Hydroids (Cnidaria, Hydrozoa) of the Danish expedition to

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142 Fig. 3. Conopora major Hickson & England, 1905. A. Colony, height 2.5 cm. B. Schematic organization of the cyclosystem, split longitudinally, with ampulla on its side. Note that lower dactylopores are not always as distinct as shown here. – Scale: B = 0.2 mm. by polychaete irregularly arranged, in distal branches sympodial in arrangements, shifted only slightly to one side of branch, distal ones slightly standing out, proximal ones flush to slightly recessed into branch coenosteum. Cyclosystems circular to slightly irregular in shape, 1 mm in diameter, 9–16 dactylopores per nondiastemate cyclosystem (mean 12.2, S.D. 1.6, n = P. SCHUCHERT 47, 10 colonies, most frequent value (mode) 12), one pseudoseptum occasionally thicker than others, adaxial dactylopores of older cyclosystems often filled by coenosteum (diastema). Gastropores, about 0.4 mm in diameter. Gastropore tubes up to 1.2 mm deep, divided into three sections of approximately same height. Upper section cylindrical, bordered by pseudoseptae; below this part a middle section delimited below by the ring of the lower dactylopores; lowest part hemispherical, not delimited by constriction from middle part or constriction very shallow and indistinct. Ring of lower dactylopores can be absent. Ampullae internal, ellipsoidal cavities, only present around cyclosystems; efferent pores on the pseudoseptae or in the gaps between them. Remarks The present samples came from a site near the Kei Islands that is only about 40 km away from one of the type localities of Conopora major. All colonies showed little variation and matched perfectly the description of Conopora major given in Hickson & England (1905), notably also the colony form (Fig. 2A). Broch (1936) assigned material from Mauritius to C. major. His colonies were more or less regularly pinnate and had their cyclosystems on the anterior side only. Furthermore, the diameter of the cyclosystems in Broch’s samples measured 1.5–1.8 mm in diameter, which is considerably more than the 1 mm observed here, or the 1.2 mm observed by Hickson & England (1905). Thus, the population studied by Broch perhaps belongs to another species, but due to the lack of information on the geographic variability of this species it seems impossible to draw reliable conclusions. Cairns (1991) re-described the closely similar Conopora verrucosa (Studer, 1878) and regarded Conopora major as a potential junior synonym. Cairns’ (1991) material from New Zealand differs from the present one by having a uniplanar growth versus a bushy and irregular growth; by the abundant nematopores that make the surface warty while in the present material these nematopores are quite rare; by the longer branches with more than 3 cyclosystems; by gastropores that are twice as deep, and by the regular presence of a constriction in the gas-
HYDROIDS OF THE DANISH EXPEDITION TO THE KEI ISLANDS tropore. These differences, and in particular the difference in colony form, made me hesitate to synonymize C. verrucosa and C. major. Distribution Indonesia, ?Mauritius. Type localities: Kei Islands (5°28.4’S, 132°00.2’E, 204 m) and Sulawesi (1°33.5’N, 124°41’E, 1901 m). Family Cordylophoridae Turritopsis cf. nutricula McCrady, 1859 Fig. 4. Turritopsis nutricula McCrady, 1959: 55, pls 4–5. – Russell 1953: 115, figs 54A–C, 55, 56, pl. 5: figs 1–5, pl. 29. – Kramp 1968: 27, fig. 66. – Millard 1975: 76, figs 24F–G. – Calder 1988: 8, figs 5–6, synonymy. – Schuchert 1996: 16, fig. 5a–e, synonymy. – Migotto 1996: 11, fig. 3a–c. Fig. 4. Turritopsis nutricula McCrady, 1859; material from Ambon. A. Shoot with medusae buds. B. Advanced medusa bud, note the coloured interradial patches (stippled). – Scales: A = 0.5 mm; B = 0.1 mm. 143 ?Dendroclava Dohrnii Weismann, 1883: 26. – Pictet 1893: 6, pl. 1: figs 1–2. ?Corydendrium chevalense Thorneley, 1904: 109, pl. 1: fig. 4. Material examined: Kei Islands Expedition, 28.02.1922, Ambon, harbour pier, 1 m, on Pennaria disticha and sponges, with medusae buds. – Kei Islands Expedition station 37, on hydroids and other material, with medusae buds. – MHNG INVE 31269, Bay of Ambon, material of Pictet (1893), labelled Dendroclava Dohrni, collected 15.7–12.8.1890, on Pennaria disticha, with medusae buds, preserved with HgCl 2 . – MHNG INVE 32617, Thailand, Andaman Sea, Koh Bi Da Nok, coll. A, Faucci, 6 Apr 2000, 12–18 m, with medusae buds. – MHNG INVE 29753, Mediterranean, Mallorca, Cala Murada, 16.8.2000, 2 m, examined alive, newly released medusae observed. – New Zealand material: see Schuchert (1996). Description Hydroid branched, monosiphonic or polysiphonic, 0.5–2 cm in height, arising from creeping, reticulate stolons. Branches and pedicels of hydranths adnate for some distance then curving outwards, diameter of branches 0.1–0.15 mm. Perisarc double layered, outer layer straight, inner layer undulated. Hydranths 0.5–1.0 mm, spindle-shaped, with up to 20 filiform tentacles scattered in distal ¾ of hydranth. Gonophores medusae developing on hydranth pedicels (in perisarc-covered region). Medusa buds spherical. Oldest buds observed with 4 radial canals, several tentacles, 8 eye-spots, manubrium with four interradial pads consisting of large, darkly coloured cells. Nematocysts: desmonemes 3.5 x 2 µm, microbasic euryteles (5.5–6) x (2.5–3) µm. Remarks Turritopsis hydroids and young medusae possess some characteristic traits that facilitate their identification: the double-layered perisarc and the interradial patches of coloured cells on the manubrium of the medusa. The first Indonesian record of a hydroid referable to Turritopsis was made by Pictet (1893, as Dendroclava dohrni). Reexamination of Pictet’s original material clearly showed that it belongs to Turritopsis. The medusa phase of Turritopsis is also known to occur in the region (Kramp 1968, as T. nutricula). Although the hydroid phase and young medusa of the specimens from Indonesia, the Andaman Sea, New Zealand, and the Mediterranean appear
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