User:Diamantinasaurus/Gigaspinus

Gigaspinus is a genus of a large theropod dinosaur that lived in what is now Argentina during the Maastrichtian, approximately around 70 million years ago. The holotype specimen, MPM-Pv-98382 is known from caudal and dorsal vertebrae, an ilium, a femur, a dentary fragment and a metatarsal. The carnosaur was was found in Cerro Fortaleza Formation in 2020 and described in 2023. Unlike other Carcharodontosaurids, which went extinct during the Turonian, it is from the Maastrichtian.

Etymology
The name Gigaspinus derives from Ancien Greek 'giga', meaning 'giant' and 'spinus', which means 'spine', as it has tall neural spines, similar to those of Acrocanthosaurus and the reffered Meraxes specimen. .

Description
Gigaspinus was a large theropod with an estimated length of 13.1 m, similar or larger in size than Giganotosaurus and Tyrannosaurus. A weight of 9430 kg was based on the femur circemfurence comparable to that of Tyrannosaurus rex Scotty. The femur is 141 cm long, larger than that of any other theropod. The dentary is around 8.3% deeper than that of the holotype of Giganotosaurus, implying a skull length of around 1.75 m.

Classification
Gigaspinus is a Carcharodontosaurid theropod closely related to Giganotosaurus and Mapusaurus. The three taxa were recovered in a polytomy in Carcharodontosaurinae. However, the taxon shares several traits with the more basal Carcharodontosaurid Acrocanthosaurus. A resolution would need an analysis containing all of the proposed characters.

Provenance
The only known specimen of Gigaspinus is from the Cerro Fortelaza Formation. The tuff layer it was found in was dated to early Maastrichtian. It coexisted with the megaraptoran Orkoraptor and the giant titanosaur Puertasaurus.