A 245-Million-Year-Old Reptile Went Into the Rock and Kept Its Lunch

A marine reptile died 245 million years ago, sank into the seafloor of the ancient Tethys Ocean and kept its lunch. Researchers found fish scales still inside its digestive tract.

The fossil is Austronaga minuta, a 2-foot (60-centimeter) long-necked marine reptile from China, a distant cousin of the lineage that eventually gave rise to dinosaurs, crocodiles and birds. Its near-complete skeleton was already known, but a new international study revealed something far stranger: the organs came with it. Using ultraviolet-light photography and chemical analysis, scientists identified a sac-like stomach, a loosely coiled intestine and a liver.

The liver was still reddish. Researchers believe the color came from hemoglobin-derived material, with iron enrichment supporting that interpretation.

That makes this the oldest largely complete digestive system ever identified in a reptile. It also offers a rare look at how an early relative of dinosaurs adapted to life in the sea. Austronaga had a simple, single-chambered stomach, unlike the more complex stomachs of modern birds and crocodiles. Its body had already developed specialized swimming limbs, but its digestive system remained comparatively simple.

And the fish scales provide a particularly intimate detail: this animal had eaten shortly before it died. Its last meal became part of the fossil record alongside its skeleton and organs.

The rock kept the anatomy. Now paleontology is learning to read the chemistry.

Read the full story at Staatliches Museum für Naturkunde Stuttgart, July 29, 2026

Hot Take: A quarter-billion years is a long time to keep a meal on the books. The fossil record apparently does not believe in closing out a tab.