Hydromedusae observed during night dives in the Gulf Stream Author Schuchert, Peter Muséum d’histoire naturelle, C. P. 6434, CH- 1211 Genève 6, Switzerland peter.schuchert@ville-ge.ch Author Collins, Richard 880 NE 33 rd Street, Boca Raton, Florida, USA rc6684@icloud.com text Revue suisse de Zoologie 2021 2021-10-21 128 2 237 356 journal article 10.35929/RSZ.0049 172fa5c5-c0c4-4bd7-b710-d608237b8458 0035-418 5639938 Aequorea spec.2 Fig. 42 Material examined: BFLA4013 ; 1 specimen ; 17-DEC- 2018 ; preserved in alcohol for DNA extraction; 16S sequence MW528639 . Observations: Small, juvenile Aequorea medusa, 7 mm , no gonads. Stomach diameter 0.3 of bell diameter. About 30 broad radial canals. Tentacles not all visible, approximate range 18-30. Tentacle bulbs conical, not inflated, without keel or white abaxial line, without abaxial spurs. 16S data: The single sequence proved to be quite closely related to Gangliostoma guangdongensis Xu, 1983 ( Fig. 37 ). The base pair differences in the pairwise aligned sequences were 3.6%. Remarks: We found only one specimen of this lineage and it was too immature for being identified. Additionally, the animal was attempting to swallow a much lager ctenophore and was thus quite distorted. Its 16S sequence resembled the Chinese Gangliostoma guangdongensis . The genus Gangliostoma is distinguished from Aequorea by a papilla situated at the base of the stomach and between each pair of radial canals. This feature is not well documented and it is unclear what it is. No such papillae could be seen in the present specimen.