A brand new stegosaurian genus and species from the Center Jurassic epoch has been recognized from the postcranial stays discovered within the Center Atlas Mountains south of Fès, Morocco.

An artist’s impression of Thyreosaurus atlasicus. Picture credit score: Sci.Information.

Thyreosaurus atlasicus lived in northern Africa in the course of the Center Jurassic epoch, roughly 165 million years in the past.

The species is carefully associated to Dacentrurus, a member of the clade Dacentrurinae throughout the thyreophoran dinosaur household Stegosauridae.

“Thyreophora is a various clade of herbivorous ornithischian dinosaurs composed of stegosaurs, ankylosaurs, and basal varieties,” mentioned Dr. Mostafa Oukassou from the Hassan II College of Casablanca and colleagues.

“Thyreophorans have an intensive fossil report, spanning from the Decrease Jurassic to the Higher Cretaceous, which is finest recognized from well-preserved specimens in Laurasia.”

“In distinction, fossil stays are poorly recognized and largely partial in Gondwana,” they added.

“In Africa, thyreophorans might have been current because the Early-Center Jurassic.”

“Stegosaurian physique fossils are documented within the Center Jurassic of Morocco, the Higher Jurassic of Tanzania and the Decrease Cretaceous of South Africa.”

“African ankylosaurs are represented solely by Spicomellus afer from the Center Jurassic of Morocco.”

The disarticulated partial skeleton of Thyreosaurus atlasicus was discovered within the grey marls of the El Mers III Formation within the northern Boulahfa locality, close to Boulemane, Center Atlas of Morocco.

“In 2021, throughout a geological mapping mission south of Boulemane, we found a brand new website wealthy in dinosaur stays within the El Mers III Formation,” the paleontologists mentioned.

“This website, named Boulahfa North, is positioned north of the Boulahfa quarry.”

“The fabric was collected over a number of consecutive area journeys, and consists of a partial postcranial skeleton of a stegosaur that features dorsal vertebrae and ribs, a limb bone and dermal armor.”

In accordance with the group, Thyreosaurus atlasicus had an asymetric weird dermal armor, distinctive amongst stegosaurs.

“The dermal armor of Thyreosaurus atlasicus consists of thick — as much as 4 cm (1.6 inches) — subovate to subrectangular-shaped osteoderms,” the researchers mentioned.

“The asymmetrical texture of their sides, one roughly ornamented with small pits and fiber bundles, the opposite with a well-marked cross-hatched sample, is clearly completely different from that noticed up to now in different stegosaurs, and ankylosaurs.”

“The bone histology of those osteoderms is harking back to that of stegosaurian tail spines.”

“It’s interpreted that these osteoderms had been organized in a recumbent place over the physique of the animal, as a substitute of an erect place.”

Thyreosaurus atlasicus had an estimated physique size of over 6 m (19.7 toes).

“Axial characters point out that the specimen belongs to a medium to large-sized stegosaur,” the scientists mentioned.

“The holotype corresponds to an grownup particular person who didn’t attain its most physique dimension.”

The invention of Thyreosaurus atlasicus is necessary in understanding the evolutionary historical past of stegosaurs and different thyreophoran dinosaurs.

“The current discoveries of Adratiklit and Thyreosaurus atlasicus present perception into the early evolution of stegosaurs within the Center Jurassic of Africa,” the authors concluded.

The findings seem within the journal Gondwana Analysis.

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Omar Zafaty et al. 2024. A brand new stegosaurian dinosaur (Ornithischia: Thyreophora) with a exceptional dermal armour from the Center Jurassic of North Africa. Gondwana Analysis 131: 344-362; doi: 10.1016/j.gr.2024.03.009