#chakisaurus

[totaldino]

Chakisaurus

Chakisaurus is a medium-sized elasmarian ornithopod dinosaur known from multiple partial skeletons belonging to individuals of different ages. Elasmaria is a diverse group of basal ornithopods known from the southern hemisphere. Chakisaurus is notable for having a downward curve in the base of its tail, a trait previously only seen in titanosaurs.

[the-dragon-girl-27]

flocking drawings!!

Young Altispinax preparing to do a mating display

Thyreosaurus slaying a Theropod

Ornithoprion just swimming round

Mama Mapusaurus bringin home a Chakisaurus carcass for her daughter

[new-dinosaurs]

Chakisaurus nekul Nogueira et al., 2024 (new genus and species)

(Tail vertebrae of Chakisaurus nekul [scale bar = 3 cm], from Nogueira et al., 2024)

Meaning of name: Chakisaurus = elder guanaco [in Tehuelche] lizard [in Greek]; nekul = swift [in Mapudungun]

Age: Late Cretaceous (Cenomanian–Turonian)

Where found: Huincul Formation, Río Negro, Argentina

How much is known: Partial skeletons of several individuals together representing much of the vertebral column and multiple limb bones. An isolated partial ulna (forearm bone) and a neck vertebra are also known.

Notes: Chakisaurus was an ornithopod, a group of plant-eating dinosaurs that includes the duck-billed hadrosaurids. However, it was only distantly related to the hadrosaurids, instead being a member of Elasmaria, a diverse group of small to medium-sized ornithopods from the Southern Hemisphere.

Chakisaurus had unusual features of its tail vertebrae indicating that the base of its tail may have been typically held with a downward curve, instead of horizontally as is the norm for most other dinosaurs. Among dinosaurs, this type of tail configuration had previously only been reported in some types of titanosaurian sauropods. Additionally, the main muscles that pull the hindlimbs backward (which are attached to the tail in most dinosaurs and other reptiles) appear to have been very well developed in Chakisaurus, which may suggest that it was a powerful sprinter.

Fossils of both juvenile and older individuals of Chakisaurus have been found, allowing study of its growth. Based on microscopic examination of its bone structure, the largest known specimen of Chakisaurus had reached sexual maturity when it died, but had not finished growing, a pattern commonly seen in Mesozoic dinosaurs.

Reference: Nogueira, R.A., S. Rozadilla, F.L. Agnolín, J.A.G. Marsà, M.J. Motta, and F.E. Novas. 2024. A new ornithopod from the Upper Cretaceous (Huincul Formation) of northwestern Patagonia, Argentina. Implications on elasmarian postcranial anatomy. Cretaceous Research advance online publication. doi: 10.1016/j.cretres.2024.105874

[fishsfailureson]

The recently discovered elasmarian Chakisaurus