Chromosome-level assembly for the complex genome of land hermit crab Coenobita brevimanus.

Land hermit crabs are a group of shell-carrying crabs that have evolved remarkable terrestrial adaptations in behavior, morphology, physiology, and biochemistry. However, the genetic mechanisms underlying these adaptations remain unclear. In addition, usually it is very difficult to get good genome assemblies for crustaceans. In this study, we managed to assemble the first chromosome-level genome for a land hermit crab (Coenobita brevimanus) with careful manual curation. The final assembly spans 4.74 Gb, with the contig N50 of 1.75 Mb and scaffold N50 of 42.95 Mb, encompassing 117 chromosomes that account for 96.54% of the genome. The evaluations including genome BUSCO (95.26%), Merqury qv (35.88) and the mapping ratio of pair-end short reads (99.48%) showed the high-continuity of C. brevimanus genome assembly, making it the genome with the highest quality in crustaceans with genome size bigger than 3 Gb. The availability of this chromosome-scale genome of crustaceans represents a valuable resource for the land hermit crab, which represents an independent water-to-land transition evolutionary event in the animal kingdom.