Redescription of Rhinus ciliatus (Gastropoda: Simpulopsidae), An Endemic Species from the Atlantic Rainforest in Brazil

ABSTRACT The genus Rhinus Martens, 1860, is represented in Brazil by about twenty species, which are predominantly found in the Atlantic rainforest, an endangered ecosystem with extraordinary biodiversity and high endemism. There is a dearth of detailed morphological data for most species of the genus Rhinus, and the anatomy of only a few species has been described. Rhinus ciliatus, an endemic species from southwestern Brazil, is known by few conchological traits and scarce anatomical data from the reproductive system and pallial cavity. In this study, we redescribe the shell morphology and soft body anatomy of Rhinus ciliatus in detail and compare the new data with known traits of other closely related species. Rhinus ciliatus is diagnosed by the following features: (i) transition from protoconch to teleoconch well marked; (ii) shell ovate-conic, accuminate; (iii) aperture sub-ovate, lip simple; (iv) kidney with granulated lamellae; and (v) marginal teeth with blunt spatula-shaped mesocones. The record of spermatophores for the genus is provided here for the first time.