Tretaspis radialis Lamont and allied species (Trilobita)

Abstract

SummaryRecently discovered specimens from the Portrane Limestone Formation of eastern Ireland are regarded as topotypes of Tretaspis radialis Lament and used to further characterize the species. The features shown by these specimens confirm the close relationship between T. radialis and forms from Zones 2–4 of the Cautleyan Stage of northern England and Wales and allow its differentiation from T. moeldenensis Cave and from another related form of low Rawtheyan age which is here erected as a new species, T. caritus sp.nov.