Mapusaurus

Mapusaurus was a giant carnosaurian dinosaur from the early Late Cretaceous of what is now Argentina.

It was similar in size to its close relative Giganotosaurus, with the largest known individuals estimated as about 10.2 metres in length and weighing approximately 3 metric tons. The longest individual for which Coria and Currie provided an estimate is the animal to which femur MCF-PVPH-208.203 belonged; this individual is estimated as 10.2 metres long. Coria and Currie note the presence of isolated bones from at least one longer individual, but do not provide a figure, instead finding the larger bones comparable in size to those from a Giganotosaurus estimated at 12.2 metres in length. Maximum length is thus unknown but greater than 12.2 metres. The weight estimate is from another femur. It was furthermore concluded that the largest remain, a pubic shaft, was 110% the size of theGiganotosaurus holotype. Holtz estimated it at 12.6 metres. In an analysis on the cranial anatomy of carcharodontosaurids, Drew Eddy and Julia Clarke estimated the size of Mapusaurus at 12.6 metres. this estimate was repeated in a calibrated phylogenetic table in a 2014 analysis by Canale et al.

Coria and Currie diagnosed Mapusaurus as follows: "Mapusaurus n. gen. is a carcharodontosaurid theropod whose skull differs from Giganotosaurus in having thick, rugose unfused nasals that are narrower anterior to the nasal/maxilla/lacrimal junction; larger extension of the antorbital fossa onto maxilla; smaller maxillary fenestra; wider bar between antorbital and maxillary fenestrae; lower, flatter lacrimal horn; transversely wider prefrontal in relation to lacrimal width; ventrolaterally curving lateral margin of the palpebral; shallow interdental plates; higher position of Meckelian canal; more posteriorly sloping anteroventral margin of dentary. Mapusaurus roseae is unique in that the upper quadratojugal process of jugal splits into two prongs; small anterior mylohyoid foramen positioned above dentary contact with splenial; second and third metacarpals fused; humerus with broad distal end and little separation between condyles; the brevis fossa of the ilium extends deeply into excavation dorsal to ischial peduncle. It also differs from Giganotosaurus in having conical, slightly curving cervical epipophyses that taper distally; axial posterior zygapohyses joined on midline; smaller and less elaborate prespinal lamina on midline of cervicals; remarkably sharp dorsal margin of cervical neural spines; tall, wider neural spines; curved ischiatic shaft; more slender fibula".