A comprehensive osteological description of the plesiosaurid Seeleyosaurus
Seeleyosaurus guilelmiimperatoris
is an early plesiosauroid from the Lower
Jurassic Posidonia Shale of Germany. Although
historically important and known from two nearly complete
skeletons, its anatomy remained poorly understood. The new
study provides a full osteological description of Seeleyosaurus
and discusses the taxonomy and phylogeny of early
plesiosauroids. Seeleyosaurus is a microcleidid closely related to Microcleidus,
and is distinct from Plesiopterys.
PUBLICATION: Sachs, S., Madzia, D., Marx, M., Roberts, A. J., Hampe, O., Kear, B. P. 2025. The osteology, taxonomy, and phylogenetic placement of Seeleyosaurus guilelmiimperatoris (Plesiosauroidea, Microcleididae) from the Lower Jurassic Posidonia Shale of Germany. The Anatomical Record: 1–64. https://doi.org/10.1002/ar.25620