New Triassic Marine Reptile Spaturidentatus breviceps Discovered in China

A new genus and species of sauropterygian marine reptile that lived approximately 245 million years ago has been identified from a nearly complete skeleton discovered in southwestern China.

Sauropterygians were a highly successful group of marine reptiles that evolved from terrestrial ancestors shortly after the end-Permian mass extinction.

These paddling reptiles dominated shallow coastal waters during the Triassic Period and were widely distributed along the margins of the ancient Tethys Sea.

“Sauropterygians are a group of diapsid marine reptiles that were widely distributed throughout the Mesozoic oceans,” said researchers from Hefei University of Technology and their colleagues.

“They flourished particularly during the Triassic, inhabiting shallow-water environments primarily along the eastern and western coasts of the Tethys.”

Sauropterygians traditionally include four major groups: placodonts, pachypleurosaurs, nothosaurs, and plesiosaurs.

In recent years, numerous sauropterygian fossils have been discovered in southwestern China. Genera such as Atopodentatus, which possessed unusual hammer-shaped jaws, as well as species with different forms of dorsal armor, have challenged traditional views about the origin, dispersal, and evolution of these marine reptiles.

Spaturidentatus breviceps

The newly described species lived approximately 245 million years ago during the Anisian age of the Triassic Period, when marine ecosystems were still recovering from the devastating end-Permian extinction.

Named Spaturidentatus breviceps, the animal measured approximately 2.7 meters (9 feet) in total length.

Its jaws were lined with small, spoon-shaped teeth. However, the reptile had an unusually compact skull that accounted for only about 5% of its total body length.

The nearly complete and articulated skeleton was recovered from the upper part of the Guanling Formation, a Triassic rock unit exposed along the border between China’s Yunnan and Guizhou provinces.

The fossil, cataloged as GMG10, is housed at the Guizhou Geological Museum.

“The specimen is preserved in lateral view, with the torso exposed on the ventral surface,” the paleontologists said.

“The forelimbs and hind limbs are well preserved, except for their distal parts.”

“The rostrum is short, the atlas is not discernible, and at least 12 cervical vertebrae are preserved with well-developed cervical ribs.”

Preliminary comparisons suggest that Spaturidentatus breviceps may be closely related to some of the most primitive sauropterygians, including the shell-crushing placodonts and the taxonomically uncertain genus Atopodentatus.

“The Anisian species Spaturidentatus breviceps, from the Yunnan-Guizhou border region of southwestern China, provides important new material for phylogenetic studies of early sauropterygian evolution,” the researchers concluded.

The team’s paper was published in the journal Geological Review.

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Yang et al. 2026. A new sauropterygian (Reptilia: Sauropterygia), Spaturidentatus breviceps gen. et sp. nov., from the Middle Triassic of the Yunnan-Guizhou border region. Geological Review 72 (4): 1280–1285; doi: 10.16509/j.georeview.2025.11.052.