Carcharodorhynchus flavidus Brunet, 1967

(Fig. 7)

Known distribution. Several localities in the Mediterranean: France (Brunet 1967); several localities in Sardinia (Italy) (Gobert et al. 2017). Lanzarote (Canary Islands) (Gobert et al. 2017). Possibly North Carolina, United States (Whitson et al. 2011).

Material and distribution in Cuba. Three specimens studied alive and whole mounted (HU X.1.08– X.1.10), collected in Siboney (September 4, 2016; December 14, 2017), sublittoral, fine-grained sand with organic matter, 0.7–2 m depth, salinity 32–35 ‰.

Remarks. The live animals from Cuba are about 1.5–2 mm long, yellowish, without eyes. There is a pale belt near the posterior body end, corresponding to the single adhesive girdle. Proboscis (Fig. 7A: pr, 7B–C) symmetric to lightly asymmetric; largest lip 126–130 µm long (n = 2) and the smallest one 118–119 µm long (n = 2). Proboscis with paired fields of shark-tooth-shaped denticles situated along each proboscis lip, separated by a characteristic ‘basal gap’ (see Brunet, 1967; Schilke 1970a; Whitson et al. 2011; Gobert et al. 2017). In the basal half of the toothed belts, the denticles are 1–2 µm long (x = 1 µm; n = 23) and are more or less ordered in three or four rows; in the distal half the denticles appear a bit larger 1–2 µm long (x = 2 µm; n = 12) and are ordered in two rows. In live animals, polygonal glands were observed in the internal surface of the lips (Fig. 7B: prg); the largest ones arranged in two rows on the central longitudinal axis of each lip. These larger glands are accompanied by smaller glands. None of these glands are observable on the whole mounts. Pharynx (Fig. 7A: ph) located at 50%, being about 7% of the body length in live animals.

Three pairs of testes (Fig. 7A: t) are arranged in two rows in front of the pharynx. Copulatory bulb (Fig. 7D) 63–119 µm long (x = 92 µm; n = 3); it comprises the prostate vesicle and the spiny cirrus. Prostate vesicle (Fig. 7D: pv) 67–87 µm long (x = 77 µm; n = 2). Spiny cirrus (Fig. 7D: ci) 26–35 µm long (x = 32 µm; n = 3), proximally 7–12 µm wide (x = 9 µm; n = 3) and distally 17–19 µm wide (x = 18 µm; n = 3).