Ordovician trilobites with soft parts in African West Gondwana, European peri-Gondwana and Avalonia: a review

A review of all currently known Ordovician trilobites with soft parts described or figured from West-Gondwana, European peri-Gondwana and Avalonia shows remains of the digestive system in 19 species. In comparison, remains of antennae and/or walking legs are known only in five species. Soft parts are known in Asaphidae, Bathycheilidae, Calymenidae, Cheiruridae, Dalmanitidae, Harpidae, Lichidae, Nileidae, Odontopleuridae and Trinucleidae. Exceptionally preserved trilobites originate from the Late Tremadocian Mílina Formation and Fezouata Shale, Middle Darriwilian Šárka and Llanfallteg formations, early Sandbian Tafilalt and Letná Konservat-Lagerstätten and Katian Bohdalec Formation. Levels containing exceptionally preserved trilobites in these units are characterized by prevailing fine-grained sediments with the exception of the Early Sandbian Lower Tafilalt and Letná Lagerstätten.