A brand new genus and species of ankylosaur has been recognized from an nearly full skeleton present in Chilean Patagonia.
An artist’s reconstruction of Stegouros elengassen. Image credit score: Luis Pérez López.
The new dinosaur species lived in what’s now Chile throughout the Upper Cretaceous epoch, some 74 million years in the past.
Named Stegouros elengassen, it was between 1.8 and a couple of m (5.9-6.6 ft) lengthy together with its quick tail.
The historical creature was a sort of ankylosaur, a bunch of herbivorous armored dinosaurs.
“Armored dinosaurs are well known for their evolution of specialized tail weapons — paired tail spikes in stegosaurs and heavy tail clubs in advanced ankylosaurs,” stated Universidad de Chile’s Dr. Sergio Soto-Acuña and his colleagues.
“Armored dinosaurs from southern Gondwana are rare and enigmatic, but probably include the earliest branches of Ankylosauria.”
Stegouros elengassen advanced a big tail weapon not like any dinosaur: a flat, frond-like construction shaped by seven pairs of osteoderms encasing the distal half of the tail.
“The weapon that Stegouros elengassen possesses in the tail is different from both that of stegosaurs (composed of pairs of spikes), and that of advanced ankylosaurs (similar to a club),” the paleontologists stated.
“It looks like a macuahuitl, the weapon of the ancient Aztecs.”
Skeletal anatomy of the Stegouros elengassen holotype: (a) preserved components of the skeleton; the mandible is reversed, and the place of osteoderms in grey shade is unsure; (b, c) dorsal (b) and proper lateral (c) views of the rostral portion of the premaxilla; (d) caudal view of the occipital advanced; (e, f) digital reconstruction of cheek tooth, labial (e) and lingual (f) views; (g) anterior view of the mid dorsal vertebra; (h, i) lateral (h) and anterior (i) views of the left humerus; (j) lateral view of the left ulna; (ok) dorsal view of the partial proper hand; (l) dorsal view of the pelvis; (m) anterior view of the proper femur; (n) anterior view of the left tibia and fibula; (o) articulated proper foot (ventral view); (p) articulated tail with caudal weapon of paired osteoderms. Scale bars – 50 cm (a), 1 cm (b, c, g-k and m-o), 5 mm (e and f) and 10 cm (l and p). Image credit score: Soto-Acuña et al., doi: 10.1038/s41586-021-04147-1.
The principally full skeleton of Stegouros elengassen was found within the decrease part of the Dorotea Formation in Río de las Chinas Valley, Chile’s Magallanes area, a area that’s biogeographically associated to West Antarctica.
The researchers discovered that the brand new species was intently associated to 2 ankylosaur species, Kunbarrasaurus ieversi from Australia and Antarctopelta oliveroi from Antarctica, forming a clade of Gondwanan ankylosaurs that cut up earliest from all different ankylosaurs.
“The large osteoderms and specialized tail vertebrae in Antarctopelta suggest that it had a tail weapon similar to Stegouros,” they stated.
“We propose a new clade, the Parankylosauria, to include the first ancestor of Stegouros — but not Ankylosaurus — and all descendants of that ancestor.”
A paper describing the invention was revealed within the journal Nature.
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S. Soto-Acuña et al. 2021. Bizarre tail weaponry in a transitional ankylosaur from subantarctic Chile. Nature 600, 259-263; doi: 10.1038/s41586-021-04147-1