The radular cusp formulae of Neotricula aperta (Gastropoda: Pomatiopsidae): taxonomic questions

Abstract

The polytypic snail Neotricula aperta (Temcharoen, 1971) is found in the Mekong River of Northeast Thailand and southern Laos (α- and γ- strains) and in the Mul River of Northeast Thailand (β-strain). The γ -strain is known to be the intermediate host for human schistosomiasis in southern Laos and Cambodia. Populations were sampled in Northeast Thailand and cusp formulae recorded for all four types of taenioglossate teeth of the radula. Unlike earlier studies, which considered only the α- and γ-strains, the present work involved all three strains. Observations of tooth cusping patterns agree well with those of earlier studies of the α- and γ-strains but disagree with those of Temcharoen (1971) when describing the holotype of Lithoglyphopsis aperta (N. aperta). The implications of these findings for the taxonomy of N. aperta are discussed. Radular formulae do not appear to be useful additional characters in the distinction of the three strains of N. aperta. Radular data call for resampling of the type population in southern Laos and a comparative study of the related sympatric snail Manningiella conica Temcharoen, 1971.

Keywords:

• Neotricula Aperta Radula Taxonomy