Whiterockian (Ordovician) crinoid fauna from the Table Head Group, western Newfoundland, Canada

Abstract

Three crinoids are described from the Table Point Formation, Table Head Group (Whiterockian-Llanvirn) from Aguathuna quarry, Port au Port Peninsula, western Newfoundland, including Trichinocrinus terranovicus Moore and Laudon, Isotomocrinus apheles n.sp., and Brechmocrinus eos n.gen. and n.sp. Trichinocrinus terranovicus is one of the oldest camerate crinoids known. It was previously described from a single specimen, and the numerous additional specimens confirm that this crinoid had few fixed calyx plates, demonstrate that the small "pinnulets" are spines, and reveal that this crinoid had a very unusual posterior. The posterior interradius may indicate that all crinoids had homologous plating in the posterior interray rather than the camerate posterior interray being distinct from other crinoids. Isotomocrinus apheles n.sp. is the oldest species of this Ordovician genus, and Brechmocrinus eos n.gen. and n.sp. is the third known Arenig to Llanvirn cladid with a compound radianal.