Some disparid crinoids from the Upper Ordovician (Shermanian) Walcott-Rust quarry of New York
Autor: | James C. Brower |
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Rok vydání: | 2008 |
Předmět: | |
Zdroj: | Journal of Paleontology. 82:57-77 |
ISSN: | 1937-2337 0022-3360 |
DOI: | 10.1666/06-077.1 |
Popis: | locrinus trentonensisWalcott, 1883 is characterized by the widest food grooves and the largest covering plates of any of the Walcott-Rust Quarry crinoids, which indicates that the animal captured relatively large food particles with large and widely separated tubefeet. Although iocrinids are generally considered as primitive disparids, their anal sac is unique. the holdfasts ofI. trentonensisconsist of distal stem coils that are tightly wrapped around the columns of other crinoids. the relatively long column ofEctenocrinus simplex(Hall, 1847) was attached to a wide range of shelly substrates by a small irregular and somewhat lobate holdfast. Ectenocrinids ate much smaller food items that were collected by smaller and more tightly packed tubefeet. the ontogeny ofE. simplexillustrates the differences between the food gathering systems of conspecific crinoids from shallow and deep water habitats. the calceocrinidCalceocrinus barrandiiWalcott, 1883 lived with its long stem forming a runner along the seafloor. the crown was movably hinged to the basal circlet and the stem. Moderately wide food grooves were probably present. |
Databáze: | OpenAIRE |
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