Abstract
The present investigation focuses on population genetic structure analysis of the endangered giant clam species
Tridacna maxima
across part of the Red Sea, with the main aim of assessing the influence of postulated potential barriers to gene flow (i.e., particular oceanographic features and marked environmental heterogeneity) on genetic connectivity among populations of this poorly dispersive bivalve species. For this purpose, a total of 44 specimens of
T. maxima
were collected from five sampling locations along the Saudi Arabian coast and examined for genetic variability at the considerably variable mitochondrial gene cytochrome c oxidase I (COI). Our results revealed lack of population subdivision and phylogeographic structure across the surveyed geographic spectrum, suggesting that neither the short pelagic larval dispersal nor the various postulated barriers to gene flow in the Red Sea can trigger the onset of marked genetic differentiation in
T. maxima
. Furthermore, the discerned shallow COI haplotype genealogy (exhibiting high haplotype diversity and low nucleotide diversity), associated with recent demographic and spatial expansion events, can be considered as residual effect of a recent evolutionary history of the species in the Red Sea.