Unveiling the cheilostome bryozoan fauna of Daidokutsu submarine cave (Okinawa, Japan) over the last 7,000 years

The study of marine bryozoans in Japan dates to the late 1800s, with research primarily focusing on Pleistocene and Recent faunas in shallow-water shelf habitats. This paper aims to address gaps in the study of Holocene bryozoan assemblages from cave habitats in Japan by examining the cheilostome bryozoan fauna of a sediment core (Core 19) spanning the last 7,000 years extracted from Daidokutsu cave, a submarine cave on Ie Island, Okinawa. The study describes and illustrates using scanning electron microscopy, 63 cheilostome bryozoan species, comprising 17 anascan-grade and 46 ascophoran-grade cheilostomes, and introduces three new genera and 30 new species, a significant proportion consistent with previous studies on other Japanese bryozoan faunas. Additionally, we transfer the family Crepidacanthidae from Mamilloporoidea to Adeonoidea. This research establishes a critical taxonomic foundation for future ecological studies aimed at understanding the responses of the bryozoan community in this cave habitat to environmental and climate changes through the Holocene. The inclusion of bryozoan data expands the multi-taxon approach that was previously focused on other groups of organisms (ostracods, molluscs, foraminifera), thus providing a more comprehensive understanding of the historical biodiversity and ecological dynamics of the region.