Unio delphinus isolate:BIV7592 Genome sequencing and assembly

Mussels of order Unionida are a group of strictly freshwater bivalves with nearly 1,000 described species widely dispersed across world freshwater ecosystems. Despite their fundamental ecological importance, they are highly threatened, with the highest records of extinction events within faunal taxa. Conservation is particularly concerning in species occurring in the Mediterranean biodiversity hotspot that are exposed to multiple anthropogenic threats including global warming predictions and water shortage. That is the case of the dolphin freshwater mussel Unio delphinus Spengler, 1793, endemic to the western Iberian Peninsula with recently strong population declines. To date, only four genome assemblies are available for the order Unionida and only one is from a species present in Europe. Here, we present the first genome assembly of the Iberian dolphin freshwater mussel Unio delphinus. We used the PacBio HiFi long-read technology to generate a highly contiguous genome assembly of U. delphinus. The assembly is 2.5 Gb long, possessing 1254 contigs with a contig N50 length of 10 Mbp. This is the most contiguous freshwater mussel genome assembly to date and is an essential resource for investigate the species biology and evolutionary history that ultimately will help to support conservation strategies.