[1][2] Bottosaurus harlani is predominantly found from Late Cretaceous strata of Maastrichtian age, such as the Hornerstown Formation and New Jersey Greensands.

[3][4] New material has been reported from the Rhems and Williamsburg Formations of the Black Mingo Group of the South Carolina coastal plain that dates back to the Danian and Thanetian stages of the Paleocene epoch, suggesting that Bottosaurus had survived the Cretaceous–Paleogene extinction event and lived through much of the early Paleogene period.

[3] The species is based on substantial craniomandibular and postcranial material and more solidly places Bottosaurus on the younger side of the Cretaceous-Paleogene boundary.

The teeth had a "wrinkled" enamel surface and prominent annual rings with vertical ridges running down them.

A short, massive lower jaw that is nearly circular in cross-section is evident from remains of the type species B. harlani.