A molecular contribution to the controversial taxonomical status of some freshwater snails (Caenogastropoda: Rissooidea, Cochliopidae) from the Central Andes desert to Patagonia

Abstract

ABSTRACT. For over 40 years malacologists have been discussing the taxonomical status of Heleobia species, an enigmatic genus from Cochliopidae family (Caenogastropoda: Rissooidea). As with other rissooidean families, the considerable character convergence and the paucity of anatomical synapomorphies has proved to be a problem in resolving cochliopid phylogenetic relations and establishing the validity of several nominal cochliopid species. Here we present a molecular contribution to solve the taxonomical status of one of the most abundant Southern South America cochliopid genera which has many endemic species. We report molecular evidence that supports three of the four Heleobia groups described for this region, the "australis", "parchappii" and "piscium" groups. The fourth, the "hatcheri" group, belongs not to Heleobia but to a different genus which itself should not be considered as part of the family Cochliopidae but closely related to genus Potamolithus Pilsbry & Rush, 1896.

Morphological and molecular analysis of cryptic native and invasive freshwater snails in Chile

“…In Chile, the presence of the mudsnail was first reported in 2014 and later in 2016 but the species was introduced earlier since it was confused with native species of the genus Heleobia in 2011 18,25,26 . Accurate identification of freshwater snails in the Southern Cone of South America becomes even more difficult considering that native species of Potamolithus have been confused with Heleobia 18,22,36–38 , for example “ Heleobia ” hatcheri (Pilsbry, 1911) and “ Heleobia ” santiagensis .…”

The genusPotamolithusPilsbry, 1896 (Gastropoda: Tateidae) on the Somuncurá Plateau, Patagonia, Argentina

“…and 'Heleobia' hatcheri), already mentioned by Koch et al (2015). 'Heleobia' hatcheri is a parthenogenetic species and has similarities in radular morphology (two or three pairs of basal cusps in the central tooth) as in species of Potamolithus and which are absent in typical species of Heleobia (Cochliopidae) in Argentina (Cazzaniga 2011;Koch et al 2015). 'Heleobia' sp.…”

“…Phylogenetic analyses confirm that the South American taxa included are members of the Tateidae, namely the species of Potamolithus and two species attributed to the cochliopid genus Heleobia Stimpson, 1865 ('Heleobia' sp. and 'Heleobia' hatcheri), already mentioned by Koch et al (2015). 'Heleobia' hatcheri is a parthenogenetic species and has similarities in radular morphology (two or three pairs of basal cusps in the central tooth) as in species of Potamolithus and which are absent in typical species of Heleobia (Cochliopidae) in Argentina (Cazzaniga 2011;Koch et al 2015).…”

“…comm., 2016). The Cochliopidae family is a well-defined clade being quite distinct from Tateidae (Wilke et al 2013;Koch et al 2015). Reproductive characters (morphology of the penis, prostate gland, as well as female characters) are considered of importance in defining tateid genera, but due to the small size of the samples, and because the specimens were not relaxed prior to fixation, it was not possible to make a more detailed anatomical study of the reproductive system.…”

Redescripción de Potamolithus supersulcatus Pilsbry, 1896 (Gastropoda, Tateidae) del sur de la cuenca Del Plata

“…De las 22 especies presentes en la Argentina, sólo cinco poseen descripciones anatómicas (completas o parciales) que incluyen órganos paleales, rádula, sistema reproductor y caracteres externos de las partes blandas (pigmentación cefalopedal y peneana): P. agapetus Pilsbry, 1911, P. buschii (Frauenfeld, 1865), P. lapidum (d 'Orbigny, 1835), P. rushii Pilsbry, 1896 y P. valchetensis Miquel, 1998 (Pilsbry, 1911;López Armengol, 1985Miquel, 1998). Desde el punto de vista genético solo se posee información para tres especies: P. ribeirensis (genes ribosomales 16S y 18S, y el gen mitocondrial citocromo c oxidasa subunidad I -COI-, Wilke et al, 2013); P. agapetus y P. buschii (COI, Koch et al, 2015).…”