Wed. Jul 17th, 2024

An exciting discovery in Argentina has shed light on the evolutionary history of theropod dinosaurs. Paleontologists have identified a new genus and species, named Diuqin lechiguanae, which fills a significant gap in the fossil record of unenlagiine dinosaurs.

Diuqin lechiguanae lived during the Santonian age of the Cretaceous period, roughly 84 to 86 million years ago. This long-snouted predator belonged to the Unenlagiinae subfamily, part of the Dromaeosauridae family within the Paraves clade, which includes birds and their closest relatives.

Unenlagiines are primarily known from Argentina, where the most complete skeletons have been found. However, potential unenlagiine fossils have also been discovered in Brazil, Chile, Colombia, Antarctica, and even Madagascar.

These dinosaurs are crucial for understanding the origins of birds due to their close evolutionary relationship with birds. Unfortunately, most unenlagiine species are known only from fragmentary remains.

Diuqin lechiguanae is a valuable addition as it provides a more complete picture. This fragmentary but associated postcranial skeleton was recovered from the Bajo de la Carpa Formation in Patagonia, Argentina.

This discovery is particularly significant because it’s the first unenlagiine dinosaur identified from this formation. The Bajo de la Carpa Formation boasts a diverse collection of fossils, including snakes, lizards, turtles, and even early birds.

Diuqin lechiguanae bridges a critical 15-million-year gap (possibly even longer) in the unenlagiine fossil record of South America.

The dinosaur’s unique anatomical features, including a distinctive structure on its vertebrae and a humerus with characteristics intermediate between other unenlagiine species, further support its classification as a new species.

Interestingly, the humerus also bears tooth marks, suggesting it was scavenged by another animal, possibly a crocodyliform, mammal, or even another theropod dinosaur.

Sources:
Published 14 June 2024 in the journal BMC Ecology and Evolution; Diuqin lechiguanae gen. et sp. nov., a new unenlagiine (Theropoda: Paraves) from the Bajo de la Carpa Formation (Neuquén Group, Upper Cretaceous) of Neuquén Province, Patagonia, Argentina;
doi: 10.1186/s12862-024-02247-w

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