A brief review of seagrass-associated bryozoans, Recent and fossil.

Information concerning fossil and modern bryozoan assemblages reported from seagrass habitats is scattered through a large number of papers. The current paper groups taxonomically data from the literature on both modern and fossil bryozoans associated with seagrasses. Most of the modern data comes from studies focused on Posidonia oceanica meadows inhabiting the Mediterranean Sea, where a total of 152 bryozoan species have been recorded. Forty-one species have been reported on seagrasses from other geographical areas, such as Saudi Arabia, tropical America, Japan and Australia. Differences are outlined between the well-delineated communities of the leaves and the rhizomes, and some generalizations are made about morphological strategies for living as seagrass epiphytes. Seagrasses are seldom fossilized but examples of ancient communities can be inferred from the presence of bioimmurations of seagrass surfaces and from associated biota. They include a single Cretaceous community from the Maastrichtian of The Netherlands (43 bryozoan species), and a few Cenozoic communities described from several geographical regions (e.g. Europe, tropical America, Indo-Pacific; 72 species). New data is reported from a dark grey, silty clay in the Miocene of East Kalimantan (Indonesia) where the presence of the seagrass-indicative gastropod Smaragdia allows interpretation of the palaeoenvironment as a seagrass meadow with associated corals. The bryozoan assemblage here is monogeneric, comprising two species of Vincularia.