Sequence data on four genes suggest nominal Gerres filamentosus specimens from Nayband National Park in the Persian Gulf represent two distinct species

Sequence data of a recent COI barcoding study on fish from the Nayband National Park in the Persian Gulf showed relatively high sequence divergence among nominal Gerres filamentosus specimens. The sequences grouped into two clusters, signaling the possible existence of cryptic species. The clustering pattern was corroborated by results of 16S rDNA sequencing. We investigated the hypothesis that G. filamentosus specimens represent cryptic species by inspecting sequences of Cyt b, an additional mitochondrial gene, and 28S rDNA a well-conserved nuclear marker. Based on sequence data of four genes (COI, 16S rDNA, 28S rDNA and Cyt b), we propose that nominal Gerres filamentosus specimens from Nayband National Park represent a species complex comprising two distinct but closely related species. The observation of a large deletion in the highly conserved 28S rDNA gene of a representative specimen of one of the G. filamentosus clusters was considered particularly informative. G. filamentosus occurs through vast ranges of the Indo-Pacific, from the east coast of Africa to Japan and Australia. More comprehensive sampling and additional morphological and molecular analysis of members of this nominal species is required