Celleporaria desperabilis Ryland and Hayward, 1992

Dick, Matthew H. & Grischenko, Andrei V., 2016, Rocky-intertidal cheilostome bryozoans from the vicinity of the Sesoko Biological Station, west-central Okinawa, Japan, Journal of Natural History 51 (3 - 4), pp. 141-266 : 183-186

Celleporaria desperabilis Ryland and Hayward, 1992

( Figure 13)

Celleporaria desperabilis Ryland and Hayward, 1992, p. 251 , fig. 15(e, f).

Material examined

NSMT-Te 1090 ( SES- 20), bleached, on SEM stub; NSMT-Te 1091, part of same colony as NSMT-Te 1090, dried.

Measurements

AzL, 0.48–0.80 (0.613 ± 0.084); AzW, 0.27–0.43 (0.336 ± 0.045) (n = 15, 1). OrL, 0.12–0.16 (0.136 ± 0.013); OrW, 0.14–0.17 (0.153 ± 0.010) (n = 7, 1). OvL, 0.16–0.21 (0.184 ± 0.017); OvW, 0.22–0.27 (0.243 ± 0.023) (n = 6, 1). One colony, 40 × 20 mm.

Description

Colony encrusting, sheet-like; unilaminar at margin but becoming multilaminar in interior due to frontal budding; in living colony, intermittent patches of violet-black ectocyst adhering to surface, worn away to white in most areas. Zooids near margin ( Figure 13 (a)) recumbent; variable in size and shape; delineated by groove and incision; boundaries soon becoming indistinct ( Figure 13 (d)). Frontally budded zooids in colony interior wider than those at margin, oval to circular in outline, haphazardly oriented. Frontal wall convex, irregularly coarsely granulated to tuberculate, with four to six small, round, irregularly spaced areolae along each lateral margin; with increasing calcification, areolae become enlarged and variable in size and shape. Between zooids are scattered enlarged openings ( Figure 13 (d, e)), circular or irregular in outline and bounded by a distinct rim, indicating marginal chambers of unknown function; openings occluded by ectocyst in living colony. Primary orifice ( Figure 13 (c)) broader than long; proximal margin concave, with rounded median sinus bearing narrow, tapering denticle in midline, flanked by smaller, distomedially directed denticle on each side; sinus and denticles usually symmetrical, but sometimes median denticle curved laterally; condyles lacking. With age, primary orifice becomes sunken in peristome ( Figure 13 (d)). Oral spines lacking. Early in ontogeny zooids develop suboral avicularian chamber proximal to orifice ( Figure 13 (b)), offset to one side or other; chamber bears a blunt umbonate process that can become a moderately tall, conical process with age; rostrum raised at high angle to frontal plane, usually facing laterally; mandibular portion semicircular, with blunt denticles at end; opesial portion smaller, semicircular; crossbar thin, complete. Suboral avicularian chamber flanks a distinct secondary peristomial sinus ( Figure 13 (e)). Zooids uncommonly bear a tiny, often asymmetrical, adventitious avicularium ( Figure 13 (e)) lateral or proximolateral to orifice on one or occasionally both sides; mandible shortlanceolate or semicircular; crossbar thin, complete. No other frontal or vicarious avicularia observed. Ovicells ( Figure 13 (f)) in our specimen appear to be aborted or incompletely developed, their positions indicated by a thick, vertical, faintly crenulate semicircular rim extending distal to the orifice, completely open on top. Ancestrula not observed.

Remarks

Compared to our specimen, material from the Great Barrier Reef treated in the original description has somewhat larger suboral avicularia, and the orificial denticles are stouter and more widely spaced, with the median denticle variable (quadrate or anvil-shaped, often notched or bifid, or divided into two separate, slender denticles). However, the features of the peristome, lack of spines, paucity or lack of interzooidal avicularia, and occurrence and shape of the tiny adventitious avicularia all support this identification. The original description ( Ryland and Hayward 1992) mentions large marginal pores but does not specifically mention the large, rimmed openings between zooids as seen in our material.

Occurrence

We found a single colony at the SES site. This species was previously known only from the type locality, Heron Island , Great Barrier Reef .