Acta Palaeontologica Polonica

Genus Ammonicrinus (Crinoidea) from the Middle Devonian of the Holy Cross Mts (Poland)

Andrzej Piotrowski

Acta Palaeontologica Polonica 22 (2), 1977: 205-218

Crinoid genus Ammonicrinus is represented by two species, A. sulcatus Kongiel and A. kongieli sp.n., in the Grzegorzowice - Skały and Świętomarz - Śniadka profiles of the Middle Devonian in the Holy Cross Mts. The presence of barre-like columnals of a limited mobility in distal part of stems and the development of wide tuberculated external cover indicate that both species represent sessile benthos. In A. sulcatus stem was connected with crown through modified columnalium. The crown was equipped with short arms which could take food in a space limited to the interior of coiled part of the stem. The food was supplied by current parallel to the bottom. The structure of crown and stem suggests that all Ammonicrinus species represent the same evolutionary stage.

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