Luiz Simone just published a paper on the anatomy of Helicina variabilis, a typical member of the family Helicinidae, which occurs in Brazil.
“Helicina variabilis Wagner, 1827 (Neritimorpha, Helicinidae) is redescribed based on a sample collected in Nanuque, northern Minas Gerais, Brazil. The species description, previously based only on the shell, is expanded to the phenotypic features. The study revealed absorption of the internal shell whorls; a diaphragm muscle connected to the floor of the pallial cavity; a monoaulic pallial oviduct, with the female genital aperture inside the anal aperture, and the lack of a seminal receptacle and provaginal sac; and the pleural ganglia of the nerve ring connected with each other. The significance of these findings is discussed in the light of current taxonomic and phylogenetic knowledge”.
In the discussion of the paper Simone highlights the features that are interesting for the taxonomy of the group. The bursa copulatrix has a branched structure which may be useful in distinguishing different species. Comparisons are being made to related groups such as the Neritidae and to recent studies on the higher systematics of these groups. All in all an excellent paper, especially by the nicely detailed anatomical figures.
Simone, L.R.L., 2018. Phenotypic features of Helicina variabilis (Gastropoda: Neritimorpha) from Minas Gerais, Brazil. – Papéis Avulsos de Zoologia, 58: e20185832 (9 pp.). http://doi.org/10.11606/1807-0202/2018.58.32