Two enigmatic bryozoans from the Middle Ordovician of the East Baltic

摘要

Two rare, poorly known bryozoan genera from the Middle Ordovician (Volkhovian-Lasnamagian) of the St Petersburg Region, north-west Russia, are revised and redescribed based on new finds. Hexaporites fungiformis Eichwald, 1860 is redefined as the type species of the genus, which is shown to be one of the earliest representatives of the suborder Halloporina. The bryozoan nature of the specimen described and illustrated by Eichwald as Nebulipora ovulum is confirmed after re-study of a single preserved specimen. However, the original concept of this binomen was more likely to have been based on a Silurian heliolitide coral. Therefore, the name Eichwaldipora ovulum gen. et sp. nov. is introduced.