What big teeth you have, Fido

Discovery

Courtesy: Hans Larsson

It’s not often that old bones make worldwide headlines, but the discovery of the remains of a very peculiar-looking crocodile did just that this summer.

In the July issue of the science journal PLoS One, Hans Larsson, BSc’94, McGill’s Canada Research Chair in Vertebrate Palaeontology, and his colleagues described the long-extinct Pissarrachampsa sera crocodile, a beast shaped more like a dog than any crocodile. Previously, almost nothing was known about these crocs.

“Their fossils were hidden away in politically charged areas most researchers hadn’t been able to see,” explains Larsson. Following on the discovery of a collection of five fossils in Brazil, however, Larsson and his team (which included graduate student Felipe Montefeltro) have mapped the crocodile in extreme detail.

A member of the previously misunderstood Baurusuchia grouping of crocodiles, the creature bears no resemblance to any previously known animal.

“They were nothing like living crocodiles today,” says Larsson. “They were not amphibious, they weren’t crawling on their bellies, they didn’t have low, flat skulls, and they didn’t have a lot of teeth.”

Instead, they walked—or bounded —atop their legs, like dogs, and ate with teeth like those of a sabre-toothed tiger.

Larsson and his team have continued to explore the fossils, most recently by subjecting them to CT scans at the Jewish General Hospital. “The data is just extraordinary,” says Larsson. “We’re now reconstructing the areas inside the skull, including the brain-space, to get an idea of the size and shape of the brain. This allows us to get a sense of whether certain parts of the brain were more developed—for example, the areas for sight, or smell, or balance.” They are in the process of preparing several more articles expanding their findings, which have completely changed the science world’s understanding of Baurusuchia crocodiles.

Jesse Staniforth, BA’01, MA’03

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