Calyptotheca tenuata Harmer, 1957

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 : 160-163

Calyptotheca tenuata Harmer, 1957

( Figure 5 , Table 5 )

Calyptotheca tenuata Harmer, 1957: 1016 (part), pl. 68, figs 16, 17 (Badjo Bay and Muaras Reef material); Liu et al. 2001: 650, pl. 63, figs 1–3.

? Calyptotheca tenuata: Ristedt & Hillmer 1985 , 142, pl. 4, fig. 1; Scholz 1991: 311, pl. 15, figs 4, 6, pl. 16, fig. 1. Not Calyptotheca tenuata: Harmer 1957: 1016 , pl. 68, figs 16, 17 (Amboyna material); Ryland & Hayward 1992: 259, fig. 18b, c ( C. perpendiculata ); Tilbrook 2006: 220, pl. 48A, B ( C. rupicola ).

Material examined. Holotype: NHMUK 1980.2.1.19 (325.F3/Harmer no.1077), dry, Siboga Station 50, Badjo Bay, West Flores, 0– 40 m. Paratypes: NHMUK 1980.2.1.19 (325.F4/Harmer no.1077), Canada Balsam prep., same data as holotype; NHMUK 1980.2.1.20 (465.D/Harmer no. 1079), Siboga Station 91, Muaras Reef, East Borneo, 0–54 m; NHMUK 2002.1.23.14 (672.C/Harmer no. 1080), Siboga Station 181, Amboyna, 0– 54 m.

Bryomol Reef: MTQ G26474, G26475, 16°27.343' S, 140°52.712' E, encrusting Steginoporella , 41 m. MTQ G26476, 16°29.31' S, 140°56.513' E, 39 m. MTQ G26477, 16°27.627' S, 140°51.171' S, encrusting Adeonella , 26.5 m. MTQ G26478, 16°31.653' S, 140°54.589' E, encrusting Petraliella , 36.5 m.

Southeastern GoC: MTQ G26479, G26480, 16°50.029' S, 140°11.999' E, encrusting Steginoporella , 23 m. MTQ G26481, G26482, 16°51.189' S, 140°19.387' E, encrusting Steginoporella , 23 m. MTQ G26426, G26502, 15.92213° S, 139.89779° E, encrusting Cigclisula , 39.4 m.

Eastern GoC: MTQ G26500, 14°49.702' S, 140°11.994' E, encrusting Cigclisula , 59 m.

Description. Colony encrusting. Autozooids rectangular to irregularly pentagonal (c. 0.5 × 0.4 mm; Table 5 ). Frontal shield flattened to slightly convex with large, round, regularly spaced pseudopores (average 89 per zooid), separated by approximately the width of a pseudopore, extending to zooid borders; interzooidal boundaries marked by slightly elevated rims, marginal areolar pores large to very large, some triangular.

Primary orifice large, oval, wider than long (c. 0.11 × 0.15 mm), anter rounded, slightly sunken, lunula restricted to distal third of orifice, sinus a shallow rounded arc, condyles large, rectangular, not serrate. A low, thickened rim of calcification surrounding proximal side of orifice.

Adventitious avicularia infrequent, sometimes one, rarely two per zooid, normally occupying a distolateral angle of the zooid proximolateral to orifice, occasionally occurring laterally, at a proximal angle or on ovicells, directed medially or to centre of frontal shield, semi-elliptical proximally, acuminate distally, curved over inflated cystid, proximal opesia very small, often slit-like, distal opesia a rounded V-shape; mandible widely triangular proximally, distal portion acicular and basally curved. Vicarious avicularia absent.

Ovicell recumbent upon frontal shield of distal zooid, not crossed by suture lines, approximately circular (c. 0.3 × 0.3 mm). Orifice dimorphism not distinctive but ovicellate orifices slightly wider than autozooidal orifices (c. 0.16 mm vs 0.15 mm; Table 5 ).

