Molecular taxonomy of bumblebee gobies (Oxudercidae: Gobionellinae: Brachygobius) in Peninsular Malaysia

Tropical Asia is home to the brackish/freshwater fish genus Brachygobius (Teleostei: Oxudercidae: Gobionellinae), commonly known as bumblebee gobies due to the alternating black and yellow/whitish bands on their bodies. The taxonomy of these miniature fishes is insufficiently studied, making their identification difficult. Here, we examined the species diversity of bumblebee gobies in Peninsular Malaysia by applying two molecular markers: the “barcode” fragment of the cytochrome c oxidase subunit I (COI) gene and a fragment of the nuclear rhodopsin (rho) gene. Twenty-four COI sequences and 20 rho sequences of Brachygobius were newly determined, combined and analysed with available data from both within and outside Peninsular Malaysia. A species delimitation approach conservatively revealed nine species of Brachygobius in our dataset. Conflicts with the current morphology-based classification were identified. Brachygobius sabanus and Brachygobius doriae are not reciprocally monophyletic, while Brachygobius nunus and Brachygobius kabiliensis each represent a species complex. Four species occur in Peninsular Malaysia, which we identified as Brachygobius xanthomelas, Brachygobius sabanus, Brachygobius nunus, and Brachygobius cf. aggregatus. A photograph of a specimen from each species in Peninsular Malaysia, along with habitat and distribution information, is provided.