Lower Kimmeridgian comatulid crinoids of the Holy Cross Mountains, Central Poland

Urszula Radwańska

Abstract


An assemblage of feather stars or comatulids (free-living crinoids of the order Comatulida AH. CLARK, 1908) is reported for the first time from Upper Jurassic sequences of Poland, precisely from Lower Kimmeridgian strata of the Holy Cross Mountains. The major part of this assemblage comes from oolitic deposits exposed at Malogoszcz Quarry, others from oyster (Actinostreon, and Nanogyra) shellbeds higher up section at Małogoszcz, as well as from the coeval strata of the Karsy section. Taxonomically recognizable skeleton elements such as calyces, isolated eentrodorsals and radials are here assigned to seven taxa, three of which are new to science: Comatulina malogoslialla sp.nov., Palaeocomaster learsensis sp.nov., and Solanocrinites sanctacruccnsis sp.nov. The majority of the material available was contained in burrows made by some ancestral stock of alpheid shrimp, closely comparable to those of present-day snapping shrimp (genus Alpheus WEBER, 1795), and its allies. These burrows, situated at the tops of oolitic shoals/banks at Małogoszcz, casually served both as habitats of cryptic faunas (mostly comatulids, dwarf-sized gastropods) and as preservational/taphonomic traps for others, primarily echinoderms (ten taxa of echinoids, three stalked crinoids, two ophiuroids, one asteroid) swept into by highly agitated waters, most likely during storms, to produce an Echinodermenlagerstdlte. Comatulid remains from the oyster shellbeds undelwent longer periods of transport, to be entombed far from their habitats.


Keywords


Crinoidea, Comatulida, Taxonomy, New Species, Eco-taphonomy, Upper Jurassic, Poland

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