Calyptotheca lardil, Cumming, Robyn L. & Tilbrook, Kevin J., 2014

Cumming, Robyn L. & Tilbrook, Kevin J., 2014, Six species of Calyptotheca (Bryozoa, Cheilostomata, Lanceoporidae) from the Gulf of Carpentaria and northern Australia, with description of a new species, Zootaxa 3827 (2), pp. 147-169 : 164-165

Calyptotheca lardil n. sp.

( Figure 7 , Table 7 )

Material Examined. Holotype: MTQ G26483, Bryomol Reef, 16°26.312' S, 139°52.748' E, encrusting Adeonella , 34.5 m.

Paratypes: Bryomol Reef: MTQ G26484, same data as holotype. MTQ G26485, 16°28.819' S, 139°55.419' E, encrusting shell, 32.5 m. MTQ G26486, 16°32.658' S, 139°53.567' E, encrusting rock, 33 m. MTQ G26487, 16°26.721' S, 139°54.028' E, encrusting shell, 33.5 m. MTQ G26488, 16°26.721' S, 139°54.028' E, encrusting Adeonella , 33.5 m. MTQ G26489, 16°28.929' S, 139°54.34' S, encrusting Adeonella , 41.5 m. MTQ G26490, 16°31.653' S, 139°54.589' E, encrusting shell, 36.5 m. MTQ G26491, 16°26.574' S, 139°50.975' E, encrusting shell, 27.5 m. MTQ G26492, 16°31.064' S, 139°56.755' E, encrusting rock, 33 m.

Southeastern GoC: MTQ G26514, G26493, 16°40.914' S, 140°12.092' E, 33 m.

Etymology. Named for the Lardil people, the traditional owners of the land and surrounding seas of Mornington Island, Gulf of Carpentaria; noun in apposition.

Description. Colony encrusting. Autozooids relatively small (c. 0.3 × 0.25 mm; Table 7 ), rectangular to irregularly polygonal. Frontal shield convex, uneven, with relatively small, widely spaced pseudopores in pits (average 42 per zooid), separated by more than two pseudopore diameters, variable in shape, some kidney-shaped, extending to zooid borders. Interzooidal boundaries marked by thin raised rims and elongate areolar-septular pores. Lateral walls between zooids with 1–2 uniporous septula. Kenozooids occasionally replacing autozooids, lacking orifice and pseudopores, bearing avicularia of the same type and in the same position as those of autozooids.

Primary orifice pyriform, as wide as long (c. 0.8 mm), broadest distally, anter rounded, lunula restricted to distal half of orifice, poster with deep, semicircular sinus, condyles rounded, serrate. A low, thickened rim of calcification surrounding proximal side of orifice.

Each zooid with a single, small, subrounded suboral, medial avicularium on inflated cystid, with a tall protuberance of cystid proximal to avicularium occupying approximate centre of zooid; proximal edge of avicularium thus raised, directing avicularium proximofrontally; rostrum semicircular, crossbar complete, proximal and distal opesiae oval.

Ovicell recumbent upon frontal shield of distal zooid, as wide as zooid, not crossed by suture lines. Orifice dimorphism not distinctive but ovicellate orifices slightly wider than autozooid orifices (c. 0.09 vs 0.08 mm; Table 7 ).

Ancestrula with four spines, one pair midway, one pair distally.

Remarks. Calyptotheca lardil n. sp. is notable for having a smaller orifice and zooids than the other species described herein, with a tall protuberance of the avicularian cystid in the centre of the zooid, with frontally tilted avicularium. This taxon belongs to a group of species with a single, subrounded, suboral, medial avicularium on each zooid, which includes C. immersa ( Powell, 1967) , C. inclusa , C. kapaaensis Dick, Tilbrook & Mawatari, 2006, C. reniformis , C. subimmersa ( MacGillivray, 1879) , Schizomavella collina Cook, 1965 and S. incompta ( Hayward, 1988b) . Of these, only C. immersa , C. inclusa , C. reniformis and S. incompta share a pyriform orifice with C. lardil n. sp., and of these, only C. immersa shares the tall central protuberance. Both C. inclusa and C. reniformis have suboral avicularia with a trifoliate distal opesia and vicarious avicularia ( Harmer 1957; Tilbrook, unpubl. data), neither of which have been observed in C. lardil n. sp. Schizomavella incompta is known only from Mauritius and has additional proximal triangular adventitious avicularia on some zooids. Calyptotheca immersa from New Zealand has squared non-serrate condyles, immersed ovicells with Y-shaped suture lines and stronger orificial dimorphism than C. lardil (see Gordon 1989, p. 37, pl. 18).

Distribution. Known only from southeastern GoC, with most of the specimens found in the Bryomol Reef area encrusting small pebbles, shells and the habitat-providing bryozoan Adeonella sp., at depths of 27.5–41.5 m.

Figures

FIGURE 7. Calyptotheca lardil n. sp. A – C, holotype (MTQ G 26483). A, general view of autozooids, and ovicellate zooids, with a kenozooid at right centre; B, autozooid; C, primary orifice with suboral avicularium—note the oval distal opesia; D – E, paratype (MTQ G 26485). D, ancestrula; E, whole colony with ancestrula.

Tables

TABLE 7. Measurement (mm) and count data for Calyptotheca lardil n. sp. (holotype: MTQ G 26483)

Zooid length	Mean 0.309	Standard Deviation 0.019	Range N 0.275–0.332 10
Zooid width Autozooid orifice length Autozooid orifice width	0.250 0.080 0.079	0.036 0.003 0.003	0.210–0.316 10 0.075–0.085 8 0.076–0.085 8
Adventitious avicularium length Adventitious avicularium width Diameter of perforations in frontal shield	0.024 0.033 0.006	0.003 0.003 0.0006	0.020–0.029 10 0.027–0.036 10 0.005–0.007 10
Number of perforations in frontal shield Ovicell length Ovicell width	42.5 0.182 0.219	5.212 0.014 0.018	31–51 10 0.169–0.202 4 0.196–0.237 4
Ovicellate orifice length Ovicellate orifice width	0.079 0.090	0.001 0.001	0.078–0.080 3 0.089–0.091 3