Two new species of Thaumastus (Gastropoda: Pulmonata: Orthalicidae: Bulimulinae) from the state of Minas Gerais, Brazil

Abstract

Two new species of Thaumastus (Thaumastus) from the state of Minas Gerais, southeastern Brazil, are described. They are diagnosed and characterized by the morphology of the shell and soft parts and compared with Brazilian species of the subgenus Thaumastus s.s. Martens, 1860. Thaumastus (T.) parvus sp. nov. is similar to T. (T.) baixoguanduensis Pena, Coelho & Salgado, 1996 but can be distinguished by the smaller size, smaller number of plates in the jaw, different number of follicle groups in the ovotestis and form of the fertilization complex. Thaumastus (T.) caetensis sp. nov. is similar to T. (T.) largillierti (Philippi, 1845) but differs by the width and the contour of the parietal side of the shell aperture. T. (T.) caetensis is also closer to Thaumastus (T.) baixoguanduensis but can be distinguished by the smaller dimensions (height, width and number of protoconch whorls), the lack of a transversal light band on the body whorl, the jaw with smaller number of plates, and the radula with 35 teeth. In the soft parts, this new species differs also in the number of follicle gatherings in ovotestis, fertilization complex with globose shape, and penian retractor muscle terminally and laterally attached to flagellum

Keywords

• Mollusca
• morphology
• Orthalicoidea
• taxonomy