TOMA VIEJA (AGENCIA CTYS).- This is the first registry of a dorado fossil. Its head, discovered in an excellent state of preservation, allowed a detailed description of the specimen and further knowledge of this predators ways during the Miocene.
Many fishermen will joke and pose, after retrieving a dorado of these specimens dimensions. However, Argentinian paleontologists rescued this fossil which s speculated to have been over 50 centimeters (19.6 inches), although the importance lies not with its size, but with the revelations of its past which made this fish so important of the fauna of South American rivers.
The investigator of the Museo de La Plata (MLP) and CONICET Alberto Luis Cione, pointed out that the ancient dorado is different from dorados presently because of the bones in its cheeks and the length of the bones that border its mouth.
The new species was baptized Salmius noriegai, acknowledging paleontologist Jorge Ignacio Noriega, who specializes in bird studies and found this 9 centimeter (3.5 inches) cranium north of Parana city in Toma Vieja.
Almost the same
Dorados today are not so different that their predecessors that inhabited in Parana and South America millions of years ago. The changes are small, subtle proportions noted in the bones, which indicated that their evolutionary process is quite slow compared to mammals, added Alberto Cione.
The dorados have maintained their food source. Given their mouth and teeth morphology there is no reason to suppose that they fed any other way, Cione detailed.
However, there are fish that have suffered major alterations during this period of time. A few years back, doctor Cione had also presented a new species: the megapiranha, and organism between the ancient pacu (South American fresh water fish) which feed on fruits and vegetables, and modern carnivorous piranhas.
Hope in new findings
We have yet to find when the dorados group originated, but paleontologist trust that Parana can provide them with more fossils in the future.
In Ciones opinión, this site is the key to understanding the evolution of both sweet and salt water fishes fauna in South America.