Paleontologists in Germany have unearthed an exceptionally well-preserved skeleton of an Early-Jurassic plesiosauroid species called Plesiopterys wildi.
The MH 7 skeleton of Plesiopterys wildi in ventral view. Image credit: Marx et al., doi: 10.7717/peerj.18960.
From a global perspective, the Early Jurassic was characterized by the steady break-up of the supercontinent Pangea and associated climatic fluctuations that produced alternating greenhouse and ice-house conditions.
These paleoenvironmental changes coincided with the radiation of various reptile groups, including Plesiosauria.
The Early Jurassic fossil record of plesiosaurs is especially diverse, with members of Plesiosauroidea, Pliosauridae and Rhomaleosauridae represented by numerous species from Europe, particularly in Germany and England.
The 3-m-long skeleton of Plesiopterys wildi offers new clues about the evolution and geographic distribution of Early Jurassic plesiosaurs.
Dated to 180 million years ago, the fossil was found in the Posidonienschiefer Formation near Holzmaden, southern Germany.
The specimen, referred to as MH 7, is one of the most complete articulated plesiosaur skeletons found in the region.
“Unlike ichthyosaurs and marine crocodile relatives, which dominate the fossil record of this formation, plesiosaurs are comparatively rare,” said Lund University paleontologist Miguel Marx and his colleagues.
“The new discovery, therefore, provides a rare glimpse into the biodiversity of these long-necked marine reptiles.”
“MH 7 represents a subadult individual, refining the known characteristics of this species and confirming its validity as a distinct taxon.”
The phylogenetic analysis indicates that Plesiopterys wildi is an early-diverging plesiosauroid, closely related to Franconiasaurus brevispinus.
“The discovery suggests a gradual evolutionary transition towards more derived cryptoclidids of the Late Jurassic,” the paleontologists said.
“It supports the idea that plesiosaur species may have been regionally distinct within the epicontinental seas of Early Jurassic Europe, reinforcing patterns of paleobiogeographical segregation.”
“The Holzmaden specimen gives us an unprecedented look at Plesiopterys wildi in a more mature stage of development, allowing us to refine our understanding of this species and its place in plesiosaur evolution,” Dr. Marx said.
“It also suggests that distinct plesiosaur communities may have evolved in different regions of the European seas during the Early Jurassic.”
“Our research reinforces that plesiosaurs were already evolving specialized adaptations and distinct regional lineages much earlier than we used to believe,” added Dr. Sven Sachs, a researcher at the Naturkunde-Museum Bielefeld.
“This has important implications for understanding how marine reptiles responded to environmental changes in the Jurassic seas.”
The study was published in the journal PeerJ.
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M. Marx et al. 2025. A new specimen of Plesiopterys wildi reveals the diversification of cryptoclidian precursors and possible endemism within European Early Jurassic plesiosaur assemblages. PeerJ 13: e18960; doi: 10.7717/peerj.18960
