Dryptosaurus

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda > Tetanurae > Avetheropoda > Coelurosauria > Tyrannosauroidea > Pantyrannosauria > Eutyrannosauria > Dryptosauridae

Overview: Dryptosaurus today is a somewhat obscure dinosaur, but back when its fossils were first discovered, it was quite the significant find. Said bones were unearthed in the 1860’s, back when it had yet to be fully established that theropods, such as Megalosaurus, were bipeds. Dryptosaurus, like Megalosaurus, was known from very limited material. This included some jaw bones, parts of its limbs and at least one enormous claw. However, enough of the limbs were found to prove it was bipedal. These fossils were first described in 1866 by the American paleontologist Edward D. Cope, who gave it the binomial label of Laelaps aquilunguis - the generic name referring to a hunting dog from Greek myth and meaning “hurricane” or “whirlwind”. Its specific name means “eagle-clawed”, referring to the aforementioned claw, which Cope placed on its feet. Still, Cope would oversee a famous painting of the animal, created by the renowned early paleoartist Charles R. Knight, which depicted it as unusually active and dynamic for a dinosaur reconstruction from the 1890’s. Knight, perhaps at Cope’s insistence, would name the painting after his original generic name, naming it Leaping Laelaps.

Laelaps would turn out to be a name already in use for another animal, namely a genus of mite, so it had to be changed. To Cope’s consternation, his hated rival Othniel C. Marsh would officially rename the genus in 1877, coining the name Dryptosaurus, or “ripping lizard”. This name, like the specific name, refers to its claws. Back then, Dryptosaurus was usually classified as a relative of Megalosaurus, in the family Megalosauridae. We know today that it was actually a lot closer to Tyrannosaurus, belonging to the same tyrannosauroid superfamily. Dryptosaurus tends to be classified just outside the family Tyrannosauridae itself, as a basal eutyrannosaur, within its own family - the Dryptosauridae. The claw that Cope believed was a toe talon was actually on its hands. Some reconstructions have depicted it with three fingers, but most now believe it had only two digits, similar to Tyrannosaurus. Unlike Tyrannosaurus, Dryptosaurus still possessed fairly long and quite powerful arms. Its skull was more slender, suggesting a different hunting strategy. The two lived at around the same time, but Dryptosaurus lived across a narrow seaway to the east, in the prehistoric and mysterious Appalachian landmass. Dryptosaurids dominated this region while the more derived tyrannosaurids did so in the western landmass of Laramidia.

Leaping Laelaps

Leaping Laelaps – Charles R. Knight, 1897

Here is the above mentioned painting of Dryptosaurus by Knight. Cope and some other researchers of his time picked upon the fact that dinosaur anatomy suggested they were likely far more active animals than your typical reptile. This view would fall out of favor by the 1920’s, partly because the idea of an evolutionary link between non-avian dinosaurs and birds fell out of favor, though at the end of the 1960’s it would see a resurgence.