An ancient human-sized marine lizard rewrites the history of early armored marine reptiles
A new study shows that a 250-million-year-old extinct marine reptile that was covered in bony armor and swam in shallow waters in what is now southern China could rewrite the family tree of the armored marine reptiles and hint at why they first appeared. .
Newly discovered species, its name Prosaurosphargis yingzishanensisIt was identified from a partial skeleton first discovered in 2019 at the Yingzishan Quarry in China’s Hubei Province. P. yingzishanensis It belongs to the family Saurosphargidae, a group of marine, armored reptiles with broad dorsal ribs that make them look more stocky than other marine reptiles. (Sauorsphargidae is a combination of the Greek words for lizard, “sauros”, and leatherback turtle, “sphagis”.)
Researchers describe P. yingzishanensis In a study published August 8 in the journal Evolutionary Biology.
P. yingzishanensis It likely reached about 5 feet (1.5 meters) in length and was covered in osteoderms – the scales and bony plates found in many organisms reptiles, Armored dinosaurs and some Mouse tails. It was likely “one of the largest marine reptiles” inhabiting its ecosystem at the time, said the study’s lead author. Andre WollniewichThe paleontologist at Hefei University of Technology in China and the Polish Academy of Sciences told Live Science in an email.
To date, the oldest sauropods date back about 245 million years ago during the mid-20th century.Triassic period. Scientists do not know whether P. yingzishanensis Wollnowich said the dinosaurs were either a direct ancestor of these later sauropods, or a separate lineage. He added that the general body outline of the newly described species strongly suggests that the entire group may have been misclassified previously.
Related: A 240-million-year-old fossil of a salamander-like creature with “glandular teeth” was discovered in the rocks of the garden wall.
Long considered a sister family to Sauropterygia, saurosporagiids are a more diverse group of extinct marine reptiles including armored, turtle-like creatures called placodonts, and long-necked predators such as plesiosaurs.
But researchers note a large number of similarities between them P. yingzishanensis Some of the sauropterygians are similar to plesiosaurs, Wollnowich said, suggesting the two groups may be more closely related than previously thought. As a result, the study authors suggested that sauropterygoids should be reclassified as a subgroup of sauropterygae.
The researchers also believe that sauropterygians and other groups of marine reptiles, such as ichthyosaurs, which include ichthyosaurs and thalatosaurs, they may be more closely related to the clade Archelosauria–a group of living and extinct turtles and archosaurs, which includes crocodilians and birds–than previously thought.
The wide diversity of body armor in all of these groups, except for birds, also indicates that their bony plates were essential to living in shallow-water habitats, Wollnowich said. In addition to providing protection from predators, he added, this heavy coating may have enabled the marine reptiles to overcome buoyancy problems by weighing themselves down and foraging around the sea floor, where the majority of prey can be found.
The researchers hope that the area P. yingzishanensis The fossil unearthed will reveal more ancient species that could bridge the gap between groups of ancient reptiles and fill in more missing pieces in their evolutionary history.
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