More Platycrinites technical information:

A report by Ausich and Kammer (1990) provides details on how different Platycrinites species were historically defined. In 2009, they re-examined 19 different characteristics of these crinoids and related genera. The new study found that some features were more distinctive than others for separating and defining different species of Platycrinites. They amended the definition of Platycrinites species to include a structure called the tegmen. Tegmens are structures on the top of the calyx. Unfortunately, whole calices are hard enough to find, but views that show tegmens are even rarer. Even where preserved, they are commonly covered by arms, so are hard or impossible to see.  For most of the species that have been reported in Kentucky, including P. penicillus, a tegmen has never been found. Ausich and Kammer (2009) labeled all of the American species of Platycrinites that lacked a tegmen, as “s.1” or “species 1.”  This means they remain in Platycrinites for now, but can’t be confirmed in the genus because they lack tegmens. Hopefully someday specimens will be found to support their placement in the redefined genus, Platycrinites. Platycrinites penicillus is now technically written as P. “s.1” penicillus. The modified species names are still used pending more information, and P. “s.1” penicillus is still used as a guide fossil. 

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Ausich, W.I. and Kammer, T.W., 1990, Systematics and phylogeny of the late Osagean and Meramecian crinoids Platycrinites and Eucladocrinus from the Mississippian stratotype region: Journal of Paleontology, v. 64, no. 5, p. 759–778.

Ausich, W.I., and Kammer, T.W., 2009, Generic concepts in the Platycrinitidae Austin and Austin, 1842 (class Crinoidea): Journal of Paleontology, v. 83, no. 5, p. 694–717.

Baumiller, T.K. and Ausich, W.I., 1996, Crinoid stalk flexibility: theoretical predictions and fossil stalk postures: Lethaia, v. 29, no. 1, p. 47-59.

Butts, C., 1922, The Mississippian Series of eastern Kentucky: Kentucky Geological Survey, Series 6, v. 7, 188 p.

Carr, D.D., 1973, Geometry and origin of oolite bodies in the Ste. Genevieve Limestone (Mississippian) in the Illinois Basin: Indiana Geological Survey, Bulletin 48, 80 p.

Dever, Jr., G.R., 1999, Tectonic implications of erosional and depositional features in upper Meramecian and lower Chesterian (Mississippian) rocks of south-central and east-central Kentucky: Kentucky Geological Survey, Series 9, Bulletin 5, 67 p.

Ettensohn, F.R., Rice, C.L., Dever, Jr., G.R. & Chesnut, D.R., 1984, Slade and Paragon formations – new stratigraphic nomenclature for Mississippian rocks along the Cumberland escarpment in Kentucky. U.S. Geological Survey Bulletin 1605, 37 p.

Ettensohn, F.R., Ausich, W.I., Kammer, T.W., Johnson, W.K., and Chesnut, D.R., Jr., 2003, Carboniferous echinoderm zonation in the Appalachian Basin, eastern USA, in Wong, Th. E. (ed.): Proceedings of the XVth International Congress on Carboniferous and Permian Stratigraphy. Utrecht, the Netherlands, 10–16 August 2003. Royal Netherlands Academy of Arts and Sciences, p. 177-189.

Maples, C.G., and Waters, J.A, 1987, Redefinition of the Meramecian/Chesterian boundary (Mississippian): Geology, v. 15, no. 7, p. 647–651.

McFarlan, A.C., 1943, Geology of Kentucky: Lexington, Kentucky, University of Kentucky, 531 p.

Rao, C.P. and Mann, C.J., 1972, Quantitative environmental analysis of Ste. Genevieve Limestone (Mississippian), southern Illinois and eastern Missouri: The Journal of Geology, v. 80, no. 4, p. 464480.

Rice, C.L., Sable, E.G., Dever, Jr., G.R. & Kehn, T.M., 1979. The Mississippian and Pennsylvanian (Carboniferous) systems in the United States – Kentucky. U.S. Geological Survey Professional Paper 1110-F, p. F1–F32.

Sable, E.G., and Dever, G.R., Jr., 1990, Mississippian rocks in Kentucky: U.S. Geological Survey Professional Paper 1503, 125 p.

Swan, D. H., 1963, Classification of Genevievian and Chesterian (Upper Mississippian) rocks of Illinois: Illinois Geological Survey Report of Investigations, v.  216, 91 p.

Ubaghs, G., Moore, R.C., Rasmussen, W., Lane, N.G., Breimer, A., Strimple, H.L., Brower, J.C., Jeffords, R.M., Sprinkle, J., Peck, R.E., Macurda, D.B., Jr.,Meyer, D.L., Roux, M., Sieverts-Doreck, H., Fay, R.O., and Robsion, R.A., 1978, Part T—Echinodermata 2, in Moore, R.C., ed., Treatise of Invertebrate Paleontology: Geological Society of America and University of Kansas Press, v. 2-3, p. 403–1027 (v. 2 is p. 404–812, v. 3 is p. 813–1027).

Webster, G.D., 1999, Bibliography and Index of Paleozoic Crinoids, Coronates, and Hemistreptocrinoids 1758–1999: Geological Society of America on-line database,, accessed 2006.

Weller, J.M., 1926, Faunal zones in the standard Mississippian section: Journal of Geology, v. 34, p. 320–335.

Weller, J.M., 1931, The Mississippian fauna of Kentucky, in Jillson, W.R., ed., Paleontology of Kentucky: Kentucky Geological Survey, ser. 6, v. 36, p. 251–290.

Willman, H.B., 1975, Handbook of Illinois stratigraphy: Illinois State Geological Survey, Bulletin 95, 261 p.


Text, photographs, and illustrations by Stephen Greb

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Last Modified on 2022-08-26
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