A joint scientific team from Poland and China documented a new marine reptile that thrived approximately 250 million years ago in present-day China.
This discovery provides fresh insights into the evolutionary development of extinct reptiles’ aquatic lifestyles and reinforces the close kinship between turtles and dinosaurs along with their relatives.
Dr. Andrzej Wolniewicz from the Institute of Paleobiology at the Polish Academy of Sciences, and Hefei University of Technology in China spearheaded the research. The findings were published in the eLife journal.
The recently identified marine reptile is named Prosaurosphargis yingzishanensis. Measuring 1.5 metres in length, its physique resembled that of a colossal lizard. This reptile was distinguished by broad ribs and bony plates along its back, forming a protective armour likely utilised as both ballast and defence against predators.
“This animal was a representative of an extinct group of marine reptiles called saurosphargids (Saurosphargidae), previously known from the Middle Triassic (247-237 million years ago) in Poland and southern China. The reptile lived in a shallow, highly saline lagoon, which in the Early Triassic (about 250 million years ago) was located in what is now Hubei Province in southern China.
Wolniewicz’s team used phylogenetic methods to establish the relationship between saurosphargids and other reptile groups (phylogenetics examines the evolutionary pathways of organisms).
The analysis showed that the probable terrestrial ancestors of lizards had a well-developed skin armour. The discovery sheds new light on the evolution of the aquatic lifestyle of extinct reptiles.
“By acting as ballast, it enabled early representatives of this group to inhabit saltwater environments and move along the seabed in search of food. Some of them continued to develop their armour, however, in the species best adapted to life in water, including plesiosaurs, the armour was eventually reduced,” said the scientist.
The results of the work of the Polish-Chinese team also confirm the close relationship between archosaurs (crocodiles, dinosaurs , birds and their relatives) and turtles.
“The relationship analysis conducted by my research team, based entirely on paleontological (anatomical) data, indicates a close relationship between turtles and archosaurs. Moreover, it confirms the results of previous research, according to which archosaurs, turtles, as well as three groups of Mesozoic marine reptiles – ichthyosaurs (fish-rats), lizard-finned lizards and thalatosaurs – belonged to a huge group of reptiles called archelosaurs (Archelosauria), which achieved incredible evolutionary success, said Wolniewicz.
Header Image Credit : A. Wolniewicz