Acanthoclema (Rhabdomesina, Cryptostomata) from the Devonian of Europe
Ernst, A. (2013). Acanthoclema (Rhabdomesina, Cryptostomata) from the Devonian of Europe, in: Ernst, A. et al. Bryozoan Studies 2010. Lecture Notes in Earth System Sciences, 143: pp. 45-58. http://dx.doi.org/10.1007/978-3-642-16411-8_4
In: Lecture Notes in Earth System Sciences. Springer: Heidelberg; Berlin. ISSN 2193-8571; e-ISSN 2193-858X, meer
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Classification > Taxonomy
Geological time > Phanerozoic > Paleozoic > Palaeozoic > Devonian
Rhabdomesina † [WoRMS]
ANE, Europa [Marine Regions]
Marien/Kust |
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| Abstract |
The rhabdomesine genus Acanthoclema Hall, 1886 is known from the Devonian of North America and Eurasia. Many species referred to this genus were previously understood in a broad concept but do not belong to it. Six species of Acanthoclema are reported from the Devonian of Europe, which consistently show morphological characters shared with the type species. The generic diagnosis of Acanthoclema has been emended. The studied material was used for cluster analysis in order to reveal relationships between the six species of Acanthoclema and to compare them with Nikiforovella gracilis, a representative of the morphologically most similar genus. It is resumed that Nikiforovella derived from Acanthoclema in the Lower Devonian. These two genera show completely different trends in their evolution: a decrease of number of acanthostyles and metazooecia in Acanthoclema, and an increase of their number in Nikiforovella. A test using cluster analysis showed that Morisita’s index is very useful for the heterogeneous data. |
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