Meraxes

Meraxes was a gigantic carcharodontosaurid dinosaur discovered in northern Patagonia, Argentina, and described in 2022. Named after a dragon from the fantasy universe of George R. R. Martin, it represents one of the most complete carcharodontosaurid skeletons known, preserving a nearly entire skull, pectoral girdle, arms, and legs. Living during the Late Cretaceous, Meraxes grew to around ten to eleven metres long and weighed over three tonnes. Intriguingly, its skeleton revealed surprisingly tiny forelimbs, showing that extreme arm reduction evolved independently alongside massive heads in both carcharodontosaurids and tyrannosaurids. The skull of Meraxes was adorned with rugged crests and knobby horns above the eyes, while its feet bore an unusually enlarged claw on the second toe, hinting at specialized hunting adaptations in South American apex carnivores.

It demonstrates that extreme forelimb reduction evolved entirely independently in both carcharodontosaurids and tyrannosaurids.

Where and when

Meraxes lived in the Late Cretaceous, from 95 to 93.9 million years ago (Cenomanian-Turonian age). Its remains come from Argentina, in the Huincul Formation.

The numbers

Length 11 m (estimates run from 10 to 11 m). Mass about 3.9 t. Hip height about 3.2 m. That is 6.2 human-lengths, or 0.94 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, hip height.

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