Three new species of the shrimp family Alpheidae from the south-western Indian Ocean (Decapoda: Caridea)

Three morphologically distinct new species of the caridean shrimp family Alpheidae are described, based on material collected in the south-western Indian Ocean. Arete cornutus sp. nov. is described based on several specimens of both sexes from southern and south-western Madagascar. This new species appears to be closest to A. acanthocarpus Miya & Miyake, 1968, differing from it and all other congeners by the presence of prominent supra-orbital teeth.

Synalpheus gloriosus sp. nov. is described on the basis of a single female holotype from Îles Glorieuses collected in the mesophotic zone at a depth range of 80– 147 m. One of the main diagnostic characters of S. gloriosus sp. nov. is the presence of a dense brush of gambarelloid setae on the minor cheliped, a very uncommon feature among Indo-West Pacific species of the genus Synalpheus Spence Bate, 1888. Finally, Alpheus ledoyeri sp. nov. from the A. brevirostris (Olivier, 1811) species group is described based on a single male holotype collected in north-western Madagascar in 1960.