The newly-described saurosphargid reptile Prosaurosphargis yingzishanensis represents the earliest known occurrence of its clade.
Prosaurosphargis yingzishanensis lived in what is now South China during the Early Triassic epoch, some 247 million year ago.
“Several groups of reptiles invaded the marine realm in the aftermath of the end-Permian mass extinction, the largest extinction event in Earth’s history,” said Hefei University of Technology paleontologist Jun Liu and colleagues from Germany, Poland, and China.
“This phenomenon was likely a result of the scarcity of marine competitors and predators caused by the extinction event and high productivity in the incipient shallow marine environment.”
“Triassic marine reptiles, including the iconic Ichthyosauromorpha and Sauropterygia, as well as some other smaller and lesser known groups, achieved high taxonomic and ecological diversity rapidly after their emergence in the Late Early Triassic and played a pivotal role in the reorganization of marine food webs following the end-Permian extinction.”
“Because Mesozoic marine reptiles represent likely several independent transitions from a terrestrial to an aquatic lifestyle, they also provide an ideal system to analyze the roles of function and constraint in determining evolutionary pathways.”
Prosaurosphargis yingzishanensis was approximately 1.5 m (5 feet) in total body length and was covered by a heavy dermal armor composed of osteoderms.
The ancient species belonged to Saurosphargidae, a small group of aquatic reptiles within the large clade Sauropterygia.
“Sauropterygia was a diverse clade of Mesozoic marine reptiles that first appeared in the Late Early Triassic and its members remained important predators in marine ecosystems until their extinction at the end of the Late Cretaceous,” the paleontologists said.
“Sauropterygia is traditionally divided into two major lineages, representing two markedly different body plans: the
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