New lineages within the Malagasy freshwater crab fauna: Agora n. gen. for Thelphusa goudoti H. Milne Edwards, 1853, and a phytotelmic new species of Malagasya Cumberlidge & Sternberg, 2002 (Brachyura: Potamonautidae: Deckeniinae)

Abstract

AbstractNew molecular and morphological analyses of the relationships of 77 specimens of potamonautid freshwater crabs collected from all parts of Madagascar support the monophyly of the island’s freshwater crab fauna and verify most of the existing taxa. The phylogenetic tree identified several new lineages that represent four new genera and 10 new species, and found Foza Reed & Cumberlidge, 2006 to be paraphyletic. The present work is the first of a series of articles reporting on these discoveries that provide an improved understanding of the relationships between the endemic potamonautid species found on this tropical island. We describe a new species of Malagasya Cumberlidge & Sternberg, 2002 from a phytotelmic habitat in northeast Madagascar, and establish Agoragen. nov. to accommodate Thelphusa goudoti H. Milne Edwards, 1853. Both of these new taxa are recognized based on combinations of morphological characters and molecular data. The new species of Malagasya is distinguished from the other two species of this genus, which are illustrated here for comparative purposes. Agora goudotin. comb. is endemic to Madagascar, and is compared with and distinguished from the eight other genera of freshwater crabs occurring in that country.