In a new study printed within the journal PLoS ONE, paleontologists analyzed the fossilized stays of the alvarezsaurid dinosaur Bonapartenykus from the Allen Formation of Patagonia. Their outcomes shed new mild on the physique plan of Bonapartenykus and different members of the alvarezsaurid dinosaur group Patagonykinae.
Life reconstruction of a person of Bonapartenykus from the locality of Salitral Ojo de Agua of the Allen Formation, Patagonia, Argentina. Picture credit score: Abel G. Montes.
Bonapartenykus lived in what’s now Patagonia, Argentina, roughly 70 million years in the past (Cretaceous interval).
First described in 2012, this dinosaur belongs to one of the vital mysterious teams of dinosaurs, referred to as the Alvarezsauridae.
With one other Patagonian genus, Patagonykus, Bonapartenykus kinds a small alvarezsaurid clade, the Patagonykinae.
“Alvarezsauria is a bunch of later-diverging coelurosaurian theropod dinosaurs of medium to small measurement, whose fossil document spans from the Late Jurassic to the Late Cretaceous,” mentioned Universidad Nacional de Río Negro paleontologist Jorge Gustavo Meso and colleagues.
“The distribution of this clade was doubtless initially Laurasian since its earliest recognized members are at the moment restricted to the Oxfordian (Late Jurassic) of China.”
“The Early Cretaceous fossil document of Alvarezsauria was additionally restricted to the Asian continent, which now consists of as much as three species.”
“By the Late Cretaceous, Alvarezsauria was extremely diversified and globally distributed, with plentiful Laurasian data from what’s now Asia, Europe, and North America in addition to the primary Gondwanan data represented by discoveries from South America.”
“Patagonykinae is the one named South American clade of alvarezsaurids that clusters Patagonykus and Bonapartenykus.”
Of their new research, Dr. Gustavo Meso and co-authors examined numerous alvarezsaurid fossils from the Salitral Ojo de Agua locality of the Patagonian Allen Formation.
“Though these specimens have been collected at totally different occasions with out exact unique provenance data, we gathered X-ray diffraction information of the related sediments that now suggests that each one of those specimens come from the identical web site and stratigraphic degree because the holotype of the alvarezsaurid Bonapartenykus ultimus,” the paleontologists mentioned.
“Primarily based on this new provenance data and the morphological similarity of the thought of specimens, we tentatively refer them to the genus Bonapartenykus.”
In line with the authors, the newly-described specimens make clear the physique plan of Patagonykinae by allowing a extra full reconstruction of their neck, pectoral girdle, hindlimb, and tail.
“Whereas our outcomes favor a monospecific alvarezsaurid assemblage for the second, future analysis and quarrying efforts on the Salitral Ojo de Agua locality might unearth proof that may additional take a look at our present interpretation,” they mentioned.
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J.G. Meso et al. 2025. New data on Bonapartenykus (Alvarezsauridae: Theropoda) from the Allen Formation (center Campanian-lower Maastrichtian) of Río Negro Province, Patagonia, Argentina clarifies the Patagonykinae physique plan. PLoS ONE 20 (1): e0308366; doi: 10.1371/journal.pone.0308366
