In 2009, a hammer blow to a spherical-shaped block of rock by the director of the Museum of Natural and Cultural History of the Atacama Desert, Osvaldo Rojas, brought to light, after 160 million years, some very fossil remains. well preserved of an unknown species.
The find was made during an expedition to the Cerritos Bayos town, located 30 kilometers southwest of Calama, in the Atacama Desert, where other extraordinary paleontological discoveries have been made, mainly of the marine fauna that inhabited the place at the end of the Jurassic period, when South America was part of the Gondwana megacontinent.
However, later analysis allowed to determine that the discovered specimen was not this time a prehistoric marine animal, but a extraordinary flying reptile of the Jurassic period, more precisely a pterosaur of the subfamily Ramphorhynchinae.
Jhonatan Alarcón, of the Paleontological Network of the University of Chile, led the study of these remains corresponding to “a left humerus, a possible dorsal vertebra, and two fragments of a wing phalanx, all conserved in three dimensions and probably belonging to a single individual “, in a study carried out together with his fellow researchers Rodrigo Otero, Sergio Soto-Acuña and Alexander Vargas, and Jennyfer Rojas and Osvaldo Rojas from the aforementioned museum in Atacama.
According to the paleontologist, the preserved pieces of this specimen -published in the magazine Acta Palaeontologica Polonica– are sufficient to determine that it is a large pterosaur for that time, probably very much like the members of a group known essentially in the Northern Hemisphere, called Rhamphorhynchinae, of which genres such as Rhamphorhynchus from Europe or Nesodactylus from Cuba.
“These pterosaurs had wing spans, tip to tip, up to 1.8 or 2 meters. Our specimen is quite large, comparable to Rhamphorhynchus, which is the largest member of this family, or perhaps the largest. “
These enigmatic winged dragons, explains Alarcón, they were characterized by “having a very elongated tail and with a peculiar termination in the shape of a rhombus. They also had low heads, long snouts and pointed teeth directed towards the front. Based on the size, especially of the humerus, which is looks very developed, and also based on comparisons with other specimens, we can say that it corresponds to an adult or a state very close to the adult stage “.
He also adds that they have been able to “rescue other bones in the area of the find, materials that have yet to be studied to determine whether or not this specimen corresponds to a new species, which is the most probable. “
A valuable piece of the Jurassic
This is the first specimen of the Rhamphorhynchinae subfamily discovered in the Southern Hemisphere, particularly in territories of the former megacontinent Gondwana.
“What exists even before this discovery are teeth found in Morocco, still assigned with doubts. Ours is the first 100% confirmed and they are also the first skeletal remains of this group. All the discoveries of the subfamily Rhamphorhynchinae come essentially from the northern hemisphere, mainly from Europe. With this, we demonstrated that the distribution of the animals in this group was broader than what was known up to now, “says Alarcón.
At the local level, on the other hand, is the first Jurassic pterosaur found so far in Chile and, therefore, the oldest representative of these winged lizards in the country.
“Jurassic pterosaurs have already been found in South America, but this is the first one discovered in Chile. In addition, it is preserved in three-dimensional form, which is rare, since pterosaurs in general are preserved with crushed bones, since they had bones very delicate and pneumatic, adapted for air travel, “he added.
Alarcón also states that this is the first pterosaur identified to be inhabited Gondwana during the Oxfordian, a specific geological age of the late Jurassic that extends from 161.2 to 155.7 million years ago.
An elongated tail ending in a rhombus-shaped point and pointed teeth directed towards the front, among the peculiar characteristics of the “ranforrincos”.
Cerritos Bayos is the specific place of this and other important paleontological finds that show how different the environment of the Atacama Desert was during the late Jurassic. This area contains a great diversity of marine deposits from this period, consisting of sandstones deposited in marine waters with coastal influence, in which abundant ammonite remains have also been found (shell mollusks relatives of octopus and squid) and fishes, which probably made up the pterosaur’s diet.
This is how last year the same team from the Paleontological Network of the U. de Chile announced the finding of plesiosaurs of the genera Muraenosaurus and Vinialesaurus, and also the first remains of pliosaurios (relatives of plesiosaurs, but with large skulls and short necks). The researchers also detail that in the place there is also a multiplicity of marine crocodiles, ichthyosaurs and giant fish, among other animals that are under investigation and that they hope to make known soon.
The identification of this pterosaur, the first animal found in this coastal ecosystem that was not strictly aquatic, also adds background on the strong link between the fauna of Gondwana -formed by territories such as South America, Antarctica, Africa, Madagascar, India and Australia- and Laurasia -mainly made up of North America, Asia and Europe.
“This finding adds evidence to the connection that occurred between the Northern and Southern hemispheres, particularly through a Caribbean passage that existed in the Jurassic, as has already been supported by marine reptiles such as the Muraenosaurus genus, found in the United Kingdom, France and Argentina, and Vinialesaurus, found in marine deposits in Cuba. “
Regarding the presence of the Rhamphorhynchinae subfamily in Gondwana, Alarcón states that the flying capacity of this animal certainly facilitated its mobility. “There are pterosaurs of this group also in Cuba, which apparently were coastal animals, so most likely they have migrated between the north and south or maybe they came once and stayed, we don’t know, but most likely is that these pterosaurs moved near the coast, since their diet was made up mainly of marine animals “, he explains.