Middle Mississippian disparid crinoids from the midcontinental United States

Abstract

Systematic restudy of Lower Mississippian disparid crinoids from the midcontinental United States results in the recognition of nine valid species and one left in open nomenclature. Although disparid crinoids are not diverse, they may be locally abundant and be the dominant crinoids in certain settings. The following species are considered valid:Catillocrinus tennesseeaeShumard,Catillocrinus wachsmuthi(Meek and Worthen),Eucatillocrinus bradleyi(Meek and Worthen),Halysiocrinus bradleyi(Meek and Worthen),Halysiocrinus cumberlandensisnew species,Halysiocrinus springeriBrower,Halysiocrinus tunicatus(Hall),Synbathocrinus blairiMiller, andSynbathocrinus swalloviHall. Several species are placed into synonymy.Catillocrinus shumardiSpringer andC. turbinatusare considered junior synonyms ofC. tennesseeae. Halysiocrinus granuliferusandH. perplexusare regarded as junior synonyms ofH. tunicatus. Synbathocrinus angularisMiller and Gurley,S. granulatus(Wood),S. granuliferusWetherby,S. robustusShumard, andS. troosti(Wood) are deemed junior synonyms ofS. swallovi.The youngest (Meramecian) North American calceocrinids,Halysiocrinussp., are reported, herein, from the Harrodsburg and Salem Limestones of Indiana.