Abstract
Agaricogonopus acrotrifoliolatus (Diplopoda: Spirostreptida) is the largest millipede species from China. Morphologically, it is characterized by a pair of prominent, fungiform gonopodal processes. Despite the ecological importance of Spirostreptida millipedes as key decomposers in soil ecosystems, genomic resources for this order are unavailable. Herein, we report the first chromosome-level genome assembly for Spirostreptida, represented by A. acrotrifoliolatus. The genome was constructed using a combination of PacBio HiFi long reads, Illumina short reads, and Hi-C sequencing. An initial assembly totaling 2.33 Gb was generated. Following Hi-C integration, 96.16% of the assembly was anchored to 11 pseudochromosomes, resulting in a final chromosome-level assembly of 2.24 Gb. The assembly exhibited high contiguity and completeness, with a scaffold N50 of 360.24 Mb and a 96.20% Benchmarking Universal Single-Copy Orthologs (BUSCO) score. Furthermore, 12,492 protein-coding genes and ~1.71 Gb (76.27%) of repetitive elements were identified. As the first reference genome for Spirostreptida, this assembly serves as a crucial genomic resource for advancing millipede genomics and evolutionary studies.