Baryonyx

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda > Tetanurae > Megalosauroidea (?) > Spinosauridae > Baryonychinae

Overview: Spinosaurid fossils, specifically those of Spinosaurus itself, have been known to science for over a century, but what exactly the spinosaurids were has only become clear within the past few decades. Spinosaurus was described on very limited fossils, which were later lost during World War II. Restorations of the animal often depicted it as an allosaur or megalosaur-like animal with a short, deep snout, albeit with a giant sail. It wouldn’t be until Baryonyx was discovered, in the early 1980’s, that researchers began to piece together what spinosaurids actually looked like. Fossilized remains of the animal were first collected by the amateur fossil hunter William J. Walker, in what is now the south of England. The first of these bones was a massive claw, but more fossils were later recovered from a local clay pit. Paleontologists would later secure the find, determining that it was of a brand new genus of theropod dinosaur. Based on these fossils, consisting of a partial skeleton, the genus Baryonyx was established in 1986, its name meaning “heavy claw”, in reference to the giant claw recovered by Walker. Walker himself is honored by the type species – Baryonyx walkeri.

Baryonyx was a highly unusual dinosaur at the time of its discovery. It was decently large, possessing fairly strong arms with three claws on each hand, the largest being affixed to the thumb. The skull was unusually elongated and slender, like that of a modern gharial, the jaws lined by conical teeth, similar to those of crocodilians. At the tip of the upper jaw was a notch that paired with a bulge in the bottom jaw’s tip. All of these traits suggested Baryonyx was mainly piscivorous, eating aquatic prey, specifically fish. Notched jaws, like those of actual crocodiles, create a trap to catch slippery prey. Fish scales in its gut region prove this, but we also know it fed on terrestrial animals. When it was first described, the classification of Baryonyx was uncertain, but later studies proved it was a member of the Spinosauridae. It lacked the large sail of its more famous relative, though its neural spines were relatively elongated, possibly supporting a low ridge. Baryonyx is specifically a member of the subfamily Baryonychinae, alongside dinosaurs like Suchomimus. Fossils are known from the Weald Clay and other formations, though some of these may belong to distinct, but related taxa.