Hemicyclopora sp. 1

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 : 381

Hemicyclopora sp. 1

( Fig. 4 A-C; Table 4 )

MATERIAL EXAMINED. — Portugal, Azores, São Miguel Island • 1 colony; R / V Jean Charcot; Biaçores, Stn 145, 37°41’N, 25°33.5’W; 135-148 m depth; 30.X.1971; on shell; Dre; H. Zibrowius leg.; MNHN • 2 ovicellate colonies; S of São Miguel; R / V Jean Charcot; Biaçores Stn 146, 37°39.8’N, 25°35.8’W; 330-334 m depth; 30.X.1971; on scoria and biogenic concretion; Dre; H. Zibrowius leg.; MNHN-IB-2017-1558 .

DESCRIPTION

Colony encrusting, unilaminar. Autozooids quincuncially arranged, frontal shield bulged, granular, marginal pores medium-sized (18-25 µm), arranged in a single row split in two below the proximal edge of orifice; pore-chambers oval and flattened, numerous along the vertical walls. Orifice terminal, slightly longer than wide in non-ovicellate zooids, wider in ovicellate zooids, condyles prominent, triangular, proximal edge slightly concave or straight, a collar proximal to the orifice edge, low but becoming high when adjoining the proximalmost pair of spines. Oral spines eight in non-ovicellate zooids and six in ovicellate ones, with bases relatively high and thick. Ovicell vertically recumbent on a basal kenozooid, endooecium with the same granular surface as the frontal shield, proximal edge smooth with a vizor more or less high. Occasional occurrence of interzooidal kenozooids with porous shield. Ancestrula with 12 spines, five of which around the opesia, cryptocyst finely granular, peripheral and proximal gymnocyst widely extended.

REMARKS

These Azorean specimens are close to H. neatonensis n. sp. Their common traits include the granular surface of the bulged frontal shield, the shape of the orifice area including the primary orifice with prominent triangular condyles, a slightly concave proximal edge (poster), the number of oral spines (eight in non-ovicellate zooids and six in ovicellate ones), a low, arched crest below the poster, which is attached to the base of the most proximal spines, the structure of the ovicell, produced by a basal kenozooid, with a vizor above the orifice edge ( Fig. 4A, B ), the presence of interzooidal kenozooids ( Fig. 4A ), and a similarly-shaped ancestrula with 12 spines ( Fig. 4C ). Apparent differences with H. neatonensis n. sp. concern mainly the length and width of autozooids, which are larger, while ovicells are narrower ( Table 1 ), less swollen, with a vizor which is differently shaped and sized. However, this comparison is based on only three Azorean colonies. These colonies were compared to unpublished SEM photos of another specimen from the Azores collected in a locality close to those of Hemicyclopora sp. 1 (R/V Jean Charcot, Biaçores 1971, Stn 167, 130 m, 37°46’0”N, 25°48’8”W; JGH leg.). This specimen differs clearly from the latter in having ovicellate and non-ovicellate zooids with six oral spines in most cases, an orifice with a concave proximal edge, bordered by a very high, arched collar, and ovicells bearing an erect, highly prominent vizor. These features resemble H. canalifera , which, therefore, would co-occur with Hemicyclopora sp. 1 .

The clarification of the “ multispinata ” species complex would require detailed morphological and genetic analyses of new material from Madeira with features similar to those of Busk’s type, and compared with other material from the Atlantic, including the Azores, and from the Mediterranean ( H. neatonensis n. sp.).

Figures

FIG. 4. — Hemicyclopora sp. 1: A, lateral view of ovicellate and non-ovicellate zooids with granular frontal shield, marginal pores and basal pore chambers, note the structure of the orifices and the ovicells with vizor, recumbent on a basal kenozooid; B, frontal view of an ovicellate zooid with typical features; C, ancestrula with 12 spines. Origin: Azores; Biaçores Stn 145-146; MNHN-IB-2017-1558. Scale bars: A, B, 200 µm; C, 100 µm.