Mapusaurus

Phylogeny: Dinosauria > Saurischia > Theropoda > Neotheropoda > Tetanurae > Avetheropoda > Carnosauria > Allosauroidea > Carcharodontosauria > Carcharodontosauridae > Carcharodontosaurinae > Giganotosaurini

Overview: Closely related to the infamous Giganotosaurus, Mapusaurus was a theropod nearly as large from the same general region of Argentina. Mapusaurus came from somewhat younger rock layers, within the Huincul Formation, as opposed to Giganotosaurus in the Candeleros Formation. Phylogenetic studies classify these two dinosaurs within the family Carcharodontosauridae, which made them derived members of the allosauroid superfamily. Specifically, Mapusaurus is referred to the tribe Giganotosaurini. Tyrannotitan is another notable member of this group, though it lived at least ten million years earlier than Mapusaurus. Some of the largest theropods known to science belonged to the Giganotosaurini. Mapusaurus itself grew to be ten to twelve meters in length and half a dozen standard tons in weight, at the very least. Mapusaurus and its kin had enormous skulls and short, but powerful arms, each hand equipped with three prominent claws. Along the snout of these animals were often low ridges of bone, which were quite prominent on Mapusaurus. In life, these may’ve been coated in keratin, further extending them and possibly bearing bright colors.

We can be fairly confident that Mapusaurus was the top land predator of its local environment, in the same way Giganotosaurus had been a few million years prior. The two can be distinguished by a few minor traits. Mapusaurus tended to have a shorter snout and somewhat taller neural spines on its vertebrae, for instance. Size estimates between the two are very close, though Mapusaurus was on average somewhat smaller. It coexisted with the massive sauropod Argentinosaurus, which may’ve been a food source, though fully grown adults would’ve been a challenge to bring down. In some cases, Mapusaurus skeletons have been found next to each other, which could imply it lived or even hunted in groups, which could’ve allowed it to tackle such large prey. Mapusaurus was first described as a genus in 2006, taking part of its name, meaning “earth lizard”, from the language of the local Mapuche people. The specific name of the type species, Mapusaurus roseae, combines with the generic name in reference to how it was found, encases in rose-colored sediments. This dinosaur is based on a decent number of individual skeletons of different growth stages.