- Tytuł:
- Revision of the flexible crinoid genus Ammonicrinus and a new hypothesis on its life mode
- Autorzy:
- Bohaty, J.
- Powiązania:
- https://bibliotekanauki.pl/articles/20333.pdf
- Data publikacji:
- 2011
- Wydawca:
- Polska Akademia Nauk. Instytut Paleobiologii PAN
- Tematy:
-
flexible crinoid
crinoid
Ammonicrinus
new hypothesis
life mode
Crinoidea
Flexibilia
Devonian
Eifelian
Rhenish Massif
Germany
paleontology
Middle Devonian - Opis:
- 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.
- Źródło:
-
Acta Palaeontologica Polonica; 2011, 56, 3
0567-7920 - Pojawia się w:
- Acta Palaeontologica Polonica
- Dostawca treści:
- Biblioteka Nauki
Artykuł