Oviparous reproduction of Vestia ranojevici moravica confirms taxonomic value of life history characters in carpathian clausiliids (Gastropoda: Pulmonata)

Based on five-year observation of 36 snails collected in the ?eladná valley (Moravia, Czech Republic) and their progeny reared in laboratory, it was found that Vestia ranojevici moravica (Brabenec, 1952) is oviparous. The oviparity in V. ranojevici is in line with the previous assumption of its reproductive strategy based on anatomical studies alone. It supports the separate position of the species in the genus Vestiaa (subgenus Brabenecia). V. ranojevici was kept at room temperature (18–25°C) between March and October; in winter snails were stored at 3°C. The egg-laying period started in late March, ca. 1 month after raising the temperature, and lasted till September, with one maximum in spring. In the laboratory the snails laid eggs in batches (usually 4–6 eggs, max 11) or singly. The number of batches per pair per season was 1–8; the corresponding number of eggs — 3–40. The eggs were gelatinous, with separate calcium carbonate crystals in the external envelope. The average egg size was 1.80 × 1.51 mm, but actual size and shape were highly variable: larger and more elongated eggs were produced mainly by laboratory reared animals. Freshly deposited eggs did not contain shelled embryos nor the reproductive tract of dissected individuals contained eggs. At room temperature the eggs hatched after ca. 14–16 days, then the shell growth lasted 20–29 weeks; the snails laid eggs 30 weeks after completion of shell growth indicating one-year life cycle under laboratory conditions. Adult individuals collected in the field reproduced during 4–5 consecutive years. Comparison of V. ranojevici reproduction to the results of breeding of other Carpathian clausiliids in the same laboratory shows that similar reproductive strategies may have evolved independently in different lineages of the group: both the oviparous and egg retaining species belong to the genera Vestia and Balea.