By Valerio Rasi–
A new mammal species, Cronopio dentiacutus, has been discovered and analyzed in South America by Professor Guillermo W. Rougier of the University of Louisville. Cronopio comes from the work of Argentinian writer Julio Cortázar, who is one of the Dr.Rougier’s favorite writers. The widow of this famous writer just recently contacted Professor Rougier to express her excitement over this dedication.
Dr. Rougier commented that this animal would look like “Scrat” from the “Ice Age” cartoon. There are no scientific links between the species, but the majority of the population might better understand this comparison. This research has been a major finding for those who study biology because the extinct animal has never been found in such detail. The skull and jaw were very well preserved. This new discovery was published in “Nature” on Nov 3rd.
“It is a great credit for the University of Louisville to be published in ‘Nature,’” said Phil Ardery, a post-baccalaureate student with a passion in biology, “and it is a very high honor for any professor.” The importance behind this discovery is also “to have extended the South American stratigraphic record of the group about 30 million years further back.” From this, questions have been raised on what path this animal took in evolution and how it moved to South America.
The species comes from the superorder Dryolestoidea, which is well known and observed in North America and Africa, but never really documented in South America. Two theories seem to be the most probable on its radiation. The first says that the animal, during the Cretaceous, crossed a temporary bridge to enter South America from the north. The North American ancestor would have lived in a similar fauna and had many similar traits.
The second theory is related to a connection to Africa. The southern hemisphere was actually connected between Africa and South America as part of the supercontinent Gondwana. This discovery might not address all the answers necessary to fully understand the history of mammals in South America, but it is now relevant for the understanding of the evolution of the species and a possible link between two geographic locations.
Cronopio was found in 2006, but was fully excavated just recently. The site was so imbedded in rock that the paleontologist had to be very careful and meticulous during the excavation. Also, “it took a long time to describe every little part and have the description perfectly ready,” said Dr. Rougier’s wife, Dr. Cynthia Corbitt Ph. D, professor in the biology department. “Anything that can shed light on our interconnectedness to both the biological past and to other species amuses me in biology,” student Ardery said.
Photo courtesy Nature Magazine