02 April 2011

Fossil Vertebrate of the Month: Baryonyx walkeri

Last month's fossil vertebrate was an Irish icon, so in honor of April's St. George's Day, it only seems fair to put the spotlight on an English animal.  The earliest dinosaurs to ever be described were English, but for the most part the end of the Victorian Era was also the end of new dinosaur discoveries in Great Britain.  A few new taxa have come to light in the previous few decades, though, perhaps the most impressive of which is the bizarre Baryonyx walkeri.  Uncovered in Surrey in 1983 and named in 1986, the genus name translates as 'heavy claw,' a reference to the large, recurved claws on the animal's hands.  The other noteworthy feature of Baryonyx is its elongated skull with a kinked jaw, remarkably similar to that of a crocodile.  This skull, in conjunction with fish scales found within the specimen's body cavity, led to the conclusion (since challenged by some, but still largely accepted) that Baryonyx was piscivorous.  It's unusual morphology meant that the relationship of Baryonyx to other dinosaurs remained a mystery for some years, though the discovery of similar dinosaurs have shown that it was a member of the Spinosauridae, a group of large (in at least one case very large), sometimes sail-backed, likely fish-eating group of theropods that lived mainly on the southern continents during the Cretaceous.  Baryonyx was very closely related to the much-publicized African spinosaur Suchomimus tenerensis; in fact, the two were likely members of the same genus.

No comments: