TRILOBITE Paraceraurus exsul

This is an exquisitely preserved and beautifully prepared example of Paraceraurus exsul, a large, spiny Ordovician period trilobite from the Saint Petersburg region in Russia. Trilobites from this area are often beautifully preserved in fine limestone. This piece has been expertly prepared, and the long Genal spines that trail back from the cheeks have been completely cleared from the matrix. This specimen shows minimal restoration, confined to the long pygidial spines at its very rear. This is a superb example of this rare species, and a serious showpiece for the collector.

Trilobites are a type of extinct arthropod probably most closely related to modern Horseshoe crabs. In response to a growing number of predators and diverse habitats various species of trilobites had highly developed eyes, retractable antennae, and even protective spines. Trilobites range in size from 1/25 to about 28 inches. Their exoskeletons were composed of extremely hard calcite and calcium phosphate minerals to protect the soft internal organs, and as a result they are quite well represented in the fossil record.