Nausithoe sp.

Molinari, Clarissa Garbi, Maronna, Maximiliano Manuel & Morandini, Andre Carrara, 2020, New record of Nausithoe werneri (Scyphozoa, Coronatae, Nausithoidae) from the Brazilian coast and a new synonymy for Nausithoe maculata, ZooKeys 984, pp. 1-21 : 1

Nausithoe sp. Figs 1 , 3 , 4

Metagenetic species.

Solitary polyp with typical periderm tube, dark to light brown (Fig. 1C, D ), conical, with transverse rings on the surface with longitudinal striations (5 rings every 0.4 mm at 2 mm above base). Polyps 5.05-20.2 mm long; basal disk 0.63-0.66 mm in diameter; diameter just above the basal disk 0.14-0.4 mm; tube diameter at 2-mm height 0.09-0.45 mm, and at 5-mm height 0.35-0.45 mm; tube aperture diameter 1.28 mm. Tubes with 3-10 whorls of internal cusps (Fig. 1C ); closer to base, number of internal cusps per whorl is 16: 4 large (perradius) with additional cusps on the surface, 4 intermediate (interradius), and 8 small (adradius) (Fig. 3A ). Upper whorls with only 8 cusps: 4 large (perradius) with no additional cusps, and 4 intermediate (interradius) (Fig. 3B, C ). Polyps with 26-37 filiform tentacles (Fig. 1D ). Polydisc strobilation, with more than 100 ephyrae at a time. Medusa (Figs 2A, B , 4 ) entirely translucent, with slightly flattened smooth umbrella; 16 slightly elongated lappets with rounded margins; 8 rhopalia with statocyst and red ocelli. Live specimens measuring up to: 9.5 mm total diameter; 7.74 mm diameter between opposite rhopalia; 2.83 mm coronal groove diameter; gastric cirri approximately 0.9 mm in length; and tentacle length up to half the total diameter of the medusa. Stomach with 4 gastric septa, each with 2 gastric filaments (8 in total) (Figs 2A , 4D, E ). Gonads, 8, but not fully developed (Fig. 4A-C ); in fact, only a single individual had them and they were malformed (Fig. 4B, C ), so complete data about their morphology are lacking. Cnidome composed of only two nematocyst types: holotrichous isorhiza and heterotrichous microbasic eurytele (Fig. 5 ; Table 6 ).

Figures

Figure 1. Nausithoe sp. from Brazil. A tissue balls originated from polyp AC 02 ephyrae B emerged polyps from same tissue balls in A after 22 weeks, showing the polyp opening; note that the basal parts are fused C external view of part of polyp AC 18, showing by transparency the internal whorls of cusps (wc) D oral disc of polyp AC 01, showing the tentacle crown (tc) and the mouth opening (m) with the gastric longitudinal septa (gs) E polyp AC 02 releasing ephyrae.

Figure 2. Schematic view of a typical Nausithoe sp. adult medusa, illustrating the main characters. A aboral view B lateral view. dc diameter of coronal furrow dr diameter between rhopalia dt total diameter cg coronal grove gc gastric cirri m manubrium ml marginal lappets r rhopalium t tentacle e eyespot g gonad s statolith.

Figure 3. SEM of cross-sections of the tube of the polyp of Nausithoe sp. AC 02 at different heights. A more-basal series, with 16 cusps and additional cusps over 4 larger perradial cusps B and C two more-distal series (C being the highest along the tube), each with 8 cusps.

Figure 4. Adult medusae from polyps of Nausithoe sp. AC 10 (A-C) and AC 20 (D-H) A beginning of gonad (g) development B two gonads with gametic cells still differentiating C general view of a medusa that we managed to maintain until the gonads emerged (note degree of irregularities in this specimen, due to the long period in cultivation) D aboral view of 3 - month-old medusa, showing the radial muscle (rm), marginal lappets (ml), rhopalium (r), and tentacles (t) E detail of 6 - month-old medusa, showing gastric filaments (gf), rhopalium with ocelli (e), and statocyst (s), and coronal groove (cg); note, no trace of gonad development F, G and H Oral view of medusae, showing lips (l) and projection of the manubrium, from less projected (F) to more projected (H).

Figure 5. Photomicrographs of the two nematocyst types found in Nausithoe sp. A three heterotrichous microbasic euryteles discharged B holotrichous isorhiza capsules of two different sizes (large, grey arrow; small, black arrow) C a small discharged holotrichous isorhiza.