Megaraptor

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda > Tetanurae > Avetheropoda > Coelurosauria > Tyrannosauroidea (?) > Megaraptora > Megaraptoridae

Overview: In the mid-1990’s, a team of Argentine paleontologists came across the partial remains of a decently large theropod dinosaur, previously unknown to science. The recovered fossils would include bits of the arms, hands, and feet, but most notably, a gigantic claw measuring about thirty-five centimeters in length (fourteen inches). Argentine researcher Fernando E. Novas described the remains in 1998, assigning the generic name of Megaraptor, or “large thief”. The name was chosen in reference to the Dromaeosauridae, the infamous “raptor” family containing well known dinosaurs like Deinonychus and Velociraptor, and to its comparative larger size. Novas didn’t assign it to the Dromaeosauridae specifically, but he thought his new genus was related to them in some way, sharing a common ancestor. If it were a dromaeosaurid, then Megaraptor would easily be the largest known member of the family, growing to be up to eight meters in length. Earlier depictions of Megaraptor draw on its supposed link to the dromaeosaurids, with the large, sickle-shaped claw being placed on its second toe – a common trait of Velociraptor and its kin

The discovery of more complete fossils of Megaraptor and of its close relatives would prove that it wasn’t closely related to the dromaeosaurids, but a member of an entirely separate lineage known as the Megaraptora and, more specifically, the family Megaraptoridae. Notable members included Australovenator and Tratayenia. The supposed toe claw was actually affixed to one of its fingers. Megaraptorans tended to have proportionately long and muscular arms, their claws being the main killing implement for these predators. Their jaws were comparatively weak, long and slender. Being lightly built for their size, megaraptorans were probably surprisingly agile. Debate surrounds exactly how Megaraptor and its kin should be classified. Some older studies have placed them close to the genus Neovenator, in the allosauroid superfamily, but more recent studies have found them to be a part of the Coelurosauria, so closer to birds. They may’ve been a lineage of tyrannosauroids, but this is uncertain. Fossils of Megaraptor are known from Argentina’s Portezuelo Formation, so it lived in a seasonal floodplain alongside other dinosaurs like Unenlagia and the giant Futalognkosaurus.