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05-22-2020, 08:35 PM( This post was last modified: 07-12-2021, 07:27 AM by DinoFan83 )
Giganotosaurus roseae was a giant carcharodontosaurid theropod from the early Late Cretaceous (late Cenomanian to early Turonian stage) of what is now Argentina. Just like some of its more famous relatives, G. roseae was one of the largest known theropods, with known specimens indicating an animal substantially heavier than Tyrannosaurus rex and very similar in size to the closely related Giganotosaurus carolinii. This species is commonly considered to be its own genus (Mapusaurus), but because this generic separation is based almost entirely on elements that the G. carolinii holotype does not preserve (making a proper judgement on almost all proposed differentiation between the 2 impossible), with the only differences noted in overlapping material being a less pneumatic quadrate and differently rugose nasals in G. roseae, Mapusaurus being a valid genus remains highly improbable unless a specimen of G. carolinii is discovered proving G. roseae to be generically distinct. Coria and Currie (2006) note the majority of possible adult specimens known are comparable in size to the G. carolinii holotype MUCPv-Ch1 (suggesting these G. roseae individuals were around 12.4 meters in length and 8320 kg), although not with the same exact proportions, having taller and wider neural spines, a more elongate fibula (101 centimetres compared to 98.5 centimetres) but more slender (81-89% the width as in MUCPv-Ch1) and with a differently proportioned skull that was deeper relative to its length.
Considering this, a fragmentary maxilla is coherent with the size of the MUCPv-Ch1-sized individual (MCF-PVPH-108.169). A neural arch from an axis (MCF-PVPH-108.83) and a scapular blade fragment are also the same exact size as the same elements in MUCPv-Ch1.
Moreover (contrary to popular belief), these aren't the largest remains from the bonebed - a pubic shaft (MCF-PVPH-108.145) 10% larger than that ofMUCPv-Ch1 suggests a maximum size of 13.6-13.7 meters long and 11100 kg. Some tibiae (MCF-PVPH-108.68-73) also suggest very large sizes of roughly 12.7-13.2 meters long and 8950-9880 kg.
The remains of G. roseae were discovered in a bone bed containing at least seven individuals of various growth stages. Since the bonebed's discovery and first report in 1997, researchers have speculated that this may represent gigantic theropods practicing pack-life (similar to modern carnivores like wolves and lions) and may provide clues about the behavior of this species. Paleontologist Rodolfo Coria, contrary to his published article, repeated in a press-conference the aforementioned earlier suggestions that this congregation of fossil bones may indicate that G. roseae hunted in groups and worked together to take down large prey, like the gigantic sauropod Argentinosaurus. If so, this would be the first substantive evidence of gregarious behavior by large theropods other than tyrannosaurids and Allosaurus, although whether they might have hunted in organized packs (as wolves do) or simply attacked in a mob, is unknown.
