Radix rufescens (J. E. Gray, 1822) (Gastropoda: Lymnaeidae), a new species for Oman and Arabian Peninsula

The fauna of freshwater gastropods of the Arabian Peninsula, a desert land, is neither rich nor extensively studied. Only five species of the family Lymnaeidae have been recorded from this subcontinent so far. In February 2023, a few specimens of Radix rufescens (J. E. Gray, 1822) have been collected from the stream at Wadi Tiwi, NE Oman. The shell, female part of the reproductive organs, prostate, paraeputium and phalloteca are presented. Cytochrome oxidase subunit I (COI) sequences confirmed the assignment of these specimens to R. rufescens, known from Nepal, Bangladesh, and Myanmar, not from the Arabian Peninsula. Either R. rufescens is the sixth lymnaeid species inhabiting Arabia, or at least some of the records of R. natalensis (Krauss, 1848), whose shells are hardly discernible from the ones of R. rufescens, should be interpreted as misidentified R. rufescens. Thousands of years of the trade relations between Oman and India suggest accidental transportation of this snail by trade vessels.