Torotaia Haas, 1939

Zhang, Le-Jia & von Rintelen, Thomas, 2021, The neglected operculum: a revision of the opercular characters in river snails (Caenogastropoda: Viviparidae), Journal of Molluscan Studies 87 (2), pp. 1-14 : 13

Torotaia Haas, 1939

Examined species: Torotaia mainitensis (Bartsch, 1907) ( Figs 4F , 5F , 7F ).

Remarks: The operculum of Torotaia is distinct from that of most genera, but similar to that of Celetaia in the following characters: a large, smooth and shiny nuclear region, which is sometimes surrounded by concentric veins, and a thin marginal region. However, the operculum of Torotaia is more fragile and thinner, with the apex being noticeably more acute than in Celetaia .

Figures

Figure 4. Interior surface of opercula of the viviparid species studied. A. Celetaia persculpta. B. Ussuripaludina ussuriensis. C. Sinotaia angularis. D. Anularya mansuyi. E. Anularya bicostata. F. Torotaia mainitensis. G. Neothauma tanganyicense. H. Bellamya phthinotropis. I. Bellamya trochlearis. J. Idiopoma umbilicata. K. Idiopoma dissimilis. L. Filopaludina luzonica. M. Filopaludina martensi. N. Filopaludina bengalensis. O. Filopaludina gigantea. P. Trochotaia trochoides. ƍ. Taia naticoides. R. Taia shanensis. S. Notopala ampullaroides. T. Angulyagra cf. polyzonata. Scale bar: 5 mm.

Figure 5. Exterior surface of opercula of the viviparid species studied. A. Celetaia persculpta. B. Ussuripaludina ussuriensis. C. Sinotaia angularis. D. Anularya mansuyi. E. Anularya bicostata. F. Torotaia mainitensis. G. Neothauma tanganyicense. H. Bellamya phthinotropis. I. Bellamya trochlearis. J. Idiopoma umbilicata. K. Idiopoma dissimilis. L. Filopaludina luzonica. M. Filopaludina martensi. N. Filopaludina bengalensis. O. Filopaludina gigantea. P. Trochotaia trochoides. ƍ. Taia naticoides. R. Taia shanensis. S. Notopala ampullaroides. T. Angulyagra cf. polyzonata. Scale bar: 5 mm.

Figure 7. Shells of the viviparid species studied. A. Celetaia persculpta. B. Ussuripaludina ussuriensis. C. Sinotaia angularis. D. Anularya mansuyi. E. Anularya bicostata. F. Torotaia mainitensis. G. Neothauma tanganyicense. H. Bellamya phthinotropis. I. Bellamya trochlearis. J. Idiopoma umbilicata. K. Idiopoma dissimilis. L. Filopaludina luzonica. M. Filopaludina martensi. N. Filopaludina bengalensis. O. Filopaludina gigantea. P. Trochotaia trochoides. ƍ. Taia naticoides. R. Taia shanensis. S. Notopala ampullaroides. T. Angulyagra cf. polyzonata. Scale bar: 10 mm.