Remarks. Calyptotheca tenuata is distinguished by its relatively large dimensions, with larger zooids, orifices and pseudopores, the latter more closely spaced compared to the other species described herein, and the strongly oval orifice, wide shallow sinus, and wide, acuminate, basally curved avicularia. Calyptotheca incusa Tilbrook, 2006 has similar avicularia, but they are distolateral to the orifice; C. triquetra ( Harmer, 1957) has triangular, basally curved avicularia, but they are suboral and medial. Orificial shape and condyles in these two species also differ from those of C. tenuata .

Two other Calyptotheca species have narrowly triangular, medially or proximomedially directed avicularia and a large oval orifice with smooth condyles: C. perpendiculata Tilbrook, 2006 and C. rupicola Hayward & Ryland, 1995 . Calyptotheca tenuata is distinguished from both by the shorter, wider (width approximately half the length; Table 5 ), acuminate, basally curved avicularia and smaller orificial dimensions. The avicularia of C. rupicola are rare, not occurring in pairs, bluntly triangular and long, reaching almost to the zooid centre, and the orifice is larger and more oval than that of C. tenuata (c. 0.13 × 0.19 mm [ Hayward & Ryland 1995] vs 0.11 × 0.15 mm). The orifice is surrounded by well-developed nodular thickening, often more developed proximally, which forms a distinct peristomial rim ( Hayward & Ryland 1995, p. 555, figs 9F, 10A, B). Tilbrook’s (2006) C. tenuata matches this description and C. tenuata of Ristedt & Hillmer (1985) and Scholz (1991) could also be C. rupicola . The avicularia of C. perpendiculata are also long, reaching the zooid centre but occurring at the widest part of the zooid, and perpendicular to the longitudinal axis; the orifice is very large (c. 0.17 × 0.22 mm; Tilbrook 2006, p. 222, pl. 48C, D).

Harmer’s (1957) synonymy includes specimens from Sri Lanka, the Philippines and New Caledonia but his material in NHMUK includes at least three species and the specimens of C. tenuata sensu stricto are only from Indonesia. The Amboyna material differs in having the avicularian cystid flush with the frontal shield, the rostrum flat and the mandible evenly tapered to the tip.

Distribution. Calyptotheca tenuata was originally described from West Flores, Indonesia, and it is known from Indonesia, China ( Liu et al. 2001) and the GoC, where it was found encrusting the habitat-providing bryozoans Steginoporella , Adeonella , Petraliella and Cigclisula at 21– 59 m. C. tenuata was the second commonest Calyptotheca species in the Gulf of Carpentaria Collection and this is the first record of C. tenuata in Australian waters.

Figures

FIGURE 5. Calyptotheca tenuata Harmer, 1957. A, MTQ G 26474, ovicellate zooids. B, MTQ 26475, avicularium with mandible. C – E, MTQ G 26474. C, autozooid and ovicellate zooids; D, primary orifice; E, autozooid and ovicellate zooids.

Tables

TABLE 5. Measurement (mm) and count data for Calyptotheca tenuata (MTQ G 26474).

	Mean	Standard Deviation	Range N
Zooid length	0.528	0.085	0.402–0.645 10
Zooid width	0.433	0.056	0.371–0.519 10
Autozooid orifice length	0.111	0.009	0.097–0.124 10
Autozooid orifice width	0.146	0.006	0.134–0.156 10
Adventitious avicularium length	0.165	0.009	0.153–0.181 10
Adventitious avicularium width	0.087	0.009	0.072–0.099 10
Diameter of perforations in frontal shield	0.020	0.001	0.018–0.022 10
Number of perforations in frontal shield	88.7	17.26	61–113 10
Ovicell length	0.279	0.018	0.255–0.312 10
Ovicell width	0.337	0.039	0.294–0.404 10
Ovicellate orifice length	0.106	0.004	0.098–0.112 10
Ovicellate orifice width	0.156	0.006	0.146–0.165 10