Paleontologists have described a new species of pachypleurosaur that lived during the mid-Triassic period in southwestern China.
holotype of Dianmeisaurus mutaensis From the Guanling Formation, China: (A) Skeleton seen from the back. (B) Equivalent to (A). Scale bar – 1 cm. Image credit: Hu others., doi: 10.1186/s13358-023-00292-4.
Dianmeisaurus mutaensis They lived in what is now China during the Anisian period of the mid-Triassic period, about 245 million years ago.
What is an ancient species? Pachyprourosaurus a group of primitive sauropterygian reptiles of the Triassic period.
These animals resembled aquatic lizards and had small heads, long necks, paddle-like limbs, and long, deep tails.
“Sauropterygia was the most flourishing clade of Mesozoic marine reptiles in terms of species diversity, with the iconic plesiosaurs of the Jurassic and Cretaceous, and the stem-group placodonts and eophytes of the Triassic. sauropterygia,” said Dr. Jun Liu and colleagues at the institute. Hefei University of Technology.
“Eosauropteri were traditionally divided into three groups: pachyprourosaurids, nososaurids, and pistosaurids.”
“In this traditional view, the monophyletic Pachypleurosauria is thought to constitute a sister group to the clade Eusauropterygia, which consists of Nososaurinae and Pistosaurinae.”
complete and articulated skeleton of an immature animal Dianmeisaurus mutaensis It was discovered in an abandoned quarry about 1 km northwest of Muta Village, Luxi County, Yunnan Province, China.
The skeleton was divided into two parts during collection and prepared using pneumatic tools and needles in the paleontology laboratory.
“The skeleton is embedded in dark gray micritic limestone and consists of one segment and its counterpart,” the paleontologists said.
“The specimen is well preserved and has a total length of 99.2 mm (4 inches).”
“Adjacent to the specimen are scattered limb and rib bones from other individuals, but the limited information available makes further identification difficult.”
Artist's impression of Pachypleurosaurus Umengosaurus. Image credit: Nobu Tamura / CC BY-SA 4.0.
The research team's analysis identified this new species as a sister group. Dianmeisaurus gracilis a small pachypleurosaur from the Luoping biota of the Middle Triassic.
“Dianmeisaurus mutaensis Displays several eutoroid features, including a postfrontal region that extends posteriorly to the middle of the parietal table and is excluded from the upper temporal fenestra, a stout last dorsal rib that is shorter than the first sacral rib, and two sacral vertebrae. “There is,” the researchers said.
“Additionally, a new data matrix has been compiled to reassess the interrelationships of neosauropterygians.”
“Phylogenetic analysis indicates monophyletic collapse of Eusauropterygia,” they added.
“Pistosaurinae, Magiasinosaurus and Hanosaurus These constitute a continuous sister group to the monophyletic clade that includes Pachyprosaurinae and Nososaurinae.”
“Furthermore, the monophyly of Pachyprourosauria is supported by six synapomorphies.”
“Our phylogenetic results provide further evidence for the East Tethys origin of pachypleurosaurs,” the researchers said.
“However, to test the biogeographical hypothesis, we need early Anisian pachypleurosaurs from the eastern region of Tethys.”
of findings Published in Swiss Journal of Paleontology.
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YW Hu others. 2024. A new species of Pachypleurosaurid (Reptilia: Sauropterygia) that lived in the Middle Triassic of southwestern China and its phylogenetic and biogeographical significance. Switzerland J Palaeontre 143, 1; doi: 10.1186/s13358-023-00292-4
Source: www.sci.news
