Geryonia proboscidalis

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. 61 A). 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. 61 B). 16 S Data: The 16 S sequence (GMW 528644) 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 KT 809331 (1.2 %) originating from the Sea of Cortez (Bastian Bentlage, pers. com.).

Fig. 61 A-B

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 16 S 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.

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).

Examined material: BFLA 4029; 1 specimen; 04 - MAR- 2019; diameter 10 mm; part preserved in formalin (UF- 013448) and part in alcohol for DNA extraction; 16 S sequence MW 528644. – 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, 16 S sequence KX 355451.