First fossil record of Atlantisina (Bryozoa) from the Gelasian of Sicily: a new piece of evidence to unravel past bryodiversity of the deep Mediterranean Sea

Atlantisina mylaensis n. sp. is described from sediments deposited in deep-water settings during the Gelasian (early Pleistocene) that presently crop out at Capo Milazzo Peninsula (NE Sicily, Mediterranean Sea). The new species belongs to a genus recently erected for eight species that presently thrive on north-eastern Atlantic seamounts. Atlantisina mylaensis n. sp. is characterised by a prominent process located proximally to the orifice and consisting of two stout and slightly diverging lateral branches that end in bifurcate tips and are separated by a deep groove leading to a U-shaped morphology in proximo-frontal view. This species extends the stratigraphic distribution of the genus at least to the early Pleistocene, when its geographical distribution included the Mediterranean and, presumably, the Atlantic. This fossil record fits well within the frame of the observed segregation of an eastern group of Atlantisina collar-bearing species and the central Atlantic group of collar-missing species, although it does not explain how the genus diversified. The species adds to the numerous taxa already known from the same bryozoan association, confirming its Atlantic biogeographic affinity and the high bryodiversity of the Capo Milazzo associations in comparison to other known fossil and present-day deep-water faunas from the Mediterranean. However, further studies are needed in order to understand tempo and mode of the changes that affected the Mediterranean deep-water bryodiversity over time