A new genus and species of sauropterygian reptile that lived during the Triassic period, some 245 million years ago, has been identified from a nearly complete skeleton found in China.
The holotype of Spatulidentatus breviceps. Image credit: Yang et al., doi: 10.16509/j.georeview.2025.11.052.
Sauropterygians were a highly successful lineage of paddling marine reptiles that developed from terrestrial ancestors soon after the end-Permian extinction.
These creatures dominated shallow coastal seas during the Triassic, spreading along the margins of the ancient Tethys Ocean.
“Sauropterygians (Sauropterygia) are a group of diapsid marine reptiles widely distributed in Mesozoic oceans,” said Mei Yang, a doctoral student at the Hefei University of Technology, and her colleagues.
“Sauropterygians flourished most during the Triassic, mainly inhabiting shallow-water environments along the eastern and western Tethys coasts.”
“Traditionally, Sauropterygia comprised four major groups: Placodontia, Nothosauroidea, Pistosauroidea, and Plesiosauria.”
“In recent years, the continual discovery of new fossil material from southwestern China — such as Atopodentatus, with its hammer-shaped jaw, and various genera of saurosphargids with different types of dorsal armor — has challenged traditional views on the origin, migration, and evolution of sauropterygians.”
The newly described sauropterygian species lived approximately 245 million years ago during the Anisian age of the Triassic, a period when ocean ecosystems were still rebounding from the catastrophic mass extinction at the end of the Permian.
Named Spatulidentatus breviceps, the marine reptile had a total body length of around 2.7 m (9 feet).
Its jaws were lined with teeth shaped like small spoons, while its skull was unusually compact, making up only about 5% of the body length.
The animal’s nearly complete and articulated skeleton was recovered from the upper section of the Guanling Formation, a rock formation straddling the border of China’s Yunnan and Guizhou provinces.
Cataloged as GMG10, the fossil is housed at the Geological Museum of Guizhou.
“The specimen is preserved in lateral view, with the trunk exposed on the lateroventral surface,” the paleontologists said.
“The forelimbs and hindlimbs are well preserved except for the distal portions.”
“The rostrum is short; the atlas is unrecognizable, and at least 12 cervical vertebrae are preserved with well-developed cervical ribs.”
Based on preliminary comparisons, the researchers suggest Spatulidentatus breviceps may be closely related to some of the most primitive members of the sauropterygian family: the shell-crushing placodonts and the taxonomically uncertain hammer-jawed Atopodentatus.
“The Anisian Spatulidentatus breviceps from the Yunnan-Guizhou border region of southwestern China provides new material for phylogenetic research on basal sauropterygian evolution,” they concluded.
The team’s paper was published in the journal Geological Review.
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Mei Yang et al. 2026. A new Sauropterygian (Reptilia: Sauropterygia) Spatulidentatus breviceps gen. et sp. nov. from Middle Triassic in border area of Yunnan and Guizhou. Geological Review 72 (4): 1280-1285; doi: 10.16509/j.georeview.2025.11.052
