• ✓Bipedal, back horizontal, tail held straight out off the ground
• ✓Mouth closed, lips covering the teeth so none are visible
• ✕Palms facing each other, not turned down or danglingHands held forward with claws pointing down
• ✓Three weight-bearing toes on each foot
• ✓Long, narrow skull with small triangular horns in front of the eyes and low snout ridges
• ✓Strong arms with three large curved claws
• ✓About 9 m long, slimmer than T. rex, small scales
• ✓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 Allosaurus, a carnivore Allosauridae dinosaur from the Late Jurassic (about 155–143 million years ago). Bipedal with the back held roughly horizontal and the tail held straight out behind for balance, never dragging on the ground. NOT standing upright like a kangaroo. Mouth closed with all teeth fully hidden behind scaly lips, like a monitor lizard. NO visible teeth. A long, narrow skull with a pair of small triangular horns just in front of the eyes and low ridges along the top of the snout. Reference: Allosaurus is a genus of theropod dinosaur that lived 155 to 143 million years ago during the late Jurassic period. The first fossil remains that could definitively be ascribed to this genus were described in 1877 by Othniel C. Marsh. The name "Allosaurus" means "different lizard", alluding to its lightweight vertebrae, which Marsh believed were unique. Anatomy: hands held with palms facing each other (not pronated, not palms-down, not dangling); three main weight-bearing toes on each foot; strong arms with three large curved claws on each hand; about 9 meters long, slender and agile compared to tyrannosaurs, skin of small scales. Full body in side view, whole animal visible, standing in a semi-arid Late Jurassic floodplain like the Morrison Formation of western North America, with conifers, cycads, ginkgoes, tree ferns and ferns along a river, 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