A New Hybocrinid Genus (Echinodermata, Crinoidea) from the Middle Ordovician of Ladoga Glint on the Volkhov River

The hybocrinid crinoid Trecrinus schmidti gen. et sp. nov. is described from the Middle Ordovician (Uhaku Regional Stage, Darriwilian) of the lower reaches of the Volkhov River. Three long arms in the A, D and C radii, and a low cup with a flattened base without a stem are the main characteristics of the new genus. Morphology of the new genus emphasizes the similarities and differences in the morphogenetic capabilities of the hybocrinid lineages, which simultaneously developed on the Baltica and Laurentia paleocontinents, separated from each other in Ordovician. In the pronounced tiering of the Valim benthic community, this new genus occupied the lowest bottom stage.