Ichthyosaur marine reptile — Stenopterygius quadriscissus

Geologic period: Early Jurassic — Toarcian

Age: Early Toarcian.

Feeding: Predatory marine feeder. Fossil stomach contents and teeth provide evidence for prey use.

Locomotion: Fully aquatic swimming.

Body plan: Streamlined fish-shaped reptile with paddle-like limbs, a long snout and powerful tail-driven swimming anatomy.

Evidence: Skeletons, soft-tissue outlines, stomach contents and pregnant individuals provide unusually rich evidence.

Why it matters: Stenopterygius demonstrates how completely a reptile lineage could become adapted to marine life. Exceptional specimens also preserve embryos and body outlines.

Plain Language Identity: A streamlined Early Jurassic ichthyosaur exceptionally well known from the Posidonia Shale of Germany.

What You Are Looking At: An ichthyosaur skeleton representing an animal strongly adapted for open-water swimming.

Ecosystem: Early Jurassic marine ecosystem.

Formation: Posidonienschiefer Formation for classic German material.

Find Location: Germany.

Preservation: Exceptional marine reptile fossil preservation.

Open Questions: Do not treat its fish-like body as evidence that ichthyosaurs were fish. They were reptiles.

Source Urls: https://naturalhistory.si.edu/visit/virtual-tour/current-exhibits/deep-time-virtual-tour-fossil-list; https://www.si.edu/object/nmnhpaleobiology_3426629; https://palaeo-electronica.org/content/2020/3078-revision-of-hauffiopteryx

Enrichment Method: SAGE curated research pass; title + scientific name + source scene matched; historic taxonomy retained where relevant; evidence separated from inference

Scientific name: Stenopterygius quadriscissus

Evidence / representation: comparative_taxon_visual

comparative_taxon_visual

Jurassic Giants: Size, Teeth, Armor and Survival.

Media license: Public domain