Burkesuchus mallingrandensis: Jurassic-Period Crocodile Ancestor Unearthed in Chile

Thursday, August 5, 2021

Burkesuchus mallingrandensis and a group of Chilesaurus diegosuarezi. Image credit: Gabriel L. Lio / de Anatomía Comparada y Evolución de los Vertebrados (LACEV), Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia.’

Paleontologists have identified a new genus and species of small-sized mesoeucrocodylian from the fossilized remains found in the Patagonian mountains of southern Chile.

The newly-discovered crocodile species roamed Earth during the Late Jurassic period, some 148 million years ago.

The ancient creature lived alongside giant titanosaurs and other sauropod dinosaurs as well as smaller herbivorous species such as Chilesaurus diegosuarezi.

Named Burkesuchus mallingrandensis, it was a relatively small animal roughly 70 cm (27.5 inches) long.

It belongs to Mesoeucrocodylia, a group that includes all living crocodiles and their fossil relatives.

“The discovery of Burkesuchus mallingrandensis expands the meagre record of non-pelagic representatives of this clade for the Jurassic period,” said Dr. Fernando Novas, a researcher in the Laboratorio de Anatomía Comparada y Evolución de los Vertebrados (LACEV) at the Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ and CONICET, and his colleagues.

“Previously recorded members of non-pelagic Jurassic Mesoeucrocodylia are the presumably fresh-water Atoposauridae, Goniopholididae and Paralligatoridae.”

Burkesuchus mallingrandensis expands the taxonomic diversity of Jurassic crocodylomorphs,” they added.

“Nevertheless, its body size falls within the size range (i.e., less than 1 m — or 3.3 feet — in whole length) that was usual for most Triassic and Jurassic terrestrial crocodyliforms.”

The fossilized remains of Burkesuchus mallingrandensis. Image credit: Novas et al., doi: 10.1038/s41598-021-93994-z.

The fossilized remains of Burkesuchus mallingrandensis were collected from beds of the Toqui Formation, cropping out in the mountains flanked by the Maitenes and Horquetas rivers in southern Chile.

“We found part of the skull, the vertebral column and the lower extremities of the animal,” Dr. Novas said.

“This was a small crocodile no more than 70 cm long, in clear contrast to the 6-m- (20-foot) long marine crocodiles that were thriving back then in what is now the Chilean province of Neuquén, which was previously covered by the sea.”

Skeletal reconstruction of Burkesuchus mallingrandensis based on holotype and paratype specimens. Image credit: Novas et al., doi: 10.1038/s41598-021-93994-z.

“Although we didn’t find the snout of this species, its small size as well as its small and sharp teeth make us think that Burkesuchus mallingrandensis was a small carnivore that possibly fed on invertebrates such as insects or crustaceans, or small vertebrates such as fish,” said Dr. Federico Agnolin, a paleontologist in the LACEV laboratory at the Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia,’ CONICET and the Universidad Maimónides.

“What we know about Burkesuchus mallingrandensis that it didn’t have the ability to capture large prey, or tear large chunks of meat as living crocodiles do.”

Burkesuchus mallingrandensis shows how the radiation of terrestrial crocodiles occured,” Dr. Novas said.

“The shape of its body, its skull and its hind legs also shows us that it was on its way to modern crocodiles that inhabit lagoons and rivers.”

paper on the findings was published in the journal Scientific Reports.


F.E. Novas et al. 2021. New transitional fossil from late Jurassic of Chile sheds light on the origin of modern crocodiles. Sci Rep 11, 14960; doi: 10.1038/s41598-021-93994-z

Source: www.sci-news.com/