyan margins. In: Palfy, J., Voros, A. (eds.), Mesozoic Brachiopods of Alpine Europe. Hungarian Geological Society, Budapest, pp. 59-68.

Michalik, J. 1996. Functional morphology – paleoecology of pygopid brachiopods from the western Carpathian Mesozoic. In: Copper, P. (ed.), Brachiopods: proceedings of the third International Brachiopod Congress, Sudbury, Ontario, Canada, 2-5 September, 1995. CRC Press.

d’Orbigny, A. 1847. Pal. franc., terr. crét., 4, p. 87, pl. 509. Barreme, Lieous, Berrias, Mons, près d’Alais.

Taylor, P.D. 2002. Alcide d’Orbigny (1802-1857). The Linnean 18: 7-12.

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