Beesiiwo (meaning "big lizard") is a genus of hyperodapedontine rhynchosaur from the Late Triassic Popo Agie Formation in Western Wyoming.

These attributes better align with those found in Beesiiwo cooowuse ... [they] suggest it is either a close relative of this taxon or a member of such.

"[1] The generic name, Beesiiwo, is the Arapaho word beesiiwó, which translates to "big lizard" in English.

The specific name, cooowuse , derives from the Arapaho name co’ oowu se’, which refers to the Alcova area of Central Wyoming, an area within traditional Arapaho Tribe land where Beesiiwo was found.

[1] Fitch et al., (2023) recovered Beesiiwo in the Hyperodapedontinae subfamily of Hyperodapedontidae, as a sister taxon to Oryctorhynchus bairdi in a phylogenetic analysis.