• ✓Extremely long neck, about half the body length
• ✕Quadrupedal on pillar legs, small head, tail off the groundTail tip hangs down almost to the ground
• ✓Whole animal visible in side view
• ✓Scene matches the period and the fossil site
• ✓No text, people or modern objects

Checked by Claude Opus 5.5 (checked item by item from the image) on Oct 28, 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 Mamenchisaurus, a herbivore Mamenchisauridae dinosaur from the Late Jurassic (about 160–145 million years ago). An extremely long neck making up about half of the whole body length, held roughly horizontal to moderately raised. Reference: Mamenchisaurus is an extinct genus of sauropod dinosaurs known for their remarkably long necks, which made up nearly half the total body length. Numerous species have been assigned to the genus; however, the validity of these assignments has been questioned. Fossils have been found in the Sichuan Basin and Yunnan Province in China. Anatomy: quadrupedal on pillar-like legs, small head, tail held off the ground. Full body in side view, whole animal visible, standing in a Late Jurassic river floodplain like the Phu Kradung Formation of northeastern Thailand, with conifers, cycads, tree ferns and ferns, no grass and no flowering plants. Natural history museum illustration style, realistic textures and natural daylight, muted natural colors. No text, no labels, no humans, no modern objects.

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