A paper published last year describing a new species from Brazil is Simone & D’ávila. “Rectobelus levogyrus, a new species of subulinid, is described found in archaeological surveys in Amazon shell mounts (sambaquis) from Costa Marques, Rondônia, Brazil. It is the first sinistral subulinid species recorded in Brazil, and that is its main distinguishing character. A brief taxonomical treatment of the other congener species, R. rectus (Baker, 1927) (the type species, from Venezuela) and R. birabeni (Hylton Scott, 1946) (from Argentina) is included, with figures, as well as a discussion on the validity of the genus“.
The title of this papers is curious, citing two different subfamily names, which are both outdated as the Subulininae are now considered as belonging to the Achatinidae. This is a very difficult group as the species are separated on minor details which are often not consistently studied in larger series. Many species from the ‘subulinid’ group are supposed to have continuous growth, making size differences difficult to use as a taxonomic characteristic. Moreover, for many species anatomical and molecular data are lacking. In this paper Simone disagrees with the opinion of Hausdorf, who considered Rectobelus H.B. Baker. 1927 as a synonym of Ischnocion Pilsbry, 1907. The latter is placed on MolluscaBase in the subfamily Coeliaxinae. Thus there remains ample room for further research.
Simone, L.R.L. & D’ávila, 2019. The discovery of a sinistral Obeliscinae (Eupulmonata, Subulinidae) in Brazil, found in Amazon archaeological shell mounds of Rondônia. – Journal of Conchology 43(4): 327-336.