An echinoderm Lagerstatte from the Upper Ordovician (Katian), Ontario: taxonomic re-evaluation and description of new dicyclic camerate crinoids

The Upper Ordovician (lower Katian) Bobcaygeon and Verulam formations from the Lake Simcoe region of Ontario contain a highly diverse echinoderm assemblage that is herein recognized as a Konservat-Lagerstatte. Although fossil crinoids have long been recognized from these formations, the fauna has not received a comprehensive taxonomic evaluation since Springer's classic 1911 monograph. Recent extensive collection and preparation of new material from the Bobcaygeon and Verulam formations near Brechin, Ontario recovered numerous exceptionally preserved crinoid specimens with arms, stems, and attachment structures intact. The Brechin Lagerstatte is the most taxonomically diverse Katian crinoid fauna, with more than 20 crinoid genera represented in this collection. Here, all dicyclic crinoids belonging to subclass Camerata from the Brechin Lagerstatte are evaluated. The following four genera and seven species are described from the fauna, including one new genus and four new species: Reteocrinus stellaris, Reteocrinus alveolatus, Archaeocrinus sundayae n. sp., Archaeocrinus maraensis n. sp., Priscillacrinus elegans n. gen. n. sp., Cleiocrinus regius, and Cleiocrinus lepidotus n. sp. The exceptional preservation of this collection provides an opportunity to describe more fully the morphologic and ontogenetic details of known Ordovician crinoid taxa, to conduct a taxonomic re-evaluation of many species, to describe new taxa, and to provide a framework for subsequent studies of crinoid community paleoecology.