RT Journal Article T1 Gene pools in rockpools: coastal Ochthebius beetles across the western Mediterranean A1 García Meseguer, Antonio José A1 Muñoz Gabaldón, Irene A1 Abellán, Pedro A1 Villastrigo, Adrián A1 Mirón Gatón, Juana María A1 Millán, Andrés A1 Velasco, Josefa AB Supratidal rockpools, ecotones between land and sea, are fragmented habitats with extreme environmental fluctuations, housing unique species like Ochthebius beetles. These beetles, which exhibit broad geographical ranges and cryptic lineages in the western Palaearctic, serve as a model for studying population genetics. This study investigates the population genetic diversity and structure of three co-occurring species in the western Mediterranean, and the impact of geographic and environmental distances, coastal features, and marine barriers on gene flow in two of them. The study reveals low genetic diversity in all three species, with similar observed heterozygosity values. Ochthebius quadricollis exhibited higher diversity and notable population variations, being the only species with marked genetic structure. For this species, AMOVA indicated significant genetic variation among the predefined groups, which was higher than within groups. We found an association between genetic differentiation and geographical distances but only for O. quadricollis. Our research highlights great connectivity and gene flow among supratidal rockpool populations of aquatic beetles, probably due to multiple passive dispersal pathways operating at different spatial scales. The three species exhibit varying degrees of genetic differentiation along the Iberian coast, confirming the genetic patterns observed in previous studies with less precise markers and larger scales. However, some discrepancies were noted, especially regarding the role of the Ibiza Channel as a barrier to genetic flow in O. quadricollis, where isolation by distance appears to be crucial. While marine currents were initially hypothesized to influence connectivity, our results suggest that their contemporary role in shaping recent gene flow is limited compared to that of geographic distance. PB Oxford Academy SN 0024-4082 YR 2025 FD 2025-12-01 LK https://hdl.handle.net/20.500.14352/132155 UL https://hdl.handle.net/20.500.14352/132155 LA eng NO García-Meseguer, A. J., Muñoz, I., Abellán, P., Villastrigo, A., Mirón-Gatón, J. M., Millán, A., & Velasco, J. (2025). Gene pools in rockpools: Coastal Ochthebius beetles across the western Mediterranean. Zoological Journal of the Linnean Society, 205(4), zlaf173. https://doi.org/10.1093/zoolinnean/zlaf173 DS Docta Complutense RD 18 mar 2026