Ancistronychus paradoxus was named by Gonçalves and Sidor (2019). Its type specimen is PEFO 42805/UWBM117331, a limb element (isolated manual ungual phalanx), and it is a 3D body fossil. Its type locality is Kaye Quarry PFV 410, UWBM C2226, which is in a Norian terrestrial mudstone in the Chinle Formation of Arizona. It is the type species of Ancistronychus.