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The first record record of the comatulid crinoid Sievertsella Radwańska, 2003 and its implications for the Miocene of the Bragança-Viseu Basin, Brazil

De Castro Manso C. L., Souza-Lima W.

Acta Geologica Polonica

2017

Vol. 67, no. 3

425--432

The first record of a comatulid crinoid Sievertsella cf. polonica (Radwańska, 1987), from the Pirabas Formation (Miocene of NE Brazil) is documented. The record points out to a shallow coastal tropical or subtropical paleoecosystem with rocks or reefs in the Miocene from Bragança-Viseu Basin on Brazilian equatorial margin.

A rare comatulid crinoid, Semiometra petitclerci (CAILLET, 1923), from the Upper Oxfordian of Poland

Radwańska U.

Acta Geologica Polonica

2007

Vol. 57, no. 2

161-167

A small faunule of feather stars or comatulids (free-living crinoids of the order Comatulida A.H. CLARK, 1908) is recorded from Upper Oxfordian strata (Bielawy/Wapienno sequence) in the Couiavia region, north-western Central Poland. It represents a single, very small-sized species, Semiometra petitclerci (CAILLET, 1923), hitherto an extreme rarity in the Jurassic sequences of France and Germany. The present record extends the geographic distribution of the species in Europe, to evidence a wider range of the genus Semiometra GISLEN, 1924, prior to its fairly common occurrence and higher diversity during the Late Cretaceous.

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

Radwańska U.

Acta Geologica Polonica

2005

Vol. 55, no. 3

269-282

An assemblage of feather stars or comatulids (free-living crinoids of the order Comatulida A.H. 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 Małogoszcz 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 centrodorsals and radials are here assigned to seven taxa, three of which are new to science: Comatulina malogostiana sp.nov., Palaeocomaster karsensis sp.nov., and Solanocrinites sanctacrucensis 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 Echinodermenlagerstńtte. Comatulid remains from the oyster shellbeds underwent longer periods of transport, to be entombed far from their habitats.