A reference genome for the rough limpet Lottia scabra, an intertidal species from the northeastern Pacific.

The rough limpet, Lottia scabra, a generalist grazer in the upper intertidal zone of the northeastern Pacific, spans the California Transition Zone, where southern warm-water populations gradually replace northern cold-water ones, providing a valuable system for studying genomic adaptation. We present the first high-quality reference genome for L. scabra, making a significant advancement over previously available molecular resources for both L. scabra and the genus Lottia. We used PacBio HiFi long reads and Omni-C chromatin proximity sequences to assemble a genome comprising 70 scaffolds spanning 414.08 Mb, with an N50 of 5.33 Mb and a completeness of 96.4% single-copy ortholog genes. The assembly contains 10 chromosome-scale scaffolds, consistent with previously published karyotypes of sister taxa. This high-quality genome will enhance our understanding of the mechanisms underlying adaptation to environmental differences and species responses to environmental change, with implications for coastal biodiversity conservation.