The genus Potamolithus Pilsbry, 1896 (Gastropoda: Tateidae) on the Somuncurá Plateau, Patagonia, Argentina

ABSTRACT

The genus Potamolithus (Gastropoda: Tateidae) is endemic to South America where it is distributed mainly in the Ribeira, Itajaí-açú and Jacuhy Rivers in southern Brazil and the Uruguay River, part of the Paraná and Río de la Plata drainage systems. An exception to the pattern of distribution is Potamolithus valchetensis Miquel, 1998, which is endemic to the Valcheta Stream, Somuncurá Plateau, Patagonia, Argentina. Here we provide a review of Potamolithus from this plateau based on new samples and review of material deposited in collections. A new species, Potamolithus elenae, is named. The shell, head-foot, penis, pallial organs and radula are described. Differences between the new species and P. valchetensis include details in the shell, radula, body pigmentation and penis. A phylogeny using mitochondrial gene cytochrome c oxidase subunit I is provided which shows that Potamolithus is related to species in New Caledonia (Australasia), suggesting that the Tateidae has a Gondwanan distribution.

KEYWORDS:

• Anatomy
• COI
• conchology
• endemic
• freshwater snails
• Gondwanan distribution
• taxonomy

Acknowledgements

We thank Melina Velasco and Federico Kacoliris for the donation of material and the staff of the malacological collection of the Museo Argentino de Ciencias Naturales ‘Bernardino Rivadavia’ (MACN) for their generosity in allowing review of the type of Potamolithus valchetensis material. We thank Sergio Miquel for the authorisation of Figure 1. We are grateful to Prof. Emma Galatti for English editing. We are especially grateful to Dr. Winston F. Ponder whose critical reading and comments helped improve this manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.