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Document Type

Research

Keywords

Late Mississippian; Chesterian; Talarocrinus Zone; Pella Formation; Mahaska County, Iowa; Echinodermata; Echinoidea; Echinocystitidae; Praepholidocidaris pellaensis; Pholidocidaris; paleoecology

Abstract

Praepholidocidaris pellaensis, n. gen., n. sp., is described from basal Chesterian rocks in the vicinity of Oskaloosa and Givin, Mahaska County, Iowa. The new genus is characterized by its small number of ambulacral and interambulacral plate columns, adorally expanded ambulacra, unequal ambulacrals with perforate primary spines, and interambulacrals with primary spines only on adradial plate columns. Age relationships of the Pella Formation and the paleoecology of its echinoderm fauna are reviewed. It is concluded that the echinoderms represent an opportunistic assemblage and the bulk of the echinoderm fauna supports assignment of unit C of the formation to the Talarocrinus Zone (of Horowitz and Strimple, 1974), basal Chesterian.

Publication Date

September 1977

Journal Title

Proceedings of the Iowa Academy of Science

Volume

84

Issue

3

First Page

98

Last Page

105

Copyright

© Copyright 1977 by the Iowa Academy of Science, Inc.

Language

EN

File Format

application/pdf

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