Abstract
In this paper, we use molecular phylogenetics, micro-CT scanning, and morphological analyses to describe a new species of goby, Pascua marecoralliensis, and demonstrate that the genus Pascua is distinct from Hetereleotris, as supported by five diagnostic characters, including modified basicaudal scales and reduced sensory papillae patterns. Phylogenetic analysis places Pascua as sister to the Gobiodon group, while Hetereleotris forms a separate clade. The new species, P. marecoralliensis, differs from congeners in fin ray counts, cephalic pore patterns, and head morphology and exhibits unique live colouration. Additionally, we reclassify Hetereleotris readerae and H. sticta as Pascua readerae and P. sticta based on shared genus-specific traits. The distribution of Pascua spans the southern Pacific, suggesting a relict lineage or undiscovered diversity in the genus. This work underscores the importance of integrative taxonomic approaches for resolving cryptic diversity in gobioid fishes and highlights the need for further sampling in understudied regions.