Clytia linearis ( Thornely, 1900 )

Schuchert, Peter & Collins, Richard, 2021, Hydromedusae observed during night dives in the Gulf Stream, Revue suisse de Zoologie 128 (2), pp. 237-356 : 312

Clytia linearis ( Thornely, 1900)

Fig. 46 A-B

Obelia linearis Thornely, 1900: 453 , pl. 44 fig. 6.

Clytia linearis . – Cornelius, 1982: 84, fig. 12. – Medel & Vervoort, 2000: 38, bibliography. – Peña Cantero & García Carrascosa, 2002: 149, fig. 28e-f, synonymy. – Lindner & Migotto, 2002: 541, figs 2-3, life cycle. – Schuchert, 2003: 160, fig. 20, synonymy. – Galea, 2007: 88 , figs 20G-I, pl. 2J-K. – Galea, 2008: 20 , fig. 4A-B. – Calder, 2013: 55 , fig. 15f, record Florida, taxonomy.

Examined material: BFLA4077 ; 1 specimen; 16-APR- 2019; size 3.5 mm; preserved in alcohol for DNA extraction; 16S sequence MW528668 .

Observations: Medusa 3.5 mm, bell when relaxed rather flat ( Fig. 46A ), height about 1/3 of diameter, jelly moderately thick. Manubrium small, four very short, simple perradial lips. Four radial canals, two of them (accidentally?) approximated and therefore not giving a perfectly tetraradial symmetry. Gonads male, very thick and long, sausage shaped, arising at short distance from manubrium and stretching to almost circular canal. 39 tentacles, each arising from a spherical basal bulb, thin and long. 1 to 2 atentaculate, smaller bulbs. At least as many or more statocysts as tentacles. Colour: all tissues with a green hue, transparent.

16S Data: The 16S sequence of our single sample was compared to the 16S dataset of Cunha et al. (2017). It was nested within the well supported Clytia linearis clade (tree not shown). Its sister clade is made up of the sequences AY789810 and AY346362 from Beaufort NC and the Mediterranean respectively (provenence acc. Govindarajan et al., 2006). The sequence divergence from AY789810 is 2.5%.

Distribution: Circumglobal in shallow warm waters ( Lindner & Migotto, 2002). Type locality: Papua New Guinea, New Britain, Blanche Bay ( Thornely, 1900; hydroid).

Remarks: The identification of this medusa was based solely on its 16S sequence which was nested within a well supported Clytia linearis clade. The morphology matched rather well the description of Clytia linearis in Lindner & Migotto (2002) which was based on cultivated medusae. It only had slightly more tentacles and much larger gonads, both easily attributable to more optimal growth conditions. Notable were the rather flat umbrella and the small size.

Figures

Fig. 46. Clytia ssp. (A-B) Clytia linearis, BFLA4077, bell dimeter 3.5 mm. (C) Clytia spec. 1, BFLA4283, bell diameter 10 mm. (D)? Clytia spec. 2, BFLA4274, 3 mm; arrow points to incomplete centripetal canal. (E)? Clytia spec. 2, BFLA4269, 4 mm. (F)? Clytia spec. 2, BFLA4253, 3 mm, has 5 complete radial canals. (G)? Clytia spec. 2, doubled manubrium of animal photographed 06-DEC-2019, 6 mm bell, not collected.