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Fossil echinoderms are a rich source of information concerning biotic interactions. In this study we analyzed the premortem encrustation of the highly specialized Middle Devonian rugose coralsAspasmophyllum crinophilumand ?“Adradosia” sp. on camerate crinoid stems.Aspasmophylluminfested living crinoid stems by sclerenchymal outgrowth that formed a skeletal ring but ?“Adradosia” sp. encrusted the stems rapidly, without building a ring. These coral-crinoid biocoenoses indicate a settlement advantage for the rugose corals within densely populated communities of the lower Givetian. The corals could be interpreted as large epizoozoans that benefited as secondary tierers reaching relatively high tiering levels. It also suggests the ability for the affected crinoids to repel the coral by overgrowing the corallite with a local increased stereomic growth. Because the crinoid axial canals are not penetrated, the corals cannot be considered as predators or parasites of crinoids. Therefore, the described biocoenosis is interpreted as commensalism. The speciesA. crinophilumis redescribed, and a neotype is defined, because of the loss of the initial types. Two types of ichnofossils can be attributed to the premortem encrustation of both corals. They are described asOstiocavichnusn. ichnogen. and are attributed to the stereomic response of the infested hosts. These swellings are characterized as either elliptical (Ostiocavichnus ovalisn. ichnogen. n. ichnosp. due to the assumed reaction ofA. crinophilum) or subcircular concavities (O. rotundatusn. ichnogen. n. ichnosp. due to the reaction of ?“Adradosiasp.”).

The discovery of new specimens and restudy of known collections resulted in revision of some members of the cladid crinoid family Cupressocrinitidae. “Cupressocrinites gracilis” is generically separated from Cupressocrinites whereby “Procupressocrinus” is resurrected from synonomy and assigned to the Cupressocrinitidae with C. gracilis Goldfuss, 1831 as the type species. Studies of the Sandberger collection presuppose the revision of “Abbreviatocrinites abbreviates altus” (=A. altus n. comb.) and A. nodosus. Furthermore, the hitherto undetermined cupressocrinitids are described as Cupressocrinites ahuettensis n. sp. and Robustocrinites cataphractus n. sp. The event-controlled distribution of Robustocrinites is discussed and shows similarities to other crinoid genera within the Eifel region. Observed arm-regeneration in Robustocrinites, as well as the postmortem incurred ossicular-boring of an indeterminable organism and the skeletal-colonization by a trepostome bryozoan, are further observations of other pre- and postmortem ossicular modifications in cupressocrinitid skeletons.

Es wird hier als ,,Schlade-Event'' eingeführt und als Höhe-punkt des transgressiven Unteren pumilio-Events betrachtet. Die niedrig-diverse, vagile epibenthische EchinodermenFauna wird als post-Disaster-Fauna interpretiert, welche gemeinsam mit dem spezialisierten Trilobiten Goldius den dysaeroben, weitgehend wassergesättigten Weichboden wiederbesiedelte. Aus dem Hangenden (obere Büchel-Formation) des nahe gelegenen, aufgelassenen ,,Steinbruch Zimmermann'' stammen die Cupressocrinitiden Halocrinites und Procupressocrinus. Die Crinoiden siedelten gemeinsam mit entsprechend adaptierten Brachiopoden (Uncites, Stringocephalus) and Bivalven (Eomegalodon) im hochenergetischen Habitat eines Reef-Flats und wurden durch Stürme in Reef Flat-Pools eingeschwemmt. In diesen außergewöhnlichen, mergelgefüllten Verschüttungslager-stätten sind sie parautochthon gemeinsam mit einer autochthonen, überwiegend aus Gastropoden bestehenden Fauna und extrem seltenen allochthonen Organismen des offenen Meeres erhalten. Die publizierten Biozonierungen der Büchel-Formation, insbesondere die AmmonoideenSukzession, werden evaluiert, teilweise korrigiert und durch ökostratigraphische Rugosen-und Crinoiden-Assoziationen ergänzt. Schlade-Event und folgendes Taghanic-Event sind wesentliche Kontrollfaktoren für die Biozonierung. Im systematischen Teil werden die aus dem Schlade-Tal bekannten Holothurien revidiert sowie die Taxonomie der Ophiocistioiden und Crinoiden diskutiert. Sämtliche vormals ''Abbreviatocrinites'' zugeordnete Arten werden der Gattung Halocrinites zugewiesen, welche Priorität besitzt.Schlü sselwörter Devon Á Rheinisches Schiefergebirge Á Echinodermata Á Biostratigraphische Korrelation Á Fossillagerstätten Á Lower pumilio-Event Á Taghanic-Event