Solmaris flavofinis, Peter, 2021

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

Solmaris flavofinis n. spec.

Fig. 56 A-H

Holotype: BFLA4068 , 10-APR-2019; size 9 mm, mature female, 9 tentacles; part preserved in formalin and deposited as UF-013779 (damaged), small part preserved in alcohol for DNA extraction (MHNG- INVE-0137376); 16S sequence MW528665 .

Paratype: BFLA4273 ; 04-DEC-2019; size 9 mm, 8 tentacles; preserved in formalin and deposited as UF-013841 .

Other material: BFLA4243 ; 1 specimen; 11-NOV- 2019; size 9 mm, 11 tentacles; preserved in alcohol for DNA extraction; 16S sequence identical to MW528665 . – BFLA4250 ; 1 specimen; 23-NOV-2019; size 8 mm, 10 tentacles, mature female; preserved in alcohol for DNA extraction; 16S sequence MW528693 .

Etymology: The specific epithet is derived from the Latin words flavus (yellow) and finis (end), an allusion to the yellow tentacle tips.

Description: Bell diameter 8-9 mm, height ~ 4-5 mm, lower part shaped somewhat conical, upper part less steep, with small, rounded apical projection ( Fig. 56C ); lower third of bell composed of 8 to 11 rectangular lappets ( Fig. 56 A-F), 1-2 statocysts per lappet ( Fig. 56E ). Stomach large, 2/3 of bell diameter, flat, without gastric pockets, no peripheral canals. Gonad tissue developing on periphery of oral side of stomach ( Fig. 56A, B, F ), only females unambiguously identified, forming up to 8 very large oocytes ( Fig. 56B ), often but not always in perradial position, size estimate ~0.7 mm, flattened lentil-shaped, well visible germinal vesicle (nucleus). 8 to 11 thin tentacles, issuing in about 1/3 of bell height, held upward ( Fig. 56C ) or downward ( Fig. 56A ), rather stiff, but able to move and even to coil ( Fig. 56F ), evenly tapering to tip, length about two bell diameters, root short ( Fig. 56G ). Below tentacles no exumbrellar furrows, but thin peronia delimiting the lappets. Statocysts bipartite, with inverted cone as base and spherical end with statocysts ( Fig. 56H ). Colour: colourless except for yellow tentacle tips ( Fig. 56A, D ).

16S Data: See Table 1 and Fig. 48 . The p-distance to S. corona was very high (32%).

Remarks: The combination of the traits tentacle number (9-11), size (8-9 mm), and shape of the marginal lobes did not fit any of the known and accepted Solmaris species listed in Bouillon et al. (1991). Both the 16S and the morphological traits varied only in a relatively narrow range and we are convinced that these medusae represent a distinct species. The species resembling S. flavifinis most closely is the Mediterranean Solmaris flavescens ( Kölliker, 1853) (for a good description see Mayer, 1910: 434, figs 284-286). Solmaris flavescens differs in being considerably larger (diameter 15-23 mm) and has more tentacles (usually 13-15, exceptionally 12 or 17). While the yellow tentacle tips of S. flavifinis permitted distinguishing it immediately from the co-occurring S. corona (see above), this is not a diagnostic trait because it is shared with S. flavescens ( Kölliker, 1853: 322; Gegenbaur, 1857: 264; Metchnikoff, 1886: 19[257]). Another trait shared with S. flavescens is the large size of the oocytes, but several other Narcomedusae also have such large eggs (see table 4 in Bouillon, 1987).

Figures

Fig. 56. Solmaris flavofinis n. spec. (A-C) Holotype (BFLA4068), diameter 9 mm. (A) Oblique view from aboral side. (B) View from aboral side, note large oocytes with germinal vesicles. (C) Lateral view. (D-F) BFLA4250, diameter 8 mm. (D) Lateral view. (E) Close up of three lappets with statocysts (arrow). (G) BFLA4243, 9 mm. (H) BFLA4273, preserved sample, statocyst enlarged.

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.