Molecular phylogeny of Mexican species of freshwater prawn genus Macrobrachium (Decapoda: Palaemonidae: Palaemoninae)

Molecular phylogenetic analyses of 16 species of the freshwater prawn genus Macrobrachium from Mexico are presented. The phylogenetic reconstructions are based on partial sequences from 16S rDNA mitochondrial gene. The results show a clear separation of the species with extended larval development (ED) from those with abbreviated larval development (AD). Within the ED clade, the species of the Olfersii Group clustered together, which is in agreement with their morphological similarity, whereas the position of the three pairs of geminate species within this clade suggests different origins. Five Mexican species are grouped into a single clade suggesting a common origin in a species with few larval stages and relatively large eggs. The estimated time of evolutionary divergence suggests that the ED and AD clades diverged in the Middle Eocene; the three geminate pairs differentiated at different times, and the species of the AD group originated during the Early Pliocene.