More than 205 million years ago, the pterosaurs they too were in the skies of the southern hemisphere, hovering over the heads of ancient carnivorous and giant herbivorous dinosaurs, turtles and small mammalian ancestors.
A team of Argentine scientists has just extended the branches of the family tree of these flying reptiles identifying in the South American country the fossil remains belonging to two new species: Yelaphomte praderioi and Pachagnathus benitoi. The results are published in the journal Articles in Paleontology.
“Our discovery shows that in the Triassic, even at the dawn of these animals, pterosaurs lived and were already diversifying in the southern hemisphere”, explains the paleontologist to SINC Ricardo Martinezresearcher of National University of San Juan in Argentina and main author of the work.
The timing of the appearance of these distant and winged relatives of the dinosaurs. So far, the hypothesis prevailing indicates that they would have originated in the northern hemisphere. O fossils The oldest known pterosaurs were found in the Alpsin Greenland is on USA. The new research, while not contradicting it, casts doubt on this.
“These new findings provide evidence for a broader global distribution and significantly greater diversity of pterosaurs almost from the beginning of their evolutionary history,” says Martínez.
The pterosaur Pachagnathus benitoi was about 1 meter long. Its most distinguishing feature was having at least five pairs of very long teeth. / Jorge Branco
air emperors
Pterosaurs (or “winged lizards” in Greek) were the first vertebrates to develop the ability to fly. they adapted to heavens long before the appearance of birds. They were the kings of the air for over 160 million years.
These flying reptiles have lived since the end of the triassic (more than 200 million years ago) until the end of the 20th century. Cretaceous. That is, they went extinct with most dinosaurs about 66 million years ago.
They were amazing animals many: from small insectivorous species to the largest flying animals that ever existed, with life forms comparable to those of modern storks. Individuals of species such as quetzalcoatlus and Hatzegopteryx they were tall as giraffes.
Far from the misrepresentations in movies and books like Journey to the center of the Earth (1864) from Jules Verne or The lost World (1912) from Arthur Conan Doyle, pterosaurs were fast and skilled fliers; not clumsy as was thought until a few decades ago. Some lived in flocks and sported conspicuous crests on their heads.
They conquered all continents and habitats. Remains have been found on every continent, including the Antarctica. And they are full of mysteries: it is still not known how and why they learned to fly.
The first pterosaur fossil identified was a complete and exquisitely preserved skeleton found sometime between 1767 and 1784 in northern Bavaria, now Germany. the french naturalist Georges Cuvier called in 1809 Pterodactylwhich means winged finger.
Yelaphomte praderioi was a small pterosaur. It would have a conspicuous crest. / Jorge Branco.
few fossils found
In recent decades, paleontologists have been learning more about these curious animals. After the initial interest aroused in the Fantastic literaturePterosaurs were overlooked for much of the 20th century by scientists who preferred to spend their time looking for more impressive prehistoric animals, like fierce-looking dinosaurs of extraordinary size.
In addition, another factor was decisive for this “look”: the discovery of well-preserved pterosaur material is somewhat unusual. Unlike dinosaurs, these flying reptiles left behind only a few fragmentary fossils, especially as their bones were thin and hollow, fragile.
And not only that. “Pterosaurs have an important characteristic that makes scientific work very difficult: they have very little tissue bone”, says the paleontologist Ignacio A. Cerdafrom the Research Institute in Paleobiology and Geology at the National University of Río Negro.
To date, more than 100 species of pterosaurs have been identified, a tiny fraction compared to known dinosaurs.
The fossils of the two newly identified species were found in campaigns carried out in 2012 and 2014 in the Quebrada del Barro Formation, located in the province of San Juan (northwest Argentina). “The discovery of new species contributes to the knowledge of biodiversity in the evolutionary history of the Earth”, explains the paleontologist Cecilia Apaldetti.
By studying the fossil fragments, the researchers also determined that these pterosaurs inhabited and evolved in terrestrial environments rather than marine environments where other specimens have been found.
“On a global scale, the vast majority of pterosaur fossil finds have been made in areas that were once coastlines or large lagoons,” adds this researcher from the CONICET it’s from San Juan Museum of Natural Sciences. “Instead, these species lived in a continental habitat where a semi-arid climate prevailed, with vegetation concentrated mainly on riverbanks.”
new family members
Yelaphomte praderioi was a small pterosaur that must have measured no more than 25cm long from head to tail. His skull measured 7 cm. Its name derives from the allentiac – native language spoken by the Huarpe people of the province of San Juan: “Yelap” (beast) and “hometech” (air), that is, “beast of the air”–.
The specific name “praderioi” honors prairie angelmember of the team that discovered the new specimen in one of the campaigns funded by the Secretariat of Science, Technology and Innovation of the Province of San Juan.
Its most important feature is the presence of prominent crest in the premaxilla”, details Martinez. “We assume that, despite its small size, it was an adult due to the degree of ossification of the facial bone sutures, although we cannot be sure.”
Pachagnathus benitoiinstead it was a pterosaur larger: had a skull of about 35 to 40 cm and measured approximately one meter long. Its most distinguishing feature was having at least five pairs of very long teeth.
The genus name comes from the Aymara, a Native American language spoken by the Aymara people of the Andes: “Pacha” (land), referring to the interior environment in which the new species lived, and “gnathus” (jaws) in Latin. The specific name “benitoi” honors Benedict Lawsinhabitant of the small town of Balde de Leyes, who found the first fossils in the town and guided paleontologists to the site.
“Its face must have been very narrow and we don’t know for sure if it had a crest, but we suppose it did,” adds the Argentine paleontologist, known for discovering dinosaurs like eoraptor, Eodromaeus, panphagia, sanjuansaurus and Adeopapposaurusamong others.
Unlike dinosaur fossils, pterosaur remains are very scarce and fragmentary. / Ricardo Martinez
Global phenomenon 200 million years ago
In the mid-Triassic, the large landmass known as pangea started to fracture. Over time, this supercontinent was divided into Laurasia (North America and Eurasia) in the north and gondwana (South America, Africa, India, Antarctica and Australia) in the south. A new ocean, called Tethys, expanded between them.
The presence of the remains of these pterosaurs in the fossil record south of Gondwana, the scientists maintain, is evidence of how quickly the diversification and the distribution of these flying reptiles, regardless of their origin.
“This shows that pterosaurs were a global phenomenon from the beginning,” says the paleontologist brian andres from the University of Sheffield, England, who supervised the research.
Between about 202 and 210 million years ago, Yelaphomte praderioi and Pachagnathus benitoi coexisted with a varied fauna: carnivorous dinosaurs such as Lucianovenator bonoi and large herbivores like raw intelligenceboth also discovered by Martínez and Apaldetti.
The area also ran through cynodonts or small ancestors of the mammals; turtles (Waluchelys cavitesta); and giant herbivorous sphenodonts (sphenotitan laws), ancestors of crocodilians.
“We are just two paleontologists in San Juan to study such a site,” he says. apaldettiwho went from examining meter-long femurs of herbivorous dinosaurs to analyzing these more fragile, palm-sized fossils.
The hope of finding more remains in the field, the struggle to obtain funding to carry out CT scans in England, the complications brought about by the covid-19 pandemic and the appearance of other fossils made the publication times of this research to be lengthened. .
“It’s a unique place”, says this Argentine paleontologist. “It will continue to amaze for many years to come.”
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