• ✓About 3.5 m long
• ✓Very long neck, about half the body length, held straight forward, not raised out of the water like a swan
• ✓Small head with many slender needle-like teeth
• ✓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 Early Jurassic sea
• ✓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 Plesiosaurus, a plesiosaur (a long-necked marine reptile, not a dinosaur) from the Early Jurassic (about 195 million years ago) of Lyme Regis, England. Anatomy: about 3.5 m long; a very long neck, about half of the body length, held straight forward and roughly level, NOT raised up out of the water like a swan; a small head with many slender, needle-like teeth; 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 Early Jurassic sea, 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