'large thief') is a genus of large theropod dinosaur that lived during the Turonian and Coniacian ages of the Late Cretaceous.

The type specimen of Megaraptor consists of a fragmentary assemblage of limb bones, discovered in 1996 by Argentine palaeontologist Fernando E. Novas.

Believing that a large claw found at the site came from the animal's foot, he determined that it was probably a coelurosaur related to dromaeosaurs and troodontids, and named it accordingly.

The specimen, catalogued as MCF-PVPH 79, was transported to the Museo Carmen Funes, a palaeontological collection in Plaza Huincul.

[1] In December 1997, Novas presented a cast of the ungual, which he believed to come from the second digit of the foot, to the Houston Museum of National Sciences.

Believing that the new taxon was somewhat related to dromaeosaurids and troodontids, (though noting that a more basal position was possible), Novas gave it the binomial name Megaraptor namunhuaiquii.

[7] The skull of Megaraptor is known from a single juvenile specimen, which preserves both premaxillae and maxillae, nasals, a left frontal, and a partial braincase.

Similarly, the nasal rugosities present in other many other basal tetanurans are absent, though this may again be due to the specimen's age upon death.

The neural spine of the axis (the second cervical vertebra) was tall and narrow, with a convex dorsal margin, resembling basal coelurosaurs like Scipionyx, while differing from allosauroids and derived tyrannosauroids.

The first four neural spines were short dorsoventrally (top-to-bottom) and anteroposteriorly (front-to-back), while those further along the vertebral column were longer and taller.

[3]The pectoral girdle of Megaraptor differed from that of carcharodontosaurids in that its scapula was slenderer, and the acromial process was shallower, though resembled that of Allosaurus.

[3] Roger B. J. Benson, Matthew T. Carrano and Stephen L. Brusatte erected the clade Megaraptora to encompass Megaraptor and its closest relatives.

[11] The 2014 paper describing a juvenile Megaraptor suggested, based on a phylogenetic analysis, that megaraptorans were nested within Tyrannosauroidea.

(UNPSJB-Pv 944/958) Orkoraptor Maip Megaraptor is known from the Late Turonian to Early Coniacian-dated Portezuelo Formation of Argentina.

Fossils of teleost fish (Leufuichthys), turtles (Portezueloemys and a species of Prochelidella), birds, and pterosaurs (Argentinadraco) are also known.