Unravelling the taxonomy and identification of a problematic group of benthic fishes from tropical rivers (Gobiidae: Glossogobius)

Abstract

Flathead gobies (genus Glossogobius) include c. 40 small-to medium-sized benthic fishes found primarily in freshwater habitats across the Indo-Pacific, having biodiversity value as well as cultural and economic value as food fishes, especially in developing countries. To help resolve considerable confusion regarding the identification of some of the larger-growing Glossogobius species, a systematic framework was established using nuclear genetic markers, mitochondrial DNA barcoding and phenotypic evidence for a geographically widespread collection of individuals from the waterways of tropical northern Australia. Species boundaries and distribution patterns were discordant with those previously reported, most notably for the tank goby Glossogobius giuris, which included a cryptic species. Genetic divergence was matched with accompanying unique visual characters that aid field identification. Additional taxonomic complexity was also evident, by comparison with DNA barcodes from international locations, suggesting that the specific names applicable for two of the candidate species in Australia remain unresolved due to confusion surrounding type specimens. Although flathead gobies are assumed to be widespread and common, this study demonstrates that unrealised taxonomic and ecological complexity is evident, and this will influence assessments of tropical biodiversity and species conservation. This study supports the need for taxonomic studies of freshwater fishes to underpin management in areas subject to significant environmental change. K E Y W O R D Saquatic environments, environmental management, molecular genetics, freshwater fishes, northern Australia | INTRODUCTIONA sound systematic framework is a vital first step in documenting and protecting biodiversity, especially in little-explored, biologically rich or rapidly changing aquatic environments (Bortolus, 2008;Lundberg et al., 2000). Taxonomic programmes to distinguish and describe species are essential for research, legislation and management (Allendorf, 2017;Wheeler, 1995). Confused identity, confounded ecological data and unrealised extinction are likely without them. Data quality assurance and quality control to verify species identificationincluding imaging, lodgement of voucher specimens, molecular genetic screening and specific investigations of problematic groupsshould,

Genetic diversity and divergence among native and translocated populations of the golden flathead goby Glossogobius aureus (Gobiiformes: Gobiidae) in Philippine lakes

“…This study did not require ethical approval because the used fish samples are commonly sold as food fish in the markets and were already dead when purchased. The specimens were identified morphologically based on Akihito and Meguro [ 1 ], Hammer et al [ 56 ], and Hoese and Hammer [ 57 ]. Furthermore, the molecular delimitation of Glossogobius species in each of the lakes was carried out through DNA barcoding and was published in a separate paper (see reference 10 for details).…”

Comparing Approaches to Specimen Identification using Neotropical Freshwater Fishes in the Barra del Colorado Wildlife Refuge, Costa Rica

“…However, DNA barcoding may be more challenging for Neotropical fishes given the reliance of this method on morphology for initial identification of voucher specimens and the known inconsistencies in public barcode databases. (Meier et al, 2008;Fort et al, 2021;Grant et al, 2021;Hammer et al, 2021). An integrative approach can aid in the identification of Neotropical freshwater fishes.…”

Multi-gene insights into the taxonomy and conservation of Tasmania’s galaxiid fishes

“…not stand-alone DNA barcoding), which have routinely found compelling evidence for additional candidate species in most genera surveyed, e.g. Cairnsichthys (Hammer et al 2018), Gadopsis (Hammer et al 2014;Unmack et al 2017), Galaxias (Adams et al 2014), Galaxiella (Unmack et al 2012), Glossamia (Cook et al 2017), Glossogobius (Hammer et al 2021a), Hypseleotris (Unmack et al 2019), Melanotaenia (Unmack 2016;Hammer et al 2019a), Mogurnda (Cook et al 2011;Adams et al 2013), Nannoperca (Unmack et al 2011(Unmack et al , 2013, Philypnodon (Hammer et al 2019b), Pseudogobius (Hammer et al 2021b), Retropinna (Hammer et al 2007;Unmack et al 2022), Syncomistes (Shelley et al 2018) and Tandanus (Jerry 2008).…”