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Morphological studies of lymnaeid snails from the human fascioliasis endemic zone of Bolivia

Abstract:

The taxonomic position of the Lymnaeidae from the Bolivian Altiplano has been unclear. On the basis of conchological characters, some authors reported two species from this area, Lymnaea viatrix and L. cubensis while others, considering also anatomical characters, considered L. viatrix as a synonym of L. cubensis. More recent studies demonstrated genetic identity between the Bolivian lymnaeids and L. truncatula from the Iberian Peninsula. Populations recognized as L. cubensis correspond to a distinct genetic group, but genetic information was not available for L. viatrix. In the light of these genetic results, a morphometric study of both the shell (using Raupian parameters) and male reproductive system was carried out of L. cubensis from Cuba (type locality), Dominican Republic, Guadeloupe and Venezuela, and of L. truncatula from Bolivia, France, Portugal, Spain and Morocco. Syntypes of L. viatrix from Argentina (var. A. ventricosa) and specimens of L. viatrix (var. B. elongata) from the type locality, Peru, were also studied (conchological characters only). The conchological study showed the presence of a large amount of variability between populations. This variability was not congruent with genetic results. A large amount of variability was also found using anatomical characters of the male reproductive system and all of them clearly separate L. cubensis from L. truncatula independently from geographical origin. Thus anatomical characters, unlike conchological parameters, do differentiate taxonomic species inferred from genetic studies.