Scrupocellaria prolata, Tilbrook, Kevin J. & Vieira, Leandro M., 2012

Tilbrook, Kevin J. & Vieira, Leandro M., 2012, Scrupocellaria (Bryozoa: Cheilostomata) from the Queensland coast, with the description of three new species, Zootaxa 3528, pp. 29-48 : 42-45

Scrupocellaria prolata n. sp.

( Figure 10 )

Material examined. Holotype (here selected): MTQ G25341, Site 813, Sample Id 0 0 0 125, SBD 0 0 1581, Great Barrier Reef, 18.635° S, 147.275° E, 18 September 2003.

Description. Autozooids at very slight angle to each other, partially back to back; gracile, 0.461–0.561 mm (0.481±0.038) long, 0.181–0.228 mm (0.196±0.018) wide, with smooth, proximal gymnocyst, approximately one third area of opesia, cryptocyst very narrow and smooth around the elongate oval opesia. Scutum often present, originating from midway along inner (branch midline) lateral margin of opesia, most often rounded, almost triangular, concave, with symmetrical lobes. Two inner orificial spines and two outer orificial spines, short, the most proximal of each distorting the opesial rim, directed frontally and bifurcating, a fifth distomedial spine in nonbrooding and axial autozooids. Avicularia of two types: lateral avicularium small, on distolateral corner of each autozooid adjacent to proximalmost outer spine, laterally directed, with triangular rostrum, mandible curved basally with an acuminate, hooked tip; frontal avicularium often seen, originating proximal to cryptocystal rim on inner side of zooids, directed frontolaterally, large, of varying size, aquiline, raised on a small tubular base, with elongate triangular rostrum serrated laterally, with a hooked tip, mandible elongate-triangular, curved basally with an acuminate, hooked tip. Ovicells subglobular, 0.124–0.144 mm (0.138±0.007) long, 0.177–0.215 mm (0.187±0.013) wide, smooth with approximately six circular or elongate oval pores each with a slightly raised rim, a discernible thickened ridge around ovicell opening. Single axial vibraculum; other vibracula projecting laterally, 0.170–0.211 mm (0.189±0.011) long, visible frontally, drop-shaped, slit-like setal groove directed proximomedially, setae long, curving across more than width of branch. A rhizoid foramen is present in proximal wall of all lateral vibracula, but not on axial vibraculum; rhizoids present distal to each branch bifurcation along length of branch.

Etymology. Latin, prolatus, extended, elongated. Named for the shape of the frontal avicularia.

Remarks. Scrupocellaria prolata n. sp. is characterised by the shape of its rounded, almost triangular, concave scutum, the frontally directed, elongate triangular frontal avicularia, and the ovicells with a thickened edge to their opening.

Scrupocellaria prolata n. sp. is most similar to S. diadema and S. cervicornis ; they share the production of bifurcating proximal spines and ovicells with pores that have a slightly raised rim, however, S. prolata n. sp. differs by producing frontally directed elongate frontal avicularia and larger zooids than those of S. diadema and S. cervicornis .

Distribution. Scrupocellaria prolata n. sp. has not been recorded previously and is known only from a single specimen.

Figures

FIGURE 10. Scrupocellaria prolata n. sp. A – D, MTQ G 25341. A, frontal surface of branch with ovicellate zooids. B, frontal surface of ovicellate autozooids; note the bifurcating distolateral spines, triangular scuta, and the ovicells with the thickened proximal edge to their openings. C, frontal surface at branch bifurcation of older part of colony, with rhizoids. D, basal surface of branch bifurcations surface showing axial and lateral vibracular chambers; note the two rhizoids with substratum attachment points intact. Scale bars: 500 µm (A, C, D); 100 µm (B).