• ✓About 6–7 m long, not a 25 m giant
• ✓Large head about a fifth of body length, long strong jaws, big cone-shaped teeth
• ✓Short, thick neck
• ✓Four long wing-shaped flippers of similar size, broad flat body, short tail
• ✓Smooth skin, dark above and pale below
• ✓Whole body in side view, swimming
• ✓Underwater in a shallow Middle Jurassic sea over Europe
• ✓Only this one species; no dinosaurs, text, people or modern objects

Checked by Claude Opus 5.5 (checked item by item from the image) on Nov 4, 2026. The score is the share of checklist items the image gets right; it is not an expert scientific review.

Prompt used to create the image

Scientifically accurate paleoart of Liopleurodon, a pliosaur (a short-necked plesiosaur, a marine reptile, not a dinosaur) from the Middle Jurassic (Callovian, about 165 million years ago) of England and France. Anatomy: about 6 to 7 m long, not a 25 m sea monster; a large head about one fifth of the body length, with long, strong jaws and big cone-shaped teeth; a short, thick neck; four long, wing-shaped flippers of similar size, a broad flattened body and a short tail; smooth skin, dark above and pale below (countershading). Full body in side view, swimming underwater, whole animal visible, underwater in a warm, sunlit, shallow Middle Jurassic sea over Europe, a few small fish nearby for scale. Natural history museum illustration style, realistic textures and natural daylight, muted natural colors. Only this one species; no dinosaurs, no text, no labels, no humans, no boats, no modern objects.

Facts in the prompt come from Wikipedia (en) and Paleobiology Database