Macrostylocrinus bornholmensis Laursen, 1940, a forgotten Silurian crinoid from Denmark |
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| Authors: | Stephen K Donovan Vivianne Berg-Madsen |
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| Institution: | 1. Taxonomy and Systematics Group, Naturalis Biodiversity Center, Postbus 9517, 2300 RA, Leiden, The Netherlands;2. Museum of Evolution, Norbyvägen 16, SE 752 36, Uppsala, Sweden |
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| Abstract: | The monobathrid camerate crinoid Macrostylocrinus bornholmensis Laursen has an unfortunate history. It was published in a journal not commonly consulted by echinoderm workers and, worse, in time of war; written in a language not in common use for crinoid studies; and described by a stratigrapher, not an expert on pelmatozoans. These and other factors combined to ensure that M. bornholmensis has not been reassessed since it was first described almost 80?years ago, despite belonging to a genus well-known from the Lower Palaeozoic. Macrostylocrinus bornholmensis is Llandovery (Telychian) and not Wenlock as has been reported elsewhere. Diagnostic features include a column that does not bear radices close beneath the cup; a heteromorphic mesistele with five orders of regularly inserted internodals; three basal plates; smooth thecal plates with central folds following rays; and ten pinnulate free arms that are biserial distally. Macrostylocrinus bornholmensis is distinctly different in morphology from well-known, congeneric species described from the Lower Palaeozoic of northern Europe. |
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| Keywords: | Bornholm Llandovery Telychian Monograptus spiralis Zone Systematics |
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