Simakocrinus gen. nov. (Crinoidea, col.) from the Bohemian Early and Middle Devonian of the Barrandian Area (the Czech Republic)

“…Unlike brachiopods (Havlíček 1956, Havlíček & Vaněk 1998, gastropods (Horný 1955, 1963, 1964, Frýda 1998, 1999a, 1999b, Frýda & Bandel 1997, annelids (Prokop 2002), eleutherozoans (Prokop 1993, Prokop & Petr 1986, Hotchkiss et al 1999a, 1999b, 2007, pelmatozoan columnals (Slámová & Prokop 2000, Prokop & Slámová 2008, 2012, Prokop 2009, 2013, Prokop & Nohejlová 2015, crinoid crowns and calyxes (Prokop 1969, 1970, 1980, 1982a, 1982b, 1986, 1997, Prokop & Petr 1987, 1988, 1991, 1993, 2010 or other pelmatozoan ossicles (Prokop & Petr 2002, 2004, the crinoid holdfasts were only briefly mentioned among washed fossils of white beds (Petr 1983, Galle & Prokop 2000. Like the other shells, crinoid holdfasts and small epibiots attached to crinoid columnals and stems are excellently preserved.…”

Section: Introductionmentioning

confidence: 99%

Diminutive Epibionts on Crinoid Stems from the Lower/Middle Devonian Boundary in the Barrandian, Czech Republic

Mergl

Šmídtová

2022

Folia Musei Rerum Naturalium Bohemiae Occidentalis. Geologica Et Paleobiologica

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Diminutive crinoid holdfasts and cemented tests of the foraminifers Psammosphaera and Tolypammina were observed on coarse bioclasts in weathered limestones of the Daleje-Třebotov Formation. Specimens were obtained in 1984 by washing so called “white beds” at a temporary locality in Praha- Barrandov. A few millimeter sized bioclasts with epibionts were freed from hard limestone beds of the Třebotov Limestone near the Lower/Middle Devonian boundary by long-term weathering. Many of the crinoid holdfasts attached to pluricolumnals provoked a stereomic response of the host crinoid. Also the growth orientation of the crinoid epibiont is not random and indicates some crinoid-epibiont to crinoidhost interaction. Reaction of host stereome and non-random stem orientation offer direct evidence of epibiont larval settlement and subsequent growth on the stem of a living crinoid host. The extensive growth of the host stereome ended by partial to total engulfing of the epibiont holdfast. This indicates advancing and finally successful defence of the host crinoid against the epibiont. The holdfast gives evidence that the small host crinoids offered a somewhat higher tier for even smaller epibiont crinoids. However, other observed holdfasts indicate fixation of larva and growth over loose bioclasts lying on a sea bed. Location of foraminifer test on bioclasts confims that foraminifers cemented and grew on loose echinodermal and brachiopod remains and preferred crevices and similar protected sites with concave profiles. This is clear evidence that diverse bioclasts (brachiopod shells, pelmatozoan ossicles) provided the hard substrate suitable for epibiont life on a sea bed.

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Two Coils in the Morphology of Myelodactylids (Crinoidea, Disparida): the Morphogenetic Basis of Their Formation and Adaptation Potential

Рожнов

2021

Paleontol. J.

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Simakocrinus gen. nov. (Crinoidea, col.) from the Bohemian Early and Middle Devonian of the Barrandian Area (the Czech Republic)

Cited by 4 publications

References 4 publications

Thecal cup of the crinoid Edriocrinus preserved inside the shell of an orthocone cephalopod: Middle Devonian, (Eifelian) from Bohemia

Thecal cup of the crinoid Edriocrinus preserved inside the shell of an orthocone cephalopod: Middle Devonian, (Eifelian) from Bohemia

Diminutive Epibionts on Crinoid Stems from the Lower/Middle Devonian Boundary in the Barrandian, Czech Republic

Two Coils in the Morphology of Myelodactylids (Crinoidea, Disparida): the Morphogenetic Basis of Their Formation and Adaptation Potential

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