Aequorea spec.2

Schuchert, Peter & Collins, Richard, 2021, Hydromedusae observed during night dives in the Gulf Stream, Revue suisse de Zoologie 128 (2), pp. 237-356 : 305

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.

Figures

Fig. 42. Aequorea spec. 2. (A-B) BFLA4313, size 7 mm, oral view.

Fig. 37. 16S maximum likelihood phylogenetic tree of the genus Aequorea and related genera obtained with PhyML (GTR+G+I model) using about 600 bp positions of the mitochondrial 16S gene. Node-support values are bootstrap values of 100 pseudoreplicates (shown only if> 70%). Sequence labels start with the GenBank numbers (except for identical haplotypes) permitting the retrieval of more information. Red labels are new sequences from this study, for the taxa in bold either a voucher specimen or photos of it have been examined. Notes: *1) Unpublished, L. Leclère, pers. comm. *2) See Material & Methods. *3) Could be a misidentification. *4) Unpublished, A. Hosia & L. Martell, pers. comm., see Fig. 39A.