This is an unusual type of Ordovician trilobite. It is a complete Illaenus tauricornus from St. Petersburg, Russia. Most Illaenus have rounded genal angles, and do not have genal spines. This type has long, curving genal spines on each side - this specimen showcases these spines beautifully. The trilobite itself is complete and very inflated. The natural caramel coloration is striking, and the detail is excellent. The large eyes also display prominently. The trilobite is well showcased on the natural-edged block of limestone. This is a fine example of this spiny Illaenus trilobite.