Cheilostomatous bryozoan Cellarinella sp.

Cellarinella bryozoans are almost exclusively found in Antarctica (fourteen of the fifteen known species) [2]. The flat branches of this cellarinellid bryozoan have strong transverse growth checks or discontinuities; these growth checks may occur at times of the year when food supply is lowest [1]. A short distance between two cellarinellid bryozoan growth checks may be due to a year in which food supply was minimal thus retarding normal growth [1]. There appears to be a delay between maximum abundance of phytoplankton in surface water (late December - January) and bryozoan growth initiation; cellarinellid bryozoans initiate growth in early winter (July) and continue growth into late winter months [1]. 81% (215 of 264) of Antarctic Cheilostomatida bryozoan species are endemic to Antarctica [1].

This Cellarinella sp. bryozoan could be among six or so species [2,3].

Bryozoans are sedentary animals that form colonies of individuals (zooids) by budding. The external skeletal walls of bryozoans are made with calcium carbonate (calcareous). Cellarinellid bryozoan zooids sit in the equivalent of a calcified box with an opening from which a feeding structure is protruded to capture small plankton; food is carried to the mouth with cilial hairs and then sucked into the stomach for digestion [1]. Sea slugs and sea spiders are their usual predators.

1: Bulletin of Marine Science 33(3):688-702, 1983; 2: Antarctic Cheilostomatous Bryozoa. PJ Hayward. Oxford : Oxford University Press, 1995; 3: PJ Hayward, personal communication, 1999

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