Isoseculiflustra tenuis (Kluge, 1914)

provided by British Antarctic Survey

Description

Colonies of Isosecuriflustra rubefacta occur in groups of hundreds to thousands in continental shelf waters. The species is generally found with two others: Nematoflustra flagellata and Himantozoum antarcticum. It is common and abundant but often only below 20m. It is typically brown to purple with striking bands across the frond, but these are not growth lines as described in Cellarinella watersi. The bands are formed by the brood chambers which are dark when containing embryos and translucent when these are released in January. Also unlike C. watersi the flustrid species are just unilaminar, that is active zooids are only on one surface of the frond not both. There are few Antarctic bryozoans for which more is known than this species. They feed for about 10 months of the year on small phytoplankton and grow nearly continuously. The fronds are colonised by a rich variety of tiny animals, a single frond may contain representatives of >8 major groups of animals and are a good place to look for marine mites.