Calyptotheca wulguru, Sebastian & Cumming, 2016

Sebastian, Pascal & Cumming, Robyn L., 2016, Three new species of Calyptotheca (Bryozoa: Lanceoporidae) from the Great Barrier Reef, tropical Australia, Zootaxa 4079 (4), pp. 467-479 : 469-472

Calyptotheca wulguru n. sp.

( Figs 1 , 2 , Table 1)

Material examined. Holotype: MTQ G26777 , GBR lagoon, Townsville Region , 18°48.5' S, 146°50' E (coordinates approximate), 31 January 1985, 35– 43 m, coll. A. Birtles & P. Arnold.

Paratypes: All from GBR lagoon, Townsville region, all coordinates approximate, all coll. A. Birtles & P. Arnold: MTQ G26776 , 18°48.5' S, 146°50' E, 23 January 1981, 33.5 m ; MTQ G26781 , 18°53' S, 146°58' E, 24 August 1980, 26.5 m; MTQ G26778 , 19°01' S, 146°58' E, 7 August 1984, 24 m; MTQ G26779 , 18°41' S, 146°58' E, 29 January 1985, 38– 42 m; MTQ G26782 , MTQ G26783 , 18°53' S, 146°58' E, 3 August 1986, 26.5 m; MTQ G26784, 18°53' S, 146°58' E, 24 August 1980, 26 m; MTQ G26780, 18°56' S, 146°58' E, 11 August 1984, 26 m.

Etymology. Named for the Wulgurukaba people, the traditional owners of the land of Townsville region, Queensland.

Description. Colony a network of unilaminar anastomosing tubes. Zooids opening outwards, colour pale brown/cream when dried or in ethanol ( Fig. 1A, B ), becoming multilamellar with frontal budding; autozooids rectangular, sometimes irregularly polygonal (c. 0.5 x 0.3 mm; Table 1). Frontal shield flattened to slightly convex, with rounded pseudopores (average 58 per zooid), these sometimes irregularly spaced, sparse or absent proximal to orifice and/or proximally, two pseudopores sometimes sharing same pit; interzooidal boundaries marked by thin, raised, sinuous suture lines.

Primary orifice wider than long (c. 0.11 x 0.13 mm); anter rounded; lunula extending to lateral margins; poster with shallow sinus occupying about half width of proximal border; condyles large, rounded, not serrate; slight nodular thickening proximal to orifice.

Adventitious avicularia small, oval (c. 0.04 x 0.04 mm), marginal; up to five per zooid, most zooids with three, including in both distal angles; directed medially, proximomedially or distomedially, angled frontally; proximal opesia oval, rostral foramen semicircular, crossbar complete.

Vicarious avicularia uncommon; longer than autozooids (c. 0.6 vs 0.4 mm); frontal shield with regularly spaced, rounded pseudopores, absent proximal to orifice; orifice longer than wide (c. 0.37 x 0.25 mm), slightly narrower proximally, poster with wide shallow sinus occupying about half width of proximal border; condyles large, rounded, not serrate; slight nodular thickening proximal to orifice.

Ooecium subimmersed, wider than long (c. 0.3 x 0.4 mm), pseudopores of similar size and density to those of frontal shield, secondary calcification usually cormidial as indicated by Y-shaped suture lines; pronounced orificial dimorphism, ovicellate orifice wider than autozooidal orifice (c. 0.18 vs 0.13 mm); condyles rectangular, not serrate, wider than autozooidal condyles; slight nodular thickening proximal to orifice.

Remarks. Calyptotheca wulguru n. sp. is distinguished by its tubular, branch-like growth form, small, oval, marginal adventitious avicularia, vicarious avicularia and pronounced orificial dimorphism. It belongs to the C. wasinensis subgroup for its marginal adventitious avicularia and a slight nodular thickening proximal to the orifice.

