Utility of crinoid columnals in palaeontology illustrated by a new species: Clare Shale Formation (Carboniferous), Doolin,County Clare,western Ireland |
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| Institution: | 1. University of Silesia, Faculty of Earth Sciences, B?dzińska 60, 41-200 Sosnowiec, Poland;2. Department of Geology, The College of Wooster, Wooster, OH 44691, USA;3. Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu, Estonia;1. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of RAS, Novosibirsk, Russia;2. Novosibirsk National Research State University, Novosibirsk, Russia;1. Genetics Division, Instituto Nacional de Câncer, Rio de Janeiro, Brazil;2. Department of Genetics, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil |
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| Abstract: | Well-preserved specimens, such as complete individuals, crowns and cups, are the common focus for crinoid systematic research. Yet the majority of specimens are disarticulated ossicles which are essentially ignored. The incompleteness of the fossil record is even more so when we ignore potential sources of data. A new species of crinoid comes from a monospecific assemblage from the Pennsylvanian (Upper Carboniferous) of western Ireland. All specimens are from a float block of the Clare Shale Formation (Bashkirian stage) at Fisherstreet Bay, Doolin, County Clare, western Ireland. Heloambocolumnus (col.) harperi gen. et sp. nov. has a pentagonocyclic, heteromorphic column; the small, central lumen is in a shallow, circular claustrum; the articulation is radial symplectial; the crenulae are slightly swollen and peg-like close to the circumference; nodals have rounded, unsculptured epifacets; nodal articular facets are sunken and in which narrow internodals are situated; and circlets of tubercles on epifacet surround priminternodals. These columnals are associated with robust, uniserial brachial ossicles. This crinoid is most likely a cladid. |
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| Keywords: | Pennsylvanian Columnals Preservation Systematics |
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