Geryonia proboscidalis ( Forsskål, 1775 )

Schuchert, Peter & Collins, Richard, 2021, Hydromedusae observed during night dives in the Gulf Stream, Revue suisse de Zoologie 128 (2), pp. 237-356 : 336-337

Geryonia proboscidalis ( Forsskål, 1775)

Fig. 61 A-B

Medusa proboscidalis Forsskål, 1775: 108 , pl. 36 fig. 1.

Geryonia hexaphylla Péron & Lesueur, 1810: 329 . – Haeckel, 1879: 295, synonym.

Dianaea endrachtensis Quoy & Gaimard, 1824: 566 , pl. 84 fig. 2. – Haeckel, 1879: 295, synonym.

Leuckartiara brevicirrata Haeckel, 1864b: 462 . – Haeckel, 1879: 295, synonym.

Leuckartiara longicirrata Haeckel, 1864b: 463 . – Haeckel, 1879: 295, synonym.

Geryonia umbella Haeckel, 1864b: 464 . – Mayer, 1910: 425, synonym.

Geryonia fungiformis Haeckel, 1864b: 465 , new name for Geryonia hexaphylla Péron & Lesueur, 1810 . – Mayer, 1910: 425, synonym.

Geryonia conoides Haeckel, 1864b: 466 .

Carmarina hastata Haeckel, 1864b: 467 , pl. 11 figs 1-10. – Mayer, 1910: 425, synonym.

Geryones elephas Haeckel, 1879: 294 , pl. 18 fig. 7, South Africa.

Geryonia dianaea Haeckel, 1879: 295 . – Mayer, 1910: 425, synonym.

Carmaris umbella Haeckel, 1879: 296 . – Mayer, 1910: 425, synonym.

Carmaris Giltschii Haeckel, 1879: 296 , pl. 18 fig. 8. – Mayer, 1910: 425, synonym.

Geryones mexicana Agassiz & Mayer, 1902: 149 , pl. 4 fig. 17. – Mayer, 1910: 425, synonym.

Carmaris rosea Agassiz & Mayer, 1902: 149 , pl. 4 fig. 18. – Mayer, 1910: 425, synonym.

Geryonia fungiformis . – Fol, 1873: 471, figs 1-3, pls 24-25, developement.

Geryonia proboscidalis . – Haeckel, 1879, 295. – Mayer, 1910: 425, fig. 282, pl. 53 figs 1-3, pl. 43 fig. 10, synonymy. – Berrill, 1950: 296, development. – Kramp, 1959a: 192, fig. 292. – Kramp, 1961: 237. – Kramp, 1968: 122, fig. 332. – Horridge, 1969: 348, figs 5-6, statocysts. – Goy et al., 1991: 119, fig. 47. – Bouillon et al., 2004: 237, fig. 150A-C. – Buecher et al., 2005: 35.

Examined material: BFLA4029 ; 1 specimen; 04-MAR-2019; diameter 10 mm; part preserved in formalin ( UF-013448 ) and part in alcohol for DNA extraction; 16S sequence MW528644 . – 26-MAR- 2019; 1 specimen photographed, diameter 20 mm, not collected.

Mediterranean, France, Bay of Villefranche-sur- Mer , 43.6963°N 7.3075°E; 25-APR-2016; diameter 70 mm, photos see DOI: 10.5281/zenodo.53890; whole specimen used for DNA extraction, 16S sequence KX355451 .

Description of Florida material: Bell almost hemispherical, 10 to 20 mm wide, jelly thick. Stomach small, on a long conical peduncle, peduncle reaching a length of about twice the bell height ( Fig. 61A ). Six radial canals, 3-7 centripetal canals betwen pairs of radial canals, ending blindly below apex of subumbrella. Gonads along the six primary radial canals, reaching from circular canal to apex of subumbrella, sheet-like, triangular, pointed end towards circular canal. Two types of tentacles. Six long, perradial tentacles with nematocyst rings, and six short interradial tentacles with adaxial nematocyst clusters, often held upwards adnate to subumbrella ( Fig. 61B ).

16S Data: The 16S sequence (GMW528644) shows few differences to other published sequences of G. proboscidalis ( Table 1 ). The p-distance to the Mediterranean specimen was 0.17%, and 0.33% to the one from Japan. More differences where found with sequence KT809331 (1.2%) originating from the Sea of Cortez (Bastian Bentlage, pers. com.).

Distribution: Occurs in tropical and subtropical parts of all three oceans, including also the Mediterranean, approximately between 35° and 35°S ( Kramp, 1957, 1965). Type locality: Mediterranean Sea ( Forsskål, 1775).

Remarks: With its six radial canals and the two types of tentacles, Geryonia proboscidalis is rather reliably identifiable. It is interesting to note the low 16S sequence divergences observed for the sample from Florida, the Mediterranean, and Japan. Geryonia proboscidalis could thus be a good example of a hydromedusan species with a truely circumglobal distribution.

Figures

Fig. 61. Geryonia proboscidalis. (A) Lateral view of whole, mature animal observed 26-MAR-2019. (B) Bell margin of immature specimen (BFLA4029), bell size approximately 10 mm. Note centripetal canals and the two types of tentacles.