Phylogenetic positions of some species of the genus Macrobrachium Bate, 1868 (Orustacea, Decapoda, Palaemonidae) in Sri Lanka

Abstract

Macrobrachium species, are an economically important freshwater prawn group in Sri Lanka. These species are recognized by their local names and many synonyms can be found for one species. Identification of taxonomic positions and species boundaries within the genus is important to obtain reliable information for application in aquaculture and biodiversity conservation programmes. Approximately 471bp partial sequences from mitochondrial 16S rRNA using seven Macrobrachium species were collected during the present study. Six of them were collected from the southern part of Sri Lanka and their phylogenetic positions among the relevant species that have been recorded within the region were determined. The analysis resulted in five clades, of which three showed monophyletic lineages (M. australe group, M. latimanus group, and M. latidactylus group). M. malcolmsonii is in a sister clade to M. rosenbergii while M. scabriculum joined with M. idae. The estimated intraspecific nucleotide divergence level varied from 0-6.07% while it varied from 5.21-10.84% at the interspecific level. The phylogenetic positions of the samples recorded within the region are discussed.