AN UNREPORTED INVASIVE BRYOZOAN THAT CAN AFFECT LIVELIHOODS - MEMBRANIPOROPSIS TUBIGERA IN NEW ZEALAND AND BRAZIL

摘要

Membraniporopsis tubigerum (Osburn, 1940) (Cheilostomata) is added to the list of known invasive bryozoans. Originally described from Puerto Rico, Texas, and Florida, it has been found at several localities in southern Brazil since October 1997 and in Kaipara Harbour, New Zealand since December 2001. At the latter location, its irruption in the austral summer-autumn of 2001-02 resulted in such massive numbers of erect colony fragments as to clog set nets for flounder and wash up on local beaches in stinking 20-cm-thick drifts. Since then, its frequency of occurrence has declined and it was not definitely seen in the harbor in 2003 and 2004. Neither the manner of reproduction nor agency of dispersal is known. It is even possible that the original description may have been based on invasive material inasmuch as the only certain congeners, Membraniporopsis bifloris (Wang and Tung, 1976) and Membraniporopsis serrilamelloides (Liu and Li, 1987) are east Asian species. New characters are identified that are diagnostic of the genus Membraniporopsis, which is provisionally included in the Flustridae in the absence of knowledge about larval type. A full redescription of M. tubigera is provided, along with information on skeletal mineralogy; it is noted that M. tubigera has exceptionally high-magnesium calcite.