Early Silurian (Llandovery) Crinoids from the Lower Clinton Group, Western New York State - BAP #360
Early Silurian (Llandovery) crinoids have been poorly known. The present paper describes 26 species and six unassigned columnal taxa of Early Silurian crinoids on the basis of new and well preserved fossils from the lower Clinton Group of western New York. The new material, comprising eighteen genera, and unclassified skeletal material, spans the late middle Llandovery to the latest Llandovery and has been derived from several lithostratigraphic units. The Reynales Formation (Aeronian) contains the following new genera: Dynamocrinus, Thaerocrinus, Haptocrinus, and Prolixocrinus; new species include Dynamocrinus robustus, Thaerocrinus crenatus, Haptocrinus calvatus, Prolixocrinus nodocaudis, and Macrostylocrinus sp. Two species of disparid Eomxelodacrinu,. E. sparwus Eckert and E. uniformis Eckert, and one unusual camerate, Stipalocrinus hulveri Eckert and Brett, have been previously described from the Reynales Limestone. Compsocrinus relictus, Dendrocrinus ursae, and an unidentified camerate occur in the laterally equivalent Bear Creek Shale. New taxa from the Wolcott Limestone (lower Telychian) include the Atalocrinacea, new superfamily; Atalocrinidae, Callistocrinidae, and Anisocrinidae, new families; Callistocrinus, Tormosocrinus, Alalocrinus, Aclistocrinus, Kyphosocrinus, and Scapanocrinus, all new genera; and the species Callistocrinus tesselatus, Tormosocrinus furberi, Alalocrinus arclus, Aclistocrinus capistralus, Kyphosocrinus tetreaulti, Scapanocrinus inuricalus, Myelodactylus linae, Euspirocrinus wolcottense, Dendrocrinus aphelos, D. bactronodosus, Haptocrinus sp., Anisocrinid sp., and an unidentified flexible crinoid. Protaxocrinus anellus n. sp. and five unidentified columnal types occur in the upper Telychian Willowvale Shale. Taxonomic revisions also necessitate reassignments of three previously described taxa. The disparid Macnanuiratylus Bolton is synonymized with Eomyelodactylus, the flexible crinoid Cudochirus americanus Springer is reassigned to Prolixocrinus n. gen. and the cladid genus Quinquecaudcx Brower and Veinus, 1981, is synonymized with Dendrocrinus. The erroneous species Glyptocrinus plumosus Hall is reviewed; the cotype specimens in part represent the cirral column of a myelodactylid disparid crinoid here tentatively assigned to Eoniyelodatyhis (E. plumosus (Hall)); the remaining material consists of columnals and pluricolumnals probably belonging to Haptocrinus.
J.D. Eckert, C. Brett
Pages: 88, 26 text-figs., 9 tables
Issue: BAP 360
Year published: 2001