Ruthenica, 2019, vol. 29, No. 2: 115-120. © Ruthenica, 2019 Published online March 5, 2019 http: www.ruthenica.com Mysterious Erepta odontina (Morelet, 1851) (Gastropoda, Pulmonata, Helicarionidae) Anatoly SCHILEYKO A.N. Severtsov Institute of Ecology and Evolution of Russian Academy of Sciences, Leninsky prospect 33, Moscow 119071, RUSSIA. E-mail
[email protected] ABSTRACT. Anatomical study of five specimens of an 50220” it is indicated that the material was collected endemic species of the Mauritius Island, Erepta odon- in 1906. tina showed that within one population disappearing The anatomical study was performed by tradi- of additional organs of the reproductive tract (epiphal- tional methods of manual dissection under the bino- lic caecum, penial caecum, penial appendix, flagellum cular microscope Olympus SZ. and retractor of penis) occurs in four different combina- Abbreviations in figures: E – epiphallus, EC – tions. It is significant that the shells of all five speci- mens were practically identical. It is assumed that the epiphallic caecum, F – flagellum, FO – free oviduct, described phenomenon has a mutagenic nature and is P – penis, PC – penial caecum, PS – penis sheath, regarded as a rare (if not unique) case of reduction (up PR – retractor of penis, Pro – prostate, RS – to complete disappearance) of additional organs within reservoir of spermatheca, V – vagina, VD – vas one population. deferens. Introduction Systematic part The terrestrial malacofauna of the Mascarene Helicarionidae Bourguignat, 1883 Islands, including the fauna of the Mauritius island, Ereptinae Godwin-Austen, 1908 is studied quite fully mainly due to two extensive works performed in the early twentieth century Godwin-Austen, 1908: 432; Schileyko, 2002: 1234 (in Ari- [Godwin-Austen, 1908; Germain, 1921].