New South African Dinosaur Nyana rooiwalensis: Juvenile Already Weighed About 400 Kilograms, From a Near-Complete Late Triassic Skull
A team led by Atashni Moopen of South Africa's University of the Witwatersrand has described a new dinosaur, Nyana rooiwalensis, in Royal Society Open Science (DOI: 10.1098/rsos.261002). The animal lived more than 200 million years ago in what is now South Africa and was identified from a near-complete skull and several other fossilized bones. It belonged to the sauropodomorphs, the group that eventually gave rise to long-necked giants such as Brachiosaurus and Diplodocus.
The fossil was collected in 2018 near Qhemegha village in the Eastern Cape, and the holotype, specimen BP/1/8468, preserves a skull measuring 21.3 centimeters. The researchers used powerful X-rays to create a detailed 3D model of the skull and compared its features with those of other sauropodomorphs to place Nyana on the dinosaur family tree.
Thin slices of limb bones examined under a microscope showed the animal was still growing rapidly when it died, and was at least in its third year of growth. By measuring the circumference of its thigh bone and comparing it with growth curves from related dinosaurs, the team estimated it already weighed about 400 kilograms, or 880 pounds, and probably walked on two legs. Extrapolation of the growth curves suggests adults may have reached multi-tonne body masses, the authors wrote.
The remains come from the lower Elliot Formation, of Norian to Rhaetian age in the Late Triassic. The specimen is the first almost complete, articulated dinosaur skull from the South African Late Triassic, and fossilized skulls of sauropodomorphs of this age are relatively rare in southern Africa. Analyses recover Nyana as a close relative of Sarahsaurus from North America or of the South African Ngwevu, providing new data on how these early dinosaurs evolved and spread.
Source: Royal Society Open Science
Published by GSM · USA (original Chinese edition)
Photo: 图：新种恐龙 Nyana rooiwalensis 的正模头骨化石（标本 BP/1/8468）的三个视图。来源：A. Moopen 等，《皇家学会开放科学》，CC BY 4.0。 / Photo: Three views of the holotype skull fossil of the new dinosaur Nyana rooiwalensis (specimen BP/1/8468). Source: A. Moopen et al., Royal Society Open Science, CC BY 4.0.
