Eutima, McCrady, 1859

Buecher, Emmanuelle, Goy, Jacqueline, J, Mark & Gibbons, 2005, Hydromedusae of the Agulhas Current, African Invertebrates 46, pp. 27-69 : 56

Eutima ? commensalis Santhakumari, 1970

Eutima ? commensalis: Santhakumari 1970: 114–118 , figs 2–6.

Description: Two specimens from two stations. Umbrella hemispherical, dome-shaped, as broad as tall; without apical projection; up to 5.3 mm in diameter. Exumbrella surface smooth. Mesoglea thick. Peripheral canal and four radial canals present; radial canals narrow, with smooth margin, unbranched, extending from umbrella margin across underside of bell and along gastric peduncle to manubrium; without centripetal canals. With eight tentacles (four perradial, four interradial) connected to peripheral canal, arising from slightly swollen, linear bulbs on umbrella margin. Tentacles long (perradial longer than interadial), hollow, unbranched, filiform.With approx. 30 small, atentaculate marginal swellings or warts (appear to be four per octant, which may be lost on preservation). All marginal bulbs and warts without keel, and with neither excretory papillae nor excretory pores; lateral cirri present. Manubrium short, not connected to radial canals by mesenteries. Mouth simple, quadrate, with four lips. Gastric peduncle short, slender, tapering, reaching to level of velum. Statocysts closed, eight in number (two per quadrant). Without ocelli. With four gonads; thick, linear, may be sinuous, extending from bell margin, along length of subumbrella surface of radial canals and onto gastric peduncle.

Material examined: H5056.

Comments: Nineteen medusae are considered valid by Bouillon and Boero (2000 b), nine of which have previously been recovered from the Indian Ocean (Kramp 1961, 1965): E. japonica Uchida, 1925 , E. curva Browne, 1905 , E. gegenbauri ( Haeckel, 1864) , E. hartlaubi Kramp, 1958 , E. levuka ( Agassiz & Mayer, 1899) , E. mira McGrady, 1857 , E. modesta (Hartlaub, 1909) , E. mucosa Bouillon, 1984 , and E. orientalis (Browne, 1905) . Although most species can generally be distinguished by the number of marginal tentacles and bulbs, and the number, and distribution, of the gonads and the relative length of the gastric peduncle—and both Santhakumari (1970) and Bouillon (1984) usefully tabulate the morphological characteristics of each species—the medusa of E. commensalis is very similar to that of E. japonica . Indeed, mature specimens can only really be separated if they are in excellent condition and have undamaged umbrella margins; E. japonica has up to 32 marginal warts and E. commensalis has up to 48 warts. In tentatively assigning these specimens to E. commensalis we take cogniscence of the fragility of the marginal warts and hence the possibility of their loss during collection and preservation, and are guided by the conclusions of Kubota (2000). We also recognise that E. japonica is restricted to the North Pacific Ocean.

Distribution: North Indian Ocean, Arabian Sea. Epipelagic. Neritic. This is the first record from the south-west Indian Ocean.