New discoveries of echinoderms from the Devonian-Carboniferous boundary interval from the Lesní lom quarry in Brno-LíšeňArticle PDF
New discoveries of echinoderms from the Devonian-Carboniferous boundary interval from the Lesní lom quarry in Brno-Líšeň
This research was focused on eleutherozoid (vagil, non-pelmatozoan) echinoderms of the uppermost Devonian (Famennian) from the Lesní lom quarry in the Moravian karst. A large number of previously documented crinoid columnae, and vertebrae of eospondyloid and furcasteroid ophiuroids (brittle stars) along with elements of pharyngeal ring of holothuroid (sea cucumbers) of the genus Achistrum were found in insoluble residues from the limestone of the last Famennian conodont zone Protognathodus kockeli. Currently documented sclerites of ophiuroids are lateral plates of furcasteroids and the columnar spine with unknown ophiuroid affinity. Furthermore, echinoids were common, especially elements of thein trivalve globiferous pedicellaria and demipyramids from the Aristotle’s lantern (?genus Albertechinus) were documented for the first time from the studied area. The abundant presence of goniatites and limestone fabric (lime mudstone, wackestone to floatstone) indicates pelagic depositional setting of the limestone nodules in which studied echinoderms occur. The described association of echinoderms, as well as accompanying low-diversity conodonts and macrofossils, is considered as opportunistic association, which appeared after the main extinction and regression events of the Hangenberg Crisis.