Camerate and disparid crinoids from the late Kinderhookian Meadville Shale, Cuyahoga Formation of Ohio

Abstract

Crinoids were first reported from the Cuyahoga Formation in northeastern Ohio by James Hall in 1863. However, these crinoids have not been re-examined in detail since the late nineteenth century. With the restudy of classical and more recent collections, ten (nine camerate and one disparid) species-level taxa are recognized from the late Kinderhookian Meadville Shale Member, Cuyahoga Formation, including the camerates Amphoracrinus viminalis (Hall, 1863); Aorocrinus helice Hall, 1863; Aorocrinus meyeri n. sp.; Aryballocrinus martini n. sp.; Cusacrinus daphne (Hall, 1863); Platycrinites s.l. contritus (Hall, 1863); Platycrinites s.l. graphicus (Hall, 1863); Platycrinites s.l. lodensis (Hall and Whitfield, 1875); and Platycrinites s.l. burkei n. sp. In addition, Halysiocrinus sp. is the first disparid reported from this fauna. Platycrinites s.l. bedfordensis (Hall and Whitfield, 1875) is designated a nomen dubium. Growth is evaluated for Aorocrinus helice and Cusacrinus daphne, which had contrasting development. The growth of the Aorocrinus helice calyx was largely not allometric but that of the primaxil plate was, suggesting the arms may have grown allometrically. In contrast, much of the calyx of Cusacrinus daphne displayed allometric growth.