Paleontologists have unearthed what may have been the most terrifying fisheater in history: a 3-meter-tall dinosaur that sported claws like giant meat hooks and a crocodilelike snout. The discovery of this beast, described in tomorrow's Science, sheds light on the evolution of a peculiar group of dinosaurs called the spinosaurids.
Spinosaurids are a poorly known subset of theropods, two-legged carnivores such as Tyrannosaurus and Velociraptor. The first specimen was unearthed in Egypt in 1912, but destroyed during the bombing of Munich in World War II. Additional bones of Spinosauruslike predators have since turned up in Niger, Brazil, and Europe. But recently, an international team of paleontologists led by Paul Sereno of the University of Chicago found a relatively complete specimen in the Ténéré Desert of central Niger. By analyzing the new fossil, which they have christened Suchomimus tenerensis, Sereno and his colleagues have determined that the 100-million-year-old spinosaurid skull is even more elongate and crocodilian than previously thought.
The find could force major revisions to the history of spinosaurids, which were thought to have evolved into separate species in the Southern and Northern hemispheres. The African Suchomimus appears to be more closely related to a northern spinosaurid, Baryonyx of Europe, than to the southern spinosaurids found in Egypt and Brazil. These northern dinosaurs may have colonized Africa via a land bridge across the Tethys seaway, located in what is now the mid-Atlantic Ocean. "This finding will add significant information to the idea that there was traffic across the Tethys seaway during the Cretaceous Period," says Sereno.
A striking feature of the skull is its similarity to ancient crocodilians, implying a fish-eating diet, says Thomas Holtz of the University of Maryland, College Park. The narrow snout, for example, might permit a smoother passage through rivers and lakes, and the cone-shaped teeth would allow the dinosaur to better pierce and grasp a slippery fish. These adaptations may have allowed Suchomimus and other spinosaurs to exploit a fishy food source untapped by other large carnivores, he says.