[1] Based on the morphology of the claws, Unguinychus appears to be most similar to Skybalonyx, another possibly fossorial drepanosaur from the Chinle Formation of Arizona.

[2] The Unguinychus fossil material, was discovered in sediments of the Garita Creek Formation (Homestead Site) on a cattle ranch in San Miguel County, New Mexico.

The holotype specimen, LF 5575, consists of a manual ungual (hand claw) from the second digit, missing the tip.

While these bones may also belong to Unguinychus, Pugh et al. (2024) refrained from making this referral due to a lack of associated and overlapping skeletal material.

[1] In 2024, Pugh et al. described Unguinychus onyx as a new genus and species of drepanosaurid based on these fossil remains.