Bryozoa collected by the United States Antarctic Research Program: new taxa and new records Author Hayward, Peter J. Author Winston, Judith E. text Journal of Natural History 2011 2011-10-31 45 37 - 38 2259 2338 http://dx.doi.org/10.1080/00222933.2011.574922 journal article 10.1080/00222933.2011.574922 1464-5262 5204333 Cellarinella incompta sp. nov. ( Figure 18A, B ) Material Holotype . NMNH 1154033 : SOSC 876 , station 114, 60 ◦ 30.1’ S , 46 ◦ 42.8’ W ; a single damaged colony, 80 mm high, with horizontal spread 90 mm . Paratype : VMNH 13665.00, same data as Holotype . Description Colony erect, attached by an encrusting base, developed as a short, thick peduncle, 8 mm diameter, 10 mm high, above which it expands into a rigid, folded, bilaminar plate, 2 mm thick at growing edge, 3 mm just above peduncle; colony architecture incompletely known but evidently very irregular, the folded plate has a continuous, wavy growing edge, and shows growth bands, but at points of damage it displays short, narrow, regenerating lobes. Autozooids arranged in alternating longitudinal series; individual boundaries visible only at the growing edge, reticulate calcification originating around the single series of marginal pores in the frontal shield advances centripetally, and thickens within one or two ontogenetic generations from the growing edge, and the entire frontal surface of the colony is covered by a continuous reticulate layer. Secondary orifice wider than long, a frontally curving, medially convex lip within the proximal edge of the orifice imparts a slightly crescentic appearance in later ontogeny. Avicularia very sparse, and inconspicuous; cystid budded just proximal to rim of secondary orifice, but rostrum situated within it, broadly scaphoid in outline, hooked distally, slightly acute to frontal plane and directed proximo-laterally. No other type of avicularium noted. Ovicells not apparent. Figure 18. (A, B) Cellarinella incompta sp.nov. , Paratype. (A) Portion of colony; (B) detail to show two secondary orifices and an avicularium. (C,D) Cellarinella diatriaria , Paratype. (C) Secondary orifices and paired avicularia of two autozooids; (D) growing edge of branch. Scale bars: 0.5 mm (A), 0.25 mm (B, C, D). Measurements For all measurements, n = 20, mean ± SD: autozooid length (basal view) 2.21 ± 0.22 mm ; autozooid width (basal view) 0.40 ± 0.04 mm ; length secondary orifice 0.34 ± 0.03 mm ; width secondary orifice 0.15 ± 0.01 mm . Etymology Latin, incomptus : unadorned, with reference to the simple morphology of the secondary orifice. Remarks Cellarinella incompta sp. nov resembles C . latilaminata Moyano, 1974 , the only other species of the genus known to develop a colony form of folded bilaminar plates. It differs from that species in having much large zooids than C . latilaminata (1.4–1.8 by 0.5 mm ), in its sparse avicularia, lodged within the secondary orifice, and in the simple structure of the secondary orifice. The large avicularia of C . latilaminata occur on the frontal surfaces of the autozooids, proximal to the secondary orifice, which incorporates a conspicuous distal oral shelf, missing in C. incompta sp. nov. , and typically has a pronounced umbo on its proximal edge. Cellarinella latilaminata was originally described, and later reported again, from the South Orkneys, and was listed from the Ross Sea by Hayward and Taylor (1984) ; C. incompta sp. nov was collected from the vicinity of the South Orkney Islands .