Trophic partitioning and feeding capacity in Permian bryozoan faunas of Gondwana

Bryozoans are epibenthic suspension-feeders and use their ciliated tentacles to generate feeding currents. Modern bryozoan mouth size limits the size of the particles that can be ingested, and lophophore diameter is linked to water pumping rates. In fossil bryozoans these soft parts are absent, however, mouth and lophophore dimensions can be inferred from preserved skeletons. Gondwanan Permian palaeostomate bryozoans show distinct order-level trophic partitioning across warm to cold-water faunas. In diverse warm-water faunas of southern Thailand fenestrate bryozoans consume the smallest food particles, cryptostomes and trepostomes consume mid-size particles, and cystoporates consume the largest, and widest range, of particles. In contrast, in low diversity cold-water faunas of eastern Australia, where cystoporates and cryptostomes are uncommon, fenestrate bryozoans again consume the smallest food particles, however the abundant trepostomes have much larger mouths than their warm-water c...