Shell morphology of the freshwater snail Gundlachia ticaga (Gastropoda: Ancylidae) from four sites in Ilha Grande, southeastern Brazil

A study on the freshwater snail Gundlachia ticaga from Ilha Grande, Brazil, reveals significant phenotypic plasticity in shell morphology across four populations. Using nine morphometric characters and discriminant analysis, researchers found that shells from preserved and highly modified environments exhibited similar traits, challenging previous diagnostic criteria for identification. The findings highlight that narrower, elongated shells could be misidentified as Ferrissia, while broader, roundish shells might be confused with Burnupia. The absence of radial lines is not a reliable diagnostic feature, emphasizing the need to analyze apical micro-sculpture and soft parts for accurate species identification.

Lacerda, L. E. M., Miyahira, I. C., & Santos, S. B. (2011). Shell morphology of the freshwater snail Gundlachia ticaga (Gastropoda: Ancylidae) from four sites in Ilha Grande, southeastern Brazil. Zoologia (Curitiba, Impresso), 28(3), 334–342. https://doi.org/10.1590/s1984-46702011000300007