On a collection of freshwater shrimps (Crustacea Decapoda Caridea) from the Philippines, with descriptions of five new species

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

Caridina 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.

Phylogenetic and biogeographic relationships of subterranean and surface genera of Australian Atyidae (Crustacea : Decapoda : Caridea) inferred with mitochondrial DNA

The biogeographic and phylogenetic relationships of six of the eight Australian genera of freshwater shrimp from the family Atyidae were investigated using mitochondrial 16S rDNA and cytochrome oxidase I sequences. Previous studies on two of the epigean genera (Caridina, Paratya) indicate that Australian species have strong links to congenerics from outside, with Australian members of Paratya being monophyletic and Caridina polyphyletic. The present study found that the endemic Australian epigean genus Australatya forms a strong clade with Pacific ‘Atya-like’ genera (Atyoida, Atyopsis), and that the endemic Australian epigean genus Caridinides falls within a clade containing Caridina species from the Australian ‘indistincta’ group. The two hypogean genera included in this study (Parisia, Pycnisia) form a strong clade in all analyses, implying an Australian subterranean speciation. The possibility of a relationship between Parisia/Pycnisia and an Australian Caridina species may have implications for the monophyly of the highly disjunct genus Parisia (Australia, Madagascar, Philippines). Parisia may descend from local Caridina species and represent convergent morphologies.