First reference genome for the family Disteniidae (Coleoptera: Chrysomeloidea), the sister lineage to all longhorned beetles (Cerambycidae).

Disteniidae, the closest extant sister lineage to the longhorned beetles (Cerambycidae), represents a phylogenetically important yet understudied group within the phytophagous superfamily Chrysomeloidea. Here, we present the first chromosome-level reference genome for the family Disteniidae, generated for the East Asian species Distenia gracilis (Blessig) using PacBio HiFi long reads, Pore-C chromatin conformation capture, and Illumina RNA sequencing. The assembled genome spans 1.89 Gbp and is among the largest of all cerambycid genomes sequenced to date, with a scaffold N50 of 203.5 Mbp, 97.1% of which is anchored to 10 chromosome-scale scaffolds. Synteny analysis identified chromosome 10 as the X chromosome and corroborates the deep conservation of the X chromosome across Coleoptera. Repetitive elements constitute 66.8% of the genome, and 77,131 protein-coding genes were predicted, of which 33,643 were functionally annotated. As the first genomic resource for Disteniidae, this reference genome provides a critical comparative framework for investigating the origins of wood-feeding evolution and for elucidating the evolutionary history of horizontally-acquired plant cell wall-degrading enzymes in Chrysomeloidea.