Universität zu Köln

Bohaty, Jan (2011). Revision of the flexible crinoid genus Ammonicrinus and a new hypothesis on its life mode. Acta Palaeontol. Pol., 56 (3). S. 615 - 640. WARSAW: INST PALEOBIOLOGII PAN. ISSN 1732-2421

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Abstract

The lecanocrinid Ammonicrinus (Flexibilia) is newly interpreted based on new material from the Middle Devonian of the Rhenish Massif (Eifel and Bergisches Land, Germany). The species have echinoid-like tubercles on the attachment and on the column, which bear articulated spines. The intraspecific variability of the column is discussed for three facies-controlled morphotypes, herein classified as standard exposed- or encased roller-type and the rare settler-type. New specimens have floating transitions between different plate sculpturing and between those individuals with none or one to several columnals with herein termed lateral columnal enclosure extensions on the proximal-most, barrel-like dististele and the following mesistele, which is solely distinguished by these extensions. Based on this interpretation, Ammonicrinus kongieli is evaluated as a subjective junior synonym of Ammonicrinus sulcatus. The latter species was first recognised from the Eifel (Germany). Ammonicrinus wachtbergensis, from the upper Eifelian of the Eifel, is declared a subjective junior synonym of Ammonicrinus doliiformis. The first nearly complete specimen of Ammonicrinus kerdreoletensis is described from the lower Eifelian of Vireux-Molhain (southern Ardennes, France). Two new species are described: Ammonicrinus jankei sp. nov. and Ammonicrinus leunisseni sp. nov. A functional morphologic trend in perfecting the crown encasement by continuous modification of the lateral columnal enclosure extensions of the mesistele from the Eifelian to the Givetian, indicates a vagile benthic predator-driven evolution of ammonicrinids in the Eifel area. Several ammonicrinid species are herein defined as spined soft-bottom dwellers, feeding in low-intensity current water, possibly through a self-produced water flow. The first known postmortem encrusting epizoans on ammonicrinid endoskeletons are reported.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Bohaty, Jan UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-489432
DOI:	10.4202/app.2010.0020
Journal or Publication Title:	Acta Palaeontol. Pol.
Volume:	56
Number:	3
Page Range:	S. 615 - 640
Date:	2011
Publisher:	INST PALEOBIOLOGII PAN
Place of Publication:	WARSAW
ISSN:	1732-2421
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language METACRINUS-ROTUNDUS; RHENISH MASSIF; MIDDLE; TAXONOMY; GERMANY Multiple languages Paleontology Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48943