Cheliplana hypergyna Boaden, 1965

Gobert, Stefan, Diez, Yander L., Monnens, Marlies, Reygel, Patrick, Van Steenkiste, Niels W. L., Leander, Brian S. & Artois, Tom, 2021, A revision of the genus Cheliplana de Beauchamp, 1927 (Rhabdocoela: Schizorhynchia), with the description of six new species, Zootaxa 4970 (3), pp. 453-494 : 473-474

Cheliplana hypergyna Boaden, 1965

Material examined. New material. ITALY • observations and photographs of 1 live specimen; Sardinia, Asinara National Park, Punta Tumbarino ; 41°02’17”N, 08°13’13”E; 29 Sep. 2014; coarse gravel with silt from a channel among rocks, at a depth of 29 m.

FRANCE • 1 serially sectioned specimen; Banyuls-sur-Mer , Cap l’Abeille; 42°28’40”N, 3°09’19”E; 20 Jul. 2007; at the border between the coralligenous and sand zones, clean sand with some silt from a depth of 24 m; UH VIII.4.23 • 4 whole mounts, 8 serially sectioned specimens; Banyuls-sur-Mer, Le Troc, La Peleteuse; 42°28’42”N, 3°08’52”E; 31 Jul. 2007; at the transition of rocks to sandy substrate, clean sand from a depth of 15 m; UH VIII.4.11–VIII.4.22 • 4 whole mounts and 4 serially sectioned specimens; Banyuls-sur-Mer, Cap l’Abeille; 42°28’40”N, 3°09’19”E; 11 Jul. 2008; at the border between the coralligenous and sand zones, clean sand with some silt from a depth of 22 m; UH VIII.4.07–VIII.4.10 & UH VIII.4.24–VIII.4.27 • 1 whole mount; Cerbère, Les Chambres; 42°26’43”N, 3°10’09”E; 9 Jun. 2013; fine sand with a lot of silt; UH VIII.4.41 .

SPAIN • 4 whole mounts; Catalonia, Blanes ; 41°40’04”N, 2°47’19”E; 20 Jul. 2012; sand patches on the north side of a rock with footpath, coarse, clean sand with organic debris; UH VIII.4.30–VIII.4.33 .

Known distribution. Porto Paone, Gulf of Naples, Italy ( Boaden 1965). Archipel de Riou, Provence-Alpes-Côte d’Azur, France ( Brunet 1968).

Remarks. Our observations correspond to those of earlier authors ( Boaden 1965; Brunet 1968). Live specimens measure up to 1.8 mm and have a slightly reddish pigmentation. The mouth is situated a short distance behind the proboscis. The proboscis is armed with a pair of slender hooks (15–16 μm) and bears a pair of thin, non-sclerotised sidepieces (12–13 μm). A single subterminal haptic girdle is present near the caudal body end.

A single testis is present near the posterior end of the pharynx. From the testes, a pair of vasa deferentia leads to the paired seminal vesicles. Each seminal vesicle is 120–150 μm long. The seminal vesicles enter the proximal end of the male copulatory apparatus. The copulatory bulb contains a prostatic vesicle, 70–80 μm long, followed distally by a relatively short ejaculatory duct. The distal part of the ejaculatory duct is sclerotised to form an unarmed, tubular cirrus. Distally, the cirrus is provided with a number of fine, sclerotised ridges. According to Boaden (1965), only this part of the cirrus is eversible.

A strongly muscular vagina externa is present in the posterior part of the body. It consists of a thin-walled canal, leading from the vaginal opening (shortly behind the common genital pore), to a thick-walled proximal section, which is divided into three chambers. Conspicuous radial striations are present on the vaginal wall in this part. Proximally, the vagina opens into a thin-walled bursa, which lies adjacent to the single ovary.