Acathoparypha gibba Dramatic Russian Phacopid Trilobite

Description: Coming from the nearly half billion year old Middle Ordovician Asery Level deposits of the Wolchow River region near Saint Petersburg, Russia, this is an example of a member of the Order Phacopida, Family Cheiruridae called Nieszkowskia tumidus gibbus (now called Acanthoparypha gibba). Its affinities with the Cheirurids are apparent, but there are substantial differeneces as well. The trilobite itself is 58 mm long (measured along the curve) and 40 mm wide at the dramatically backswept genal spines. The trilobite is enrolled in a defensive posture, and has been prepared entirely free of the matrix, a time-consuming task. It comes with a square matrix that allows it to pivot freely for display. For a prone example of this same taxon, please see my other offerings.