Solmaris corona ( Keferstein & Ehlers, 1861 )

Schuchert, Peter & Collins, Richard, 2021, Hydromedusae observed during night dives in the Gulf Stream, Revue suisse de Zoologie 128 (2), pp. 237-356 : 326-328

Solmaris corona ( Keferstein & Ehlers, 1861)

Fig. 55 A-C

Aegineta corona Keferstein & Ehlers, 1861: 94 , pl. 14, figs 7-9.

Solmaris (Solmarinus) coronantha Haeckel, 1879: 359 , pl. 20 figs 7-10, Canary Islands.

? Solmaris multilobata Maas, 1893: 45 , pl. 4 figs 1-5.

Solmaris corona . – Haeckel, 1879: 358. – Mayer, 1910: 437, figs 288-289. – Russell, 1953: 476, figs 313, pl. 28 fig. 2. – Kramp, 1961: 278. – Pages, Gili, Bouillon, 1992: 42, fig. 51. – Bouillon et al., 2004: 236, fig. 147. – Nagata et al., 2014: 313 , fig. 33.

Examined material: BFLA3837 ; 1 specimen; 19-NOV- 2018; size approximately 2-3 mm, 18 tentacles; preserved in alcohol for DNA extraction; 16S sequence MW528660 . – BFLA4123 ; 1 specimen; 06-JUN- 2019; size 9 mm, 25 tentacles; preserved in alcohol for DNA extraction; 16S sequence MW528679 . – BFLA4314 ; 1 specimen; 24-JAN-2020; size 2 mm, 15 tentacles; preserved in alcohol for DNA extraction; 16S sequence MW528706 . – 31-AUG-2018; 1 specimen photographed, 18 tentacles, not collected.

Observations: Umbrella diameter up to 9 mm, jelly lenticular ( Fig. 55A ), top with a broad, shallow apical projection; periphery with up to 25 lappets, distinctly rectangular ( Fig. 55 A-C), 1-3 statocysts per lappet ( Fig. 55A ). Stomach large, more than 2/3 of bell diameter, without gastric pockets, no peripheral canals. Presumable gonad tissue developing as slightly opaque ring on oral side of stomach ( Fig. 55A ). Up to 25 tentacles, issuing in about middle of bell height, curving upwards, rather stiff, but able to move and even to coil, evenly tapering to tip, length about 2-3 bell diameters, root short. Below tentacles no exumbrellar furrows, but thin peronia delimiting the lappets. Colour: stomach and tentacles a purple hue ( Fig. 55A ), some tentacle tips a very faint yellow ( Fig. 55B ).

16S Data: See Table 1 and Fig. 48 .

Distribution: In the eastern Atlantic, from Norway to South Africa, in the western Atlantic from Florida to Brazil, also Indian Ocean ( South Africa) ( Pagès et al., 1992; Nagata et al., 2014; this study). Type locality: Mediterranean, Bay of Naples.

Remarks: Our identification as S. corona was primarily based on the description given in Russell (1953) and Pages et al. (1992). It is somewhat tentative because our specimens were probably not fully grown as they did not attain the maximal tentacle number of 36 and size of 12-15 mm given in Kramp (1953). The observed maximal number of 25 tentacles compares more favourably with the numbers given in the original description for mature animals (27-30, 14 mm diameter; Keferstein & Ehlers, 1861). Russell (1953) provides a table with observed sizes and tentacle numbers for an Irish population and our specimens agree approximately. During the course of its development S. corona changes very little in general appearance. There is merely an increase in the number of marginal lappets, tentacles, and sense organs ( Russell, 1953).

It was not clear if the opaque ring in the stomach ( Fig. 55A ) is the developing gonad tissue or some residual, digested food. The slight purple colour let us favour it being the developing gonad tissue.

Figures

Fig. 55. Solmaris corona. (A) Specimen BFLA4123, diameter 9 mm. (B) BFLA4314, diameter 2 mm. (C) BFLA3837, diameter 2-3 mm.

Fig. 48. Maximum likelihood phylogenetic tree of Narcomedusae obtained with PhyML (GTR+G+I model) and based on 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. Some proveniences were obtained from Lindsay et al. (2017) or through personal communications. Red ODEHOV DUH QHZ VHTXHQFHV IURP WKLV VWXG\. &RORXUHG ER[HV LQGLFDWH IDPLO\ DI¿OLDWLRQV DFFRUGLQJ WR WKH FXUUHQWO\ XVHG V\VWHP. (") 'HQRWHV SRVVLEOH PLVLGHQWL¿FDWLRQV.