Oklahoma State Dinosaur: Acrocanthosaurus atokensis

Acrocanthosaurus is one of the few North American theropods whose footprints have been attributed with reasonable confidence. The large three-toed trackways at Dinosaur Valley State Park in Glen Rose, Texas — along the Paluxy River — are widely attributed to Acrocanthosaurus based on size and Early Cretaceous age. These are the most-visited Early Cretaceous theropod tracks in North America. Additional trackways in Arkansas and possibly Wyoming extend the attribution further. Oklahoma designated an animal whose physical presence — even the impression of its feet — reached across state lines.

Oklahoma Senate Bill 1048 designated Acrocanthosaurus atokensis as the state dinosaur in 2006. The case rested on something no other state can claim about its designated dinosaur: the species name is a permanent geographic record of the discovery county. Atokensis — 'of Atoka' — was assigned by Oklahoma paleontologists in 1950 and has never changed. Every citation in the scientific literature carries Oklahoma's county name.

Oklahoma also chose a predator. Most state dinosaurs are herbivores — hadrosaurs, sauropods, ceratopsians. Acrocanthosaurus was the apex predator of its world: 11–12 meters, roughly 6,000 kilograms, with no competitor of comparable size in Early Cretaceous North America. The designation was a deliberate choice, not a default.

There is one awkward detail the designation created. The most complete Acrocanthosaurus specimen — 'Fran,' found by Oklahoma collectors Sid and Cephis Hall in McCurtain County in 1983 — was acquired by the North Carolina Museum of Natural Sciences in Raleigh, where it is now mounted on display. Oklahoma's state dinosaur is best seen in North Carolina. The original type material, however, remains at the Sam Noble Museum in Norman — the specimens that gave the animal its name and its county.