#sidersaura

The first dinosaur of 2024.

Impression of Sidersaura marae

(Partial skull of Sidersaura marae [scale bar = 5 cm], from Lerzo et al., 2024)

Meaning of name: Sidersaura = star [in Latin, referencing the star-like shape of the bony projections under its tail vertebrae] lizard [in Greek]; marae = for Mara Ripoll [director and technician at the Ernesto Bachmann Paleontological Museum]

Age: Late Cretaceous (Cenomanian–Turonian)

Where found: Huincul Formation, Neuquén, Argentina

How much is known: Partial skeletons of two individuals, together including parts of the skull, several vertebrae, and limb bones. A partial fibula (lower leg bone) and a back vertebra representing two other individuals are also known.

Notes: Sidersaura was a rebbachisaurid, a group of sauropods best known for including the bizarre Nigersaurus from the Early Cretaceous of Niger. Sidersaura is one of the youngest rebbachisaurids yet found, as they are not known to have survived past the early Late Cretaceous. Being represented by relatively complete remains, it provides valuable information on rebbachisaurid anatomy, such as confirming the presence of similarities between the tail vertebrae of rebbachisaurids and those of the distantly related titanosaurian sauropods, which has led to members of the two groups being occasionally confused for one another in the past.