A newly discovered marine reptile, Lijiangosaurus yongshengensis, is rewriting the story of how long necks evolved in aquatic reptiles. Fossil remains unearthed in China reveal this creature, which lived approximately 247 to 241 million years ago, possessed an exceptionally long neck containing a remarkable 42 vertebrae – double the typical number found in similar species from the same period. This discovery pushes back the origins of extreme neck elongation in marine reptiles, demonstrating it predates the evolution of plesiosaurs, the iconic long-necked creatures of the Mesozoic Era.
A Triassic Pioneer
Lijiangosaurus belonged to the nothosaurs, a group of early marine sauropterygians – reptiles adapted to life in the sea. These animals, capable of growing up to 7 meters long, swam using paddle-like limbs and hunted fish and squid with a meshwork of slender teeth. However, Lijiangosaurus stands out due to its unique neck structure. While plesiosaurs are famed for their elongated necks, this discovery proves that extreme cervical elongation wasn’t exclusive to them, and in fact, emerged much earlier in sauropterygian evolution.
Redefining Evolutionary Timelines
For years, scientists believed that long necks were a defining feature of plesiosaurs and their immediate ancestors, the pistosaurs. The discovery of Lijiangosaurus challenges this view. The animal’s 42 cervical vertebrae suggest that extreme neck elongation evolved independently in early sauropterygians, before the rise of plesiosaurs. This suggests the trait was not a singular evolutionary event, but a recurring adaptation in marine reptiles.
Unique Adaptations
Beyond its elongated neck, Lijiangosaurus also exhibited a unique type of accessory intervertebral articulation. This structure, unlike anything seen in other reptiles, likely reduced body undulation during swimming, providing greater stability and maneuverability in the water. The discovery highlights the high degree of plasticity in the vertebral column of early sauropterygians, demonstrating their ability to adapt rapidly to marine environments.
New Fossil Site Unlocks Ancient History
The fossilized remains of Lijiangosaurus were found at a previously unknown early Middle Triassic locality in China’s Yunnan province, near the eastern Tibetan Plateau and northern Myanmar. This new site differs from previously documented fossil-rich regions in southwestern China, suggesting that the area holds untapped potential for further discoveries.
The findings, published in the journal Communications Biology, provide crucial insights into the early evolution of marine reptiles. Lijiangosaurus yongshengensis demonstrates that extreme cervical elongation was not a late development in plesiosaurs, but a much earlier adaptation that emerged in the Triassic Period, shaping the evolutionary trajectory of sauropterygians for millions of years. This discovery underscores the complexity of marine reptile evolution and highlights the importance of continued paleontological research in unlocking the secrets of ancient life
