Bryozoan-Hydroid Symbiosis and a New Ichnogenus, Caupokeras

Several genera of modern cheilostome bryozoans are hosts of epibiotic zancleid hydroids that have a diversity of host-guest relationships that in general are mutualistic, although a cost of the relationship may involve some degree of parasitism of the bryozoan by the hydroid. The modern host bryozoans typically grow skeletal tubes that enclose the stolon system of the epibiotic zancleids, producing preservable structures. Devonian fenestrate bryozoans secreted skeletal enclosures for modular systems of curved, distally expanding, distolaterally budding tubes generated by a soft-bodied colonial epibiont. Since the size and morphology of these tubes are similar to that of extant hydroids, they are inferred to represent a symbiotic relationship between host fenestrate bryozoans and the epibiotic hydroids and are here named Caupokeras calyptos n. igen. n. isp.