Crisia fragosa, Ramalho, Muricy & Taylor, 2009

Ramalho, L. V., Muricy, G. & Taylor, P. D., 2009, Cyclostomata (Bryozoa, Stenolaemata) from Rio de Janeiro State, Brazil, Zootaxa 2057, pp. 32-52 : 38-39

Crisia fragosa sp. nov.

( Fig. 4A–D)

Material examined. Type material. MNRJ-184 (holotype), MNRJ-239 (paratype), hull of the ship Valentin Shashin, Macaé, Bacia de Campos , Rio de Janeiro State, 14 December 2002, collector J.E.A. Gonçalves, depth 3 m.

Comparative material. Crisia eburnea: NHM 99.7.1.3913; Crisia elongata: NHM 79.4.25.73; Crisia ramosa : paratype: NHM 1900.6.26.12, August, 1889, Plymouth; Crisia kerguelensis : holotype: NHM 99.7.1.3951; Crisia acropor : holotype: NHM 1977.5.2.4 (Hayward & Ryland, 1978, fig. 6); Crisia conferta: NHM 1936.12.30.156; Crisia denticulata : syntype: NHM 26.10.1.1, Cabo Verde Island; Crisia eburneadenticulata: NHM 99.7.2.3902.

Diagnosis. Colony arborescent, up to 2 cm high, white. Internodes formed by 6–11 autozooids alternately disposed to left and right; well developed peristome, directed slightly outwards and upwards; aperture circular; new internodes usually formed immediately above third autozooid of a parental internode; gonozooid pear-shaped, elongate, ooeciostome well developed, ooeciopore circular. Pseudopores slit-shaped, more densely distributed on gonozooids, including ooeciostome.

Description. Colony white, arborescent, jointed, up to 2 cm high ( Fig. 4A). Internodes 1358–(2053)–2716 µm long x 145–(162)–194 µm maximum width and 78–(87)–97 µm minimum width, formed by 7–11 autozooids alternately disposed on sterile branches, and by 6–7 autozooids on fertile branches. Joints pale in colour, yellowish or beige. New internodes usually originate laterally above third autozooid but sometimes from first position ( Fig. 4A, B). Autozooids 863–(976)–1212 µm long x 78–(91)–97 µm wide, with long peristomes slightly distally curved, facing outwards or upwards; distance between neighbouring peristomes 359–(594)–873 µm; exterior wall with slit-shaped pseudopores. Rhizoids present. Gonozooids pear-shaped, elongate, 630–(710)–757 µm long x 339–(349)–359 µm wide, occupying position of fourth zooid on internode; ooeciostome flared, located distally near edge of branch, slightly curved towards frontal surface ( Fig. 4C); ooeciopore circular, wide, 68–(78)–87 µm in diameter; pseudopores numerous on gonozooid frontal wall and ooeciostome, internally circular but externally slit-like ( Fig. 4D).

Etymology. The name fragosa refers to the fragility of the colonies.

Remarks. Five species of Crisia have been recorded from Brazil: C. pseudosolena ( Marcus, 1937) (see above), C. ramosa Harmer, 1891 , C. micra Marcus, 1955 , C. ficulnea Buge, 1979 , and C. holdsworthi Busk, 1875 . Of these, C. ficulnea and C. pseudosolena lack ooeciostomes.

The new species from Rio de Janeiro differs from C. micra which has an abruptly dilated gonozooid, and lacks pseudopores on the distal part of the gonozooid and the ooeciostome. The measurements given by Marcus (1955) also differ, usually being smaller. Crisia ramosa has internodes with a greater number of autozooids (22 on the sterile and 29 on the fertile branches), lacks curvature of the ooeciostome and has circular pseudopores. Crisia holdsworthii has 9–11 autozooids per internode, shorter peristomes which are normally turned to the front, and new branches that arise from the position of the second or third autozooid.

Crisia kerguelensis Busk, 1876 seems to be the most similar species to C. fragosa sp. nov., with which it shares a similar number of autozooids per internode and has similarly shaped colonies and gonozooids. However, it has some characteristics that differ from the new species: smaller internodes (1420–1980 µm), larger gonozooids (length 1030 µm) and ooeciopore (diameter 110 µm) and pseudopores of a different shape (rounded oval). Although C. eburnea ( Linnaeus, 1758) has a similar number of autozooids per internode, it differs from the new species as bifurcations occur at the position of the first autozooid of the internode and the gonozooid arises on the second or third autozooid and has a short ooeciostome. The autozooids are also shorter. Crisia carolina Winston, 2005 also has a similar number of autozooids per internode (7–9), but it differs from the new species in having dark brown to black joints, shorter peristomes turned to the front and short ooeciostomes. Crisia irregularis Borg, 1944 has internodes with fewer autozooids (three to five in sterile and six to eight in the fertile internodes), gonozooids that have a very different shape, short ooeciostomes bent to the front, and transversely oval ooeciopores.

Whereas Crisia sinclarensis Busk, 1875 has a similar number of autozooids per internode to C. fragosa sp. nov., free parts of the autozooids are shorter and have denticles on their lateral distal borders. In addition, new internodes arise from the first autozooid of the parental internode.

Globally, the majority of Crisia species have internodes formed by a greater number of autozooids than those in C. fragosa sp. nov., e.g. C. elongata Milne Edwards, 1838 , C. zanzibarensis Brood, 1976 , C. bifurcata Brood, 1976 , C. transversata Brood, 1976 , and C. patagonica d’Orbigny, 1839 .

Ecology. Colonies were found on the hull of a ship at 3 m depth.

Geographic distribution. Macaé (Bacia de Campos), Rio de Janeiro State, Brazil.