L. Forró szerk.: Miscellanea Zoologica Hungarica 7. 1992 (Budapest, 1992)

Varga, A.: A new Zonitarion from Western Africa (Mollusca, Urocyclidae)

A new Zonitanon from Western Africa (Mollusca, Urocyclidae) by A. Varga (Received February 24, 1992) Abstract: Zonitarion lefiniensis sp. n. (Mollusca, Urocyclidae) is described from Brazzaville (People's Republic of Congo). This medium-sized semi-slug differs considerably from the Zonitarion species known so far in the anatomical structure of its male copulatory organ. Key words: Zonitarion lefiniensis sp. n., Urocyclidae, Congo, Africa Zonitarion (Belonarion) lefiniensis sp. n. (Figs 1-24) Diagnosis. - A medium-sized semi-slug with dark pigmentation. Penis and sarcobelum both are surrounded by thin penis-sheath. Sarcobelum is simple, penis with a specially formed papilla. Sarcobelum is a bit longer than the penis. The penis bears a spherical caecum. External appearance. - The length of the holotype is 32 mm, preserved in alcohol. The body has a tan ground-colour, the side of the body is dark-coloured, ornamented by a net-like pigmentation, which becomes progressively more dense towards the caudal part. Foot, head and back are unicoloured bright. Behind the tentacles 1-1 dark bands spread towards the pneumostoma. The forepart of the mantle has a specific from, ornamented by dark pigment spots, the back area is greyish (Fig. 1). (The preservation in alcohol has weakened the colours, possibly the colours have faded away totally.) Shell. - (Holotype: Fig. 1, - para type: Figs 9, 17) - membranaceous, smooth, bright with a scarcely perceptible spiral sculpture. The shell has about two whorls. Measures: 13 x 9 mm (holotype). Genitalia. - (Holotype: Figs 2-5) - The free oviduct is shorter than the bursa copulatrix. The vagina is very short, its length is one fourth of the free oviduct. The bursa copulatrix has a rather large, cyst-formed sack and a pedunculus which is longer than this sack. The male copulatory organ (penis -I- sarcobelum) is clubformed, tapers off to its basic part slightly. Both are enclosed in a thin, penissheath, which becomes more and more thinner towards the apex of the organ, it can be scarcely percepted in the vicinity of the caecum. Penis and sarcobelum are not connected. Both of them possess different papillae. The papilla of sarcobelum is cambered, tapered. The penial papilla is rather complex, its base is expanded umbrella like, the side is wavy, slightly arched in the direction of the apex. Its apex broadens and levels out. This conical papilla sits on a long, cylindrical penis-section (in situ: Fig. 4, - papilla slightly elongated: Fig. 5). The penis with caecum is smaller than the sarcobelum. The penis has a spherical caecum which is settled at the proximity of the apex of the copulatory organ. The musculus retractor penis is short, it is inserted in the inner part of the caecum. Epiphallus is folded cambe-