Integrative taxonomy helps separate four species of freshwater shrimps commonly overlooked as Caridina longirostris (Crustacea : Decapoda : Atyidae) on Indo-West Pacific islands

International audienceCaridina longirostris H. Milne Edwards, 1837 described from specimens supposedly from La Macta River near Oran, Algeria, is an emblematic species of the ‘C. nilotica complex’. Until now this species was thought to have a wide distribution in the Indo-Pacific region. Recently, numerous specimens identified as C. longirostris were collected from various Indo-West Pacific localities. In the context of integrative taxonomy, both old and newly collected specimens were morphologically and genetically studied. Four species allied to C. longirostris are here identified: C. appendiculata Jalihal & Shenoy, 1998, C. brevidactyla Roux, 1920, C. gracilipes De Man, 1892 and C. meridionalis Roux, 1926. Detailed re-descriptions of these four species are given as well as their geographical and ecological distributions. Caridina nilotica var. brevidactyla is revalidated as the species C. brevidactyla, and C. coulaborensis Richard & Clark, 2014, C. fritzi Richard & Clark, 2014 and C. solamulieres Richard & Clark, 2014 are considered junior synonyms of C. meridionalis. The position of these species in the troublesome ‘C. nilotica complex’ is clarified and some species are synonymised. A key is provided to facilitate identification