It has been baptized as Wunyelfia maulensis (“lizard of the morning star of the Maule”, which refers to the Wünelfe of the Mapuche People , the nine-pointed star , it is a tribute to the Mapuche worldview by the research team) and is It is about a member of Aristonectinae, a group of plesiosaurs in the Elasmosauridae family that lived approximately 67 million years ago during the Maastrichtian stage of the Cretaceous period.
It is the second representative of this group known to date in the southeastern Pacific during the late Maastrichtian stage.
“The Aristonectinae were a monophyletic lineage of elasmosaurid plesiosaurs morphologically and ecologically different from other typically long-necked elasmosaurids,” explain paleontologists Rodrigo Otero and Sergio Soto-Acuña from the University of Chile who signed the study published in the journal Cretaceous Research.
“The former were characterized by the acquisition of enlarged skulls, a greater number of teeth, as well as shortened and thickened necks, which spread mainly throughout the Weddell province during the late Cretaceous.”
Its closest relative is Aristonectes parvidens , found in the 1940s in Argentine Patagonia , of which only part of the skull, neck, and fragments of a fin and tail are known.
“They are frequent in the Maastrichtian of the southern hemisphere, with occurrences in Argentine Patagonia, central and southern Chile, New Zealand and Antarctica. The growing body of evidence currently shows that among the southern elasmosaurid plesiosaurs, at least one monophyletic lineage ( Aristonectinae) reached a provincial diversity with endemic forms in Antarctica, New Zealand and southern South America during the Upper Cretaceous ”, clarify the experts.
The near-adult partial postcranial skeleton of Wunyelfia maulensis was recovered from the upper Maastrichtian levels of the Quiriquina Formation in central Chile.
“The skeleton studied was recovered from exposed strata in the town of Mariscadero, south of Pelluhue, 320 km southwest of Santiago,” the researchers comment. “The sample was found 20 cm above a second partial postcranial skeleton of an indeterminate elasmosaurid.”
“Its small, almost adult size differs from the larger contemporaneous forms previously described in South America, particularly Aristonectes parvidens and Aristonectes quiriquinensis, with estimated lengths of more than 10 meters,” they noted.
Aristonectins appear to have exploited a unique unrecorded trophic niche among other plesiosaurs.
“The presence of Aristonectes and Wunyelfia during the late Maastrichtian of central Chile can be correlated with a highly productive ecosystem capable of supporting taxonomic diversity within this distinctive ecomorphotype,” the scientists said. “Further studies on this new taxon and other early aristonectins will be key to understanding the origin and evolution of this unique clade of elasmosaurids.”
As a curiosity, in Chile fossils are property of the state and any excavation must have the proper authorization. In this case, the bone material was excavated in the early 1990s by amateurs and without proper techniques for fossil extraction, so much information has been lost along the way.
Referencia: R.A. Otero & S. Soto-Acuña. Wunyelfia maulensis gen. et sp. nov., a new basal aristonectine (Plesiosauria, Elasmosauridae) from the Upper Cretaceous of central Chile. Cretaceous Research 118: 104651; doi: 10.1016/j.cretres.2020.104651
