Rare Acanthoparypha gibba Russian trilobite

Acanthoparypha gibba, previously called Nieszkowskia tumidus gibbus, is among the very rarest of the trilobites from the Ordovician strata of the Wolchow River region near Saint Petersburg, Russia. While is has resemblance to the spiny Lichids of the region, it is actually a Phacopid, and thus testament that the evolutionary twists and turns of a great Ordovician shallow sea elicited exotic forms across most trilobite families of the time.