Upper Maastrichtian and Danian bryozoans from Northern Patagonia, Argentina

ABSTRACT The specimen-rich and diverse bryozoan fauna encrusting oyster shells from the Maastrichtian and Danian Jaguel and Roca formations in the Neuquen Basin (Patagonia, Argentina) is described. Thirteen cyclostome species are recorded, along with 18 cheilostomes. We introduce two new species: Akatopora kaufmanni sp. nov. and Eoporella lunata gen. et sp. nov. The latter is a homeomorph of the common Miocene–Recent genus Microporella. Ten of the cyclostomes and ten of the cheilostomes could not be identified at species-level because of preservational limitations or lack of diagnostic characters in the available specimens. The most common bryozoans present are sheet-like colonies, among which the ascophoran cheilostome Balantiostoma is particularly well represented. Results show that in northern Patagonia the diversity of encrusting bryozoans associated with oyster shells exhibits no major changes across the K/Pg boundary. However, an important increase in the diversity is recorded during the upper Danian.