Scientists find an almost complete 70-Myr-old skeleton of crocodile

The species Barrosasuchus neuquenianus was found in Neuquén by CONICET researcher Rodolfo Coria.

A group of Argentine and foreign researchers led by Rodolfo Coria, paleontologist of the National Scientific and Technical Research Council (CONICET), presented the skeleton of Barrosasuchus neuquenianus, a crocodile that belongs to the family of peirosaurid, which used to be about two meters long and lived 70 Myr ago in Sierra Barrosa, 30 km from Plaza Huincul, in Neuquén. Although these type of crocodiles came to be known more 60 years ago, this finding is particular because the skeleton is almost complete –the only piece that is missing is the tail-. The study was recently published in Cretaceous Research.

 “Barrosasuchus is a deluge of peirosaurid information” said Coria when he realized that the finding included the skull, the postcranium, jaws, legs, hands, ribs and vertebrae of periosaurid crocodile. “It’s complete, the only missing piece is the tail”, the scientist indicates. “It is not common to find complete and well-preserved specimens, specially crocodiles.”

The first peirosaurid was found sixty years ago in Peirópolis, in the center of Brazil. Then the scientists at that time noticed that that specimen represented a family of crocodiles that was different from others so the experts called it peirosaurid for Peirosaurus was the first genus recognized in the family. These crocodiles, which inhabited the Upper Cretaceous, were abundant and frequent in all South America, specially in Patagonia but most specimens had been found in a fragmentary way. “Until now, pieces of jaw, of snout, and incomplete skulls without jaw had been found. Although it is frequent to find the remains of these animals -which sometimes allowed scientists to propose new species-  it is exceptional and unique to find the complete skeleton, like in the case of the Barrosasuchus”, comments the researcher.

What triggered the finding of this crocodile took place in 2001, during one joint expedition to Sierra Barrosa, located 30 km away from Plaza Huincul.  The research team included experts from the Museo Carmen Funes de Plaza Huincul, Neuquén and the Royal Tyrrell Museum of Paleontology of Canada. The scientists found several pieces to study during the following years. “We found carnivorous dinosaur bones, herbivores, mammals but it took us a lot of time to record everything we had found in those expeditions at the beginning of this century. For this reason, we can now study the complete specimen of the crocodile and introduce the Barrosasuchus” Coria explains.

The etimology of the Barrosasuchus neuquenianus, as this finding was called, comes from “Barrosa”, in allusion to Sierra Barrosa, where the specimen was found, and “souchos”, in Greek, which refers to the Egyptian divinity that had a crocodile’s head and is commonly used in scientific names for crocodile species. The name of the species “neuquenianus” was chosen for the province of Neuquén.

For Coria, “this specimen allows us to value the wonders of nature and the luck of having the fossilization process to witness and observe the remains of the forms of life that extinguished 70 Myr ago in a great state of conservation.”

The most praised piece was the postcranium: “We only parts that were known were skulls or fragments of cranium. Barrosasuchus helps us to know much more about the anatomy of the rest of these animals –the proportion of the legs, the type of anatomy of hands and feet, or to know if the ribs were straight or curved. All these provides information that was not available to scientists for many years, at least sixty years, when the first peirosaurid was described in Brazil.”

Research team:

Dr. Rodolfo A. Coria (Subsecretaría de Cultura de Neuquén, CONICET, UNRN, and Museo Municipal Carmen Funes de Plaza Huincul)

Dr. Francisco Ortega (Grupo de Biología Evolutiva, Facultad de Ciencias, UNED, Madrid, España)

Dra. Andrea B. Arcucci (Universidad Nacional de San Luis, Área de Zoología, IMIBIO-CONICET, San Luis)

Dr. Philip J. Currie (University of Alberta, Edmonton, Canada).

By Cintia Kemelmajer