Cronopio (mammal)
Reconstruction
- Argentina, Candeleros lineup
- Cronopio dentiacutus Rougier, Apesteguia & Gaetano, 2011
Cronopio dentiacutus is a mouse large mammal that lived during the Cretaceous period about 100 million years ago in South America. The site of the first discovery is located in Patagonia, Argentina. Cronopio belongs to the so-called Dryolestoiden, an extinct group of animals, descended from the present-day marsupials and the higher mammals. Cronopio is named after the fictional characters from the short story collection Historias de cronopios y de famas the Argentine writer Julio Cortázar. The second part of the name is dentiacutus Latin origin and refers to the pointed canines (Latin dens, " tooth", and Latin acutus " sharp, pointed ").
Features
Cronopio dentiacutus was (without the tail ) is approximately 10 to 12 cm long. The skull of the holotype is about 27 mm long. He has a long, narrow snout, large eye sockets, a specialized jaw muscles and dagger -like canine teeth, which occur as in any other mammal of the Mesozoic. Its length is 5 mm. Since there were no skull finds this group of Dryolestoiden, the relationships could not be determined in detail. Thanks to this first skull findings, however, it is clear that cronopio still had a number of primitive features. But his middle ear is similar in design to today's mammals.
The first description of cronopio comprises three specimens: the holotype MPCA PV 454, an incomplete skull, where the skull roof, the lower face ( basicranium ) and the shed leg missing, and the associated specimens MPCA PV 450, an incomplete left mandible with damaged teeth, including posterior premolars and molars damaged, and MPCA PV 453, an incomplete skull with a relatively complete right mandible in which the incisors and canines are missing. Since MPCA PV 454 and 453 complement each other well, could of cronopio a skull to be reconstructed, in which only a few bones and teeth are missing: the lower incisors and canines, the Septomaxilla - a bone in the front reptiles jaw, which in mammals except the monotremes no longer receive independent - the head crest and part of the cranial vault. MPCA is the abbreviation for the Museo Provincial de Cipolletti Carlos Ameghino, located in Cipolletti in the Argentine province of Río Negro.
System
Cladogram, which suggest the discoverer. The node before Paurodontidae and Meridiolestida is not yet named.
Henkelotherium
Dryolestes
Comotherium
Amblotherium
Laolestes
Groebertherium
Foxraptor
Paurodon
Drescheratherium
Leonardus
Cronopio
Reigitherium
Peligrotherium
Mesungulatum
Coloniatherium
Diet and lifestyle
Rougier suspected because of the molars found that cronopio mainly fed on insects, larvae, invertebrates, and possibly smaller lizards that were also discovered at the site. In contrast, the function of the long canines is difficult to interpret, since such long canines do not occur at comparable, live animals. The skull of cronopio was more easily built and not designed for large loads. Cronopio could not use his saber teeth to subdue prey, because the risk of injury would have been too large.
At the time of cronopio the archaeological site was a flood plain, inhabited by large dinosaurs, crocodiles, turtles, and snakes Sphenodontien. Little is known about the flora, but came before some large conifers. It came regularly to flooding, possibly brought about the death of cronopios.
Christian de Muizon indicated the large eye sockets as an indication that cronopio may have been nocturnal.
Discovery
In 2002, researchers discovered in the archaeological site " La Buitrera " the Candeleros lineup in the province of Río Negro in Argentina a first almost completely enclosed by rock skull. In 2005, she gave the Fund an expert who took three years to expose the fossil. Published in 2011 Guillermo W. Rougier, Sebastián Apesteguia and Leandro C. Gaetano their report on their findings. It is well-preserved skull and jaw. Usually can be found from the early mammals only teeth and possibly bone fragments. Well-preserved skull, however, are extremely rare. The discovery of Rougiers team also includes, for the South American mammals without a gap remains of around 60 million years ago. Before that, from the time of the dinosaurs, only the skull of Vincelestes neuquenianus, an animal the size of a small possums that lived 130 million years ago, known.
Trivia
In the press the similarity of cronopio with the " saber-toothed squirrel " Scrat was stressed from the animated film Ice Age. Rougier itself shows poking fun at the resemblance. While watching the film, he had wondered how the filmmakers so ridiculous animal could only have come up that have no relation to reality. And then his team would find later, such an animal.