Greg Laden's Blog

Excavations at the same locality in 2003 recovered much more material from this species. Now, a team working mainly at a lab in Penn State has put all the pieces together to make a detailed reconstruction of the bony bits of this extinct lemur. The results are reported in an Open Access article published in the Proceedings of the National Academy of Science.

Using scans from a number of fragments and mirror imaging, a virtual skull (shown above) has been created, but this all required combining the earlier Austrian collection as well as the more recent excavation results.

According to Timothy Ryan, of Penn State University, "From the moment we combined the two datasets it was obvious that the fossils all belonged to the same individual. Because the newly-discovered fragments fit into the skull so cleanly, we decided to attempt a more thorough virtual reconstruction, filling in other missing pieces using the CT data or making mirror images of undamaged sections to restore damaged ones. ... This is very much a modern research story. We did all the work with the help of computers and neither all of the scientists nor all of the specimens were ever in the same room."

For the first time, the cranial capacity has been estimated for this species (115 cc), and using postcranial material excavated in 2003, it is now estimated that this lemur was about the size of a baboon. From a press release:

The skull shape of Hadropithecus is unusual. Its skull vault sports a large, bony crest -- similar to that seen on gorillas -- for the attachment of powerful chewing muscles. With big chewing muscles, a deep jaw, and a flat face, the skull of Hadropithecus seems mechanically suited to eating hard foods, such as seeds or nuts. This idea is supported by microwear studies showing that the enamel of the Hadropithecus teeth is heavily pitted and scratched. However, while other animals that feed on hard objects have thick dental enamel and interwoven enamel prisms that prevent tooth breakage, Hadropithecus does not.

Analysis of nitrogen and carbon isotopes in the bones of other specimens of Hadropithecus suggests a diet high in tough, fibrous succulents, tubers, or grasses -- not nuts or seeds. The team is investigating whether grit clinging to such plants in Madagascar would create the observed microwear pattern.

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