Abstract

The cladid crinoid Diphuicrinus ohioensis Burke, 1976, was originally described from shallow marine facies of the Middle Pennsylvanian Putnam Hill Limestone of southeastern Ohio. One of the type localities for this taxon is an abandoned quarry in Vinton County, where a small number of articulated cups used in erection of this species was collected. Prior to formal description of this species, multiple isolated calyx ossicles were collected from this locality, but were not analyzed in detail or included in the description of D. ohioensis. The previously unidentified material, described herein, contributes to a more complete record of this taxon. Further, heavily sculptured (nodose) basal and radial plates are nearly ubiquitously encrusted by calcareous tubes, a paleoecological detail not otherwise noted in the description of D. ohioensis or the lithofacies from which material was collected. Encrusters, which consist of at least 2 varieties, are present primarily in depressed areas in between raised nodes. This may reflect post-mortem removal via abrading currents but may alternatively represent preferential encrustation of portions of hard bioclasts characterized by larger, smoother, protected surfaces. This study reinforces the value of isolated crinoid ossicles in paleoecology, paleobiology, and paleoenvironmental analysis.

Highlights

  • Isolated crinoid ossicles, reflecting complete postmortem disarticulation of individuals during extended residence within the taphonomically active zone (Lewis 1980), represent one of the most abundant bioclasts in the Paleozoic rock record (Lowenstam 1957; Ausich 1997)

  • Isolated crinoid ossicles contribute to greater understanding of the internal morphology and intraspecific variability of taxa that are known from a limited number of specimens

  • This locality is the same as “Locality 3” of Burke (1976), a site from which several of the articulated cups that serve as type material for D. ohioensis were collected, namely paratypes USNM (United States National Museum of Natural History) 166575 and USNM 166576

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Summary

Introduction

Isolated crinoid ossicles, reflecting complete postmortem disarticulation of individuals during extended residence within the taphonomically active zone (Lewis 1980), represent one of the most abundant bioclasts in the Paleozoic rock record (Lowenstam 1957; Ausich 1997). Isolated crinoid ossicles contribute to greater understanding of the internal morphology and intraspecific variability of taxa that are known from a limited number of specimens. Careful attention to disarticulated crinoids shows promise for enhancing paleoenvironmental reconstructions, improving understanding of biotic interactions, and increasing records of echinoderm biodiversity and paleobiology. Articulated or partially articulated material is generally needed to formally describe new crinoid taxa.

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