Crossing 5,000 km: A new species of Litarachna (Acari: Hydrachnidia) and the molecular connectivity of marine mites across the Indian Ocean

Pontarachnidae, the only family of Hydrachnidia inhabiting marine environments, utilize diverse dispersal mechanisms to inhabit broad geographic ranges. Recent molecular studies in semi-enclosed basins, such as the Mediterranean and Red Seas, have challenged the dispersal capabilities of species like Litarachna communis and Pontarachna punctulum, which were previously assumed to be widely distributed. In this study, we employed an integrative taxonomic approach to examine pontarachnid mites from the Indian Ocean. We describe a new species, Litarachna almiri sp. nov., identified from both Mauritius and Thailand. This disjunct distribution, spanning nearly 5,500 km, demonstrates that mites within the Indian Ocean, a fully integrated component of the global ocean system, can achieve significant long-distance dispersal. Additionally, we provide the first molecular confirmations for Litarachna denhami (Kenya), L. triangularis (Thailand), and Pontarachna cf. australis (Kenya). These findings emphasize the necessity of further taxonomic clarification and molecular analysis of type-locality material to resolve the distribution patterns of marine mites accurately.