Megaraptor

Megaraptor ("giant thief") is a genus of large theropod dinosaur that lived in the Turonian to Coniacian ages of the Late Cretaceous. Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina. Initially thought to have been a giant dromaeosaur-like coelurosaur, it was classified as a neovenatorid allosauroid in previous phylogenies, but more recent phylogeny and discoveries of related megaraptoran genera has placed it as either a basal tyrannosauroid or a basal coelurosaur.
Description.
"Megaraptor" was initially described as a giant dromaeosaur, known primarily from a single claw (about 30 cm long) that resembled the sickle-shaped foot claw of dromaeosaurids. The discovery of a complete front limb, however, showed that this giant claw actually came from the first finger of the hand. In 2010, Gregory S. Paul estimated its length at , its weight at . The hands were unusually elongated, bearing sickle-shaped claws even more recurved than those of spinosaurids.
Classification.
The hand is quite distinct from other basal tetanurans, so it was not initially clear whether "Megaraptor" was an allosaurid, a carcharodontosaurid, a spinosauroid, or something else entirely. Subsequent studies, as well as the identification of close relatives with similar large claws on the forelimbs (see below), helped identify "Megaraptor" as a highly advanced and lightly built allosauroid, and a member of the family Neovenatoridae. More recent studies have proposed that "Megaraptor" and its kin are actually tyrannosauroids or spinosauroids as opposed to allosauroids. A juvenile specimen described in 2014 has provided more evidence towards "Megaraptor" being a primitive tyrannosauroid. The discovery of "Gualicho" indicates that "Megaraptor" may not be a tyrannosauroid, but either an allosauroid or basal coelurosaur.
When first discovered and prior to publication, the spinosaurid "Baryonyx" was also reported to be a dromaeosaurid, and the allosauroid "Chilantaisaurus" was reported to be a possible spinosaurid, both based on the large hand claws.
The cladogram shown below follows an analysis by Porfiri "et al.", 2014.