Hemicyclopora sp. 2

Harmelin, Jean-Georges & Rosso, Antonietta, 2023, On some “ Hemicyclopora ” Norman, 1894 and “ Escharella ” Gray, 1848 species (Bryozoa, Cheilostomatida) from the Atlantic-Mediterranean region. Re-examination of their generic status and description of new species and a new genus, Zoosystema 45 (10), pp. 373-407 : 397-398

Hemicyclopora sp. 2

( Figs 13 A-C; Tables 1 ; 4 )

MATERIAL EXAMINED. — Spain. N Iberian Peninsula • 1 living ovicellate colony (30 autozooids, 3 ovicells); R / V Thalassa ; Stn X301; Asturias; 44°07.7’N, 05°09.4’W; 980-1020 m depth; 12.X.1971; on D. pertusum ; Dre; H. Zibrowius leg.; MNHN-IB-2017-1559.

DESCRIPTION

Colony encrusting, unilaminar. Autozooids quincuncially arranged, roughly hexagonal, large (L ≥ 1 mm, Table 1 ), some peripheral zooids nearly triangular due to a considerable proximal widening ( Fig. 13A ); frontal shield bulged, remarkably high at the level of the orifice ( Fig. 13B ). Orifice sub-terminal, longer than wide (ratio L/W up to 1.3); proximal edge straight or very slightly concave, without umbo or lower thickening; condyles prominent, triangular ( Fig. 13C ). Oral spines eight in non-ovicellate zooids, six in ovicellate ones. Ovicell cleithral, distinctly attached to the distal wall of the maternal zooid, likely associated to a basal kenozooid, rather flattened and wide ( Fig. 13B, C ), with a low mucro above the proximal edge.

REMARKS

This single, small colony most likely belongs to an undescribed species, but its peculiarities need to be verified and precised on more abundant material before introducing a new species name. It differs from the other Hemicyclopora first by the combination of obviously visible characters: large size and particular shape of zooids, shape of the orifice, type and shape of the ovicell. Small characters were not visible on this colony left uncleaned and not observed with SEM. It is probably an exclusively deep-water species, perhaps preferentially associated to the community of cold-water scleractinians.

Figures

FIG. 13. — Hemicyclopora sp. 2: A, colony on a fragment of coral skeleton; B, same colony, zooids showing a typical profile with a great distal thickness, a terminal orifice, a vertical distal wall, and a terminal, highly recumbent ovicell; C, frontal view of non-ovicellate and ovicellate zooids. Origin: Asturias, Thalassa X301; MNHN-IB-2017-1559. Scale bars: A, 1 mm; B, C, 400 µm.