A new plesiosaur from Holzmaden

PUBLICATION — Sachs, S. & D. Madzia. 2025. An unusual early-diverging plesiosauroid from the Lower Jurassic Posidonia Shale of Holzmaden, Germany. PeerJ 13: e19665. doi:10.7717/peerj.19665

Figure: reconstruction of Plesionectes longicollum (artwork: Peter Nickolaus)

Plesionectes longicollum is a new plesiosauroid taxon from the lower Toarcian (Lower Jurassic) Posidonia Shale of Holzmaden, Germany, based on a nearly complete skeleton discovered in 1978. It exhibits a distinctive combination of anatomical features, including an extraordinarily long neck. Plesionectes is based on the oldest plesiosaur specimen from the Holzmaden area, expanding both the known diversity and stratigraphic range of Toarcian plesiosaurs in the region.