Genetic characterization of the invasive serpulid <i>Ficopomatus</i> cf. <i>uschakovi</i> (Pillai, 1960) in a highly urbanized estuary in Texas, USA

Abstract Ficopomatus uschakovi has been reported in Galveston Bay (GB), Texas, USA, in taxonomic lists and studies of biofouling communities since 2017; however, after 2 years (from 2022 to 2024) of no observations of this species in the system, we report the first seasonal outbreak after the landfall of Hurricane Beryl in the summer of 2024, followed by 2 weeks of heavy rain, decreasing the salinity at the collection site. In this study, we provide the first genetic characterization of the specimens of F. cf. uschakovi from GB using mitochondrial cytochrome oxidase b DNA sequence data. Results demonstrated that specimens of F. cf . uschakovi in GB belong to the same genetic species as reported on both of coasts of Mexico, the Gulf coast of Florida, and Thailand. The presence of shared haplotypes suggests possible initial introduction from Asia and subsequent expansion of F. cf. uschakovi populations. The comparison of the morphological characters with reports from nearby localities showed a variation in the number of rows and spines on the operculum and in the tube colouration. This study highlights the importance of morphological and genetic analysis for reliable identification of invasive species, the need for wide geographical sampling, as well as examinations of the ecological drivers of F. cf. uschakovi outbreaks.