Eucheilota paradoxica Mayer

Nagata, Renato Mitsuo, Júnior, Miodeli Nogueira & Haddad, Maria Angélica, 2014, Faunistic survey of Hydromedusae (Cnidaria, Medusozoa) from the coast of Paraná State, Southern Brazil, Zootaxa 3768 (3), pp. 291-326 : 306-307

Eucheilota paradoxica Mayer

( Fig. 19 )

References consulted. Kramp 1959b: 245. Kramp 1961: 172. Uchida & Sugiura 1975: 330–335, figs A– N. Carré & Carré 1990: 304–305, figs 1–3; Bouillon 1999: 425, fig. 3.93. Tronolone 2001: 111–114, fig. 27. Bouillon et al. 2004: 163, fig. 87. M. Tronolone 2007: 63–64, fig. 2.26.

Material. Municipality of Pontal do Paraná, Balneário de Praia de Leste (25º48’S – 48º04’W): 22/12/1997 — 5 specimens; (25º50’S – 47º55’W): 22/12/1997 — 2 specimens; (25º44’S – 48º21’W): 23/01/1998 — 2 specimens; (25º46’S – 48º12’W): 23/01/1998 — 18 specimens; (25º46’S – 48º12’W): 20/02/1998 — 8 specimens; (25º48’S – 48º04’W): 20/02/1998 — 5 specimens; (25º46’S – 48º12’W): 31/03/1998 — 20 specimens; (25º42’S – 48º27’W): 22/ 04/1998 — 6 specimens; (25º44’S – 48º21’W): 22/04/1998 — 8 specimens.

Reference specimens deposited. MZUSP 1486, 4 specimens. Dzoo-Cn 250, 2 specimens, Dzoo-Cn 251, 1 specimen.

World distribution. Western Atlantic Ocean; Florida ( USA), Bahamas, Belize ( Mayer 1910; Larson 1982), and Brazil (Migotto et al. 2002). Indian Ocean ( Santhakumari 1999). Pacific Ocean, in Japan ( Uchida & Sugiura 1975). Mediterranean Sea ( Carré & Carré 1990).

Distribution in Brazil. From the state of Rio de Janeiro to Santa Catarina, found in shallow waters and within bays (Navas-Pereira 1980; Vannucci 1963; Tronolone 2001, 2007; Nogueira 2011, 2012; this study).

Description. Umbrella higher than wide, mesoglea thick, 0.3–1.5 mm in diameter. Almost all specimens retained their typical umbrellar shape after collection and fixation. Manubrium flask-shaped, short, reaching less than half of the umbrella height. Four radial canals usually with medusa buds ( Fig. 19 ). Four marginal tentacles, with 1–3 pairs of lateral cirri, four rudimentary interradial bulbs with lateral cirri. 8 adradial large marginal statocysts. In a few specimens, some statocysts may be displaced to the interradial position. A single statolith per statocyst easily visualized by staining with methylene blue. Very small individuals (<0.5 mm in diameter) with only two marginal tentacles, alternated with two rudimentary bulbs, both with lateral cirri, and without medusa buds.

Systematic remarks. This species can be readily differentiated from others of the genus by the frequent presence of medusa buds on radial canals ( Kramp 1962), and four tentacular bulbs with lateral cirri alternating with rudimentary bulbs without tentacles, but with cirri ( Kramp 1959b, 1961, 1962 and Bouillon 1999).

Biological data. Most of our specimens of 0.3– 0.8 mm in diameter had medusa buds, beginning to develop near the manubrium. No adult medusae, with gonads, which develop after the budding stage, were found. Adults have never been collected in the Atlantic or Mediterranean ( Carré & Carré 1990); however Uchida & Sugiura (1975) reported both stages, successively in Japan. Bouillon et al. (2004) mentioned specimens with up to 5 mm in the Mediterranean, Uchida & Sugiura (1975) mentioned specimens measuring 2.9 mm that were highly developed, with the four interradial rudimentary bulbs developed into tentacular bulbs.

Figures

FIGURE 19 – 26. Eucheilota paradoxica Mayer: lateral view, radial canal with medusa bud (19); Clytia sp. Lamouroux: adult medusae with the base of the manubrium stretched, possible a sampling damage (20); adult medusae in oral view, linear gonads along radial canals (21), and a detail of the stretching of the base of manubrium (22); Obelia sp. Péron & Lesueur: oral view, specimen with 5 radial canals (23); Gossea brachymera Bigelow: adult medusae (24) detail of gonads (25), and marginal tentacles (26).