Recently, Guzmán et al. reported on this species with the following abstract: “Omalonyx unguis (d’Orbigny, 1837) is a semi-slug inhabiting the Paraná river basin. This species belongs to Succineidae, a family comprising a few representatives in South America. In this work, we provide the first record for the species from Misiones Province, Argentina. Previous records available for Omalonyx in Misiones were identified to the genus level. We examined morphological characteristics of the reproductive system and used DNA sequences from cytochrome oxidase subunit I (COI) gene for species-specific identification. These new distributional data contribute to consolidate the knowledge of the molluscan fauna in northeastern Argentina”.
In the paper also figures of the shell and the genitalia are presented. The authors were likely unknown of the revisionary work of Vidigal et al. (2018), who showed that the correct name of this species is Omalonyx matheroni (Potiez & Michaud, 1835).
Guzmán, L.B. et al., 2018. First record of the semi-slug Omalonyx unguis (d’Orbigny, 1837) (Gastropoda, Succineidae) in the Misiones Province, Argentina. – CheckList 14 (5): 705-712.