Trochocyathus sp.

Cairns, S. D., 2004, The Azooxanthellate Scleractinia (Coelenterata: Anthozoa) of Australia, Records of the Australian Museum 56, pp. 259-329 : 286-287

Trochocyathus sp. cf. T. (Trochocyathus) aithoseptatus Cairns, 1984

Figs. 4G,H

Not Paracyathus conceptus Gardiner & Waugh, 1938: 184 .

Paracyathus conceptus .– Wells, 1964: 113, pl. 1, figs. 11–12 (Qld).– Veron, 1986: 608 (listed).

Material examined. 14 miles (= 22.4 km) east of Jumpin Pin , Queensland, 86 m, 1, USNM 68373 .

Description of specimen reported by Wells, 1964 (USNM 68373). Corallum ceratoid: 13.8× 10.2 mm in calicular diameter and 21.7 mm in height, firmly attached through a pedicel 7.3 mm in diameter. Costae well defined and granular, separated by intercostal grooves of equal width. Costae near calice and upper, outer edges of all septa chocolate brown, the remaining corallum white. Septa hexamerally arranged in 5 incomplete cycles (58 septa) according to the formula: S1>S2>S3>S4>S5, there being little difference in the width of the S1–4. P1 small (0.6 mm wide) and sit very low in fossa. S2 slightly broader (0.8 mm) but also sit low in fossa, along with the P1 forming the lower palar crown. P3 much broader (1.25 mm) and project much higher in fossa, forming the upper crown of 12 elements. S4 flanked by a pair of S5 also bear a large prominent palus (P4), contributing to the upper crown. Fossa deep; columella consists of about 35 slender elements.

Remarks. The single specimen reported by Wells (1964: 113) from “ 14 miles due east of Jumpin Pin (27°45'S), 47 fms.”, Queensland as Paracyathus conceptus differs from that species (syntypes of which are deposited at the BM 1950.1.9.839–850, 859–867) in having a thinner, nonepithecate wall; a pigmented corallum; and thinner septa. Indeed, Wells’ specimen belongs in a different genus, Trochocyathus , as it has two discrete crowns of paliform lobes. Among the 25 species of Trochocyathus known from the Indo-West Pacific region (Cairns et al., 1999), it is most similar to T. aithoseptatus Cairns, 1984 (known only from the Hawaiian Islands, 371–454 m), both species having the same number of septa, pigmentation pattern, and general shape. Trochocyathus aithoseptatus differs in having a thinner pedicel and more flared calice, a shallower fossa, pigmentation that extends to the pali, and pali of uniform size, often with poorly developed P4. Although the Queensland specimen probably represents an undescribed species, one specimen is not considered to be enough to properly distinguish or describe it.

Distribution. Known only from east of Jumpin Pin, Queensland, 86 m.