Theplesiosaur, a prehistoric marine reptile, did not reproduce by eggsbutgave birth to her live youngaccording to an American study carried out from a 78 million-year-old fossil that houses an embryo inside and published in the journalScience.
The specimen was discovered in 1987 by Charles Bonner at the Bonner Ranch, located in Kansas (USA), and has been preserved in the dinosaurs of the Natural History Museum of Los Angeles. It’s about un Polycotylus latippinus 15.4 feet long, a giant, carnivorous, four-finned reptile known as a plesiosaur, which lived during the Mesozoic era. Researchers from the museum and Marshal University, in Huntington (USA), have found in this work that it is adouble fossil of a marine reptile embryo located inside the fossil of its mother. The study corroborates that plesiosaurs gave birth to live young, and that they did not incubate eggs on land.
“The skeleton of the embryo that contains this specimen in its interior also provides us with information about the development of the body: ribs, 20 vertebrae, shoulders, hips and the bones of the fins”, explain the experts. “Although there is evidence that other groups of Mesozoic aquatic reptiles also gave birth to young (and therefore were viviparous), until now no previous evidence has been found in an order as important as that of the plesiosaurs”, The investigation points out, which is echoed by the SINC Agency.
“Scientists discovered a long time ago that the body of the plesiosaur was not suitable for leaving the water and laying eggs in a nest,” says O’Keefe. For this reason, the lack of evidence about the birth of plesiosaurs was puzzling. fossil exemplifies for the first time the way plesiosaurs were born and in this way the mystery is finally solved.
In addition, the embryo is very large compared to its mother and is much larger than could be expected when compared to other reptiles. “Many of the animals that exist today, and that dstill give birth to a single large calf, they are social and take care of their young. We wonder if the plesiosaurs would behave in the same way, and if their social behavior has been more similar to that of dolphins than that of other reptiles, “they point out.
The existence of close living relatives of plesiosaurs is currently unknown. However, this animal was very present in the waters of the oceans during the Age of Dinosaurs. It was among the most important predators of the western inland sea, a large tropical body of water that divided North America during the Cretaceous, when the waters of the Arctic Ocean and the Gulf of Mexico penetrated the continent and merged.
