The cuticular structure of the 495-Myr-old type species of the fossil worm Palaeoscolex, P. piscatorum (?Priapulida)

Latex impressions of the cuticle of a compression fossil of the ? priapulid Palaeoscolex piscatorum, from the Lower Ordovician of Shropshire, demonstrate a complex ornamentation of sclerites similar to isolated material, e.g. Hadimopanella and phosphatized arrays. Each ‘segment’ is defined by an intercalary zone and bears two rows of sub-circular plates with prominent nodes on the upper surface. The intercalary zone bears two narrow grooves and a series of platelets, similar to but smaller than the plates. The remainder of each segment is occupied by microplates. Palaeoscolex piscatorum is fairly similar to a number of other species, including Gamoscolex herodes and Milaculum elongatum. Present evidence suggests the palaeoscolecidans are priapulid worms (or near relatives). Their abundance, combined with records from Burgess Shale-like occurrences, suggest priapulids were a major component of many Lower Palaeozoic benthic communities.