Illaenus tauricornis is a species of trilobites from Russia and Morocco, from the middle Ordovician.

The Latin species name tauricornis means "bull-horned", with reference to the shape of the genal spines.

Illaenus tauricornis can reach a length of about 57 millimetres (2.2 in).

The cephalon has a high profile and recurved genal spines.

Eyes are distant from the axis of the head, situated nearer to the edge.