Rhopalonema velatum Gegenbaur, 1857

Mendoza-Becerril, María A., Estrada-González, Mariae C., Mazariegos-Villarreal, Alejandra, Restrepo-Avendaño, Luisa, Villar-Beltrán, Rogelio D., Agüero, José & Cunha, Amanda F., 2020, Taxonomy and diversity of Hydrozoa (Cnidaria, Medusozoa) of La Paz Bay, Gulf of California, Zootaxa 4808 (1), pp. 1-37 : 5-7

Rhopalonema velatum Gegenbaur, 1857

Figs. 2 K–L, 3A–B

Rhopalonema velatum Gegenbaur 1857: 251 , pl. 9, figs. 1–5. — Bigelow 1909: 129, pl. 2, fig. 8, pl. 45, fig. 11. — Alvariño 1969: 46. — Segura-Puertas 1984: 42, pl. 10, fig. 4. — Alvariño 1999: 7, 22, 33, figs. 27a, 27b. — Segura-Puertas et al. 2010: 107. — Jáquez-Bermudez et al. 2013: 39. — Guerrero-Ruíz et al. 2014: 394, fig. 1. — Gamero-Mora et al. 2015: 115.

Rhopalonema velatim . — Foerster 1923: 47 (incorrect spelling).

Type locality. Mediterranean Sea ( Gegenbaur, 1857).

Material examined. Medusa—PB7_13, sampling site 2 (1), immature, 27ºC; PB7_1, sampling site 3 (1), immature, 26.5ºC.

Description. Umbrella broader (1.0– 1.3 mm wide) than high (0.7–0.8 mm long), with a conical apical thickening, and a well-developed velum (0.4 mm wide). Manubrium small (0.1–0.2 mm long), with an octagonal base (0.3–0.4 mm wide), without peduncle, and mouth with four simple lips. Eight straight radial canals; narrow ring canal. Sixteen solid marginal tentacles, eight perradial and eight interradial. Four to eight free ecto-endodermal statocysts along each marginal tentacle.

Nematocysts (length x diam.). Perradial and inter-radial marginal tentacle, stenotele (13.6–15.1 x 13.3–15.0 µm), desmoneme (6.2–6.9 x 3.6–4.6 µm).

More detailed description in Mayer (1910) and Russell (1953).

Taxonomic status. Accepted. AphiaID 117865.

Distribution. In warm waters of all oceans, occasionally occurring in temperate and cold waters ( Russell 1953; Kramp 1961; Ramírez & Zamponi 1980; Segura-Puertas et al. 2010). In Mexican Pacific it has been registered in Baja California ( Alvariño 1969), Baja California Sur (Punta Eugenia and locality not specified) ( Bigelow 1909; Alvariño 1969; Alvariño 1999), Sonora, Sinaloa ( Alvariño 1969), Nayarit ( Bigelow 1909), Jalisco to Michoacán ( Segura-Puertas 1984; Segura-Puertas et al. 2010; Jáquez-Bermudez et al. 2013; Gamero-Mora et al. 2015), Guerrero (Acapulco and locality not specified) ( Segura-Puertas 1984; Guerrero-Ruíz et al. 2014; Gamero-Mora et al. 2015) and Oaxaca ( Bigelow 1909; Segura-Puertas 1984).

Figures

FIGURE 2. A–D Solmundella bitentaculata (Quoy & Gaimard, 1833): A, lobed umbrela margin; B, peronia; C, ectodermal statocyst; D, nematocyst of medusa; a, macroisorhizas; b, microisorhizas. E–J Liriope tetraphylla (Chamisso & Eysenhardt, 1821): E, medusa; F, gonad; G, centripetal canal; H, marginal tentacles; I, ecto-endodermal statocyst; J, nematocyst of medusa; a, macrobasic eurytele; b, microbasic eurytele. K–L Rhopalonema velatum Gegenbaur, 1857: K, umbrela medusa; L, velum and tentacles. Scale equals A, B, F–I, K, L—200 µm; C—50 µm; D—12 µm; E—500 µm; J—20 µm.