Calyptotheca wulguru n. sp. is most similar to C. fossulata from Indonesia, which is the only other member of the C. wasinensis subgroup with a tubular growth form ( Harmer 1957, p. 1020). We examined SEM images of C. fossulata held at the Natural History Museum, London (NHMUK 1980.2.1.26 paratype [Halmahera Sea], NHMUK 2014a; NHMUK 1980.2.1.27 not paratype [Banda Sea], NHMUK 2014b). They differ from C. wulguru n. sp. in having much larger zooids (c. 0.8 x 0.5 vs 0.5 x 0.3 mm), primary orifice (c. 0.15 x 0.20 vs 0.11 x 0.13 mm) and adventitious avicularia (c. 0.06 x 0.07 vs 0.04 x 0.04 mm), ooecia without cormidial secondary calcification, lesspronounced orificial dimorphism (primary orifice width vs ovicellate orifice width: C. fossulata c. 0.20 vs 0.23 mm; C. wulguru c. 0.13 vs 0.19 mm), and no vicarious avicularia.

Calyptotheca conica is the only other species of the C. wasinensis subgroup that has vicarious avicularia, and it also resembles C. wulguru n. sp. in having distinct orificial dimorphism and ooecia with cormidial secondary calcification. However, the growth form of C. conica is a unilaminar hollow cone, with basal calcareous hooks, and C. conica has distinctive large, bilobed (knuckle-shaped) condyles ( Cumming & Tilbrook 2014) and a pronounced suboral umbo on ovicellate zooids.

Cumming & Tilbrook (2014) described C. wasinensis from the Gulf of Carpentaria as bilaminate and foliaceous with small zooids (c. 0.4 x 0.25 mm), a shallow sinus, small condyles, a suboral umbo that is more pronounced on ovicellate zooids, and no vicarious avicularia. C. wulguru n. sp. is distinguished from C. wasinensis by its tubular growth form, larger zooids, larger condyles, lack of suboral umbo and presence of vicarious avicularia.

Busk (1884, pl. 17, fig. 1) described and illustrated Schizoporella nivea (now Calyptotheca nivea ) with an ‘elevation’ (adventitious avicularia) at each distal angle only. Florence et al. (2007, fig. 16G–I) also noted that the Avicularia are not numerous and are restricted to the distal angles or are sometimes absent [thus differing from Hayward & Cook’s (1983, p. 65, fig. 17H) description and illustration of C. nivea with numerous adventitious avicularia distributed along the interzooidal sutures]. This inconsistency raises the possibility of more than one closely related species. Nevertheless, the consistent features of foliaceous growth form and absence of vicarious avicularia distinguishes these entities from Calyptotheca wulguru n. sp.

Calyptotheca porelliformis has one or two small oval adventitious avicularia on each side of the operculum ( Waters 1918, pl. 2, fig. 19–21), close to sutures and lateral to the orifice or often absent altogether ( Hayward & Cook 1983, fig. 17 H). It differs from C. wulguru n. sp. in its foliaceous growth form and the absence of proximal adventitious avicularia and vicarious avicularia.

Calyptotheca australis has a similar growth form to that of C. wulguru n. sp. ( Fig. 1C, D ) and is superficially similar to the naked eye, but is readily distinguished under low magnification by its elongate, triangular, medial avicularia (see Cumming & Tilbrook 2014).

Distribution. Calyptotheca wulguru n. sp. is known only from the GBR lagoon, with all colonies collected from the Townsville region, in the area between Magnetic Island and John Brewer Reef at 26– 43 m.

Figures

FIGURE 1. A, Calyptotheca wulguru n. sp., holotype (MTQ G 26777). B, Calyptotheca wulguru n. sp., paratype (MTQ G 26781). C, Calyptotheca australis, dry collection (MTQ G 26415). D, Calyptotheca australis, bleached collection (MTQ G 26415).

FIGURE 2. Calyptotheca wulguru n. sp., A – E, G, holotype (MTQ G 26777), F, paratype (MTQ G 26782): A, general view of autozooids; B, ovicellate orifice; C, ooecia; D, primary orifice; E, adventitious avicularium; F, vicarious avicuaria; G, frontal budding.