Chromosome-Level Genome Assembly and Annotation of the Freshwater Snail Sinotaia angularis (O. F. Müller, 1774)

Sinotaia angularis is a freshwater viviparid snail with limited genomic resources. Here, we report a chromosome-level reference genome generated using PacBio HiFi sequencing and Hi-C scaffolding, with mitochondrial marker -based screening (16S rRNA and COI (cox1)) and phylogenetic analysis supporting the taxonomic assignment. A total of 74.08 Gb of HiFi reads were obtained, providing approximately 65.7-fold genome coverage. The final assembly spans 1.127 Gb, with a scaffold N50 of 141.87 Mb and a GC content of 34.47%. Hi-C scaffolding anchored 978.89 Mb (86.85% of the assembly) onto eight chromosome-level scaffolds. BUSCO analysis using the mollusca_odb10 dataset recovered 86.9% complete orthologs from the genome assembly. Repeat annotation identified 378.75 Mb of repetitive sequences (33.60% of the genome), with unclassified repeats and LTR elements as the dominant components. Gene annotation predicted 22,232 protein-coding genes, 209 tRNAs, 72 rRNAs, 88 snRNAs, and 10 snoRNAs. Functional annotation assigned database support to 155,611 predicted proteins or isoforms, corresponding to 98% of the total protein set. CAZy annotation identified 5371 carbohydrate-active enzyme entries, suggesting broad carbohydrate-processing potential. This genome provides a reference resource for comparative genomics, chromosome evolution, repeat dynamics, gene-family evolution, and freshwater adaptation studies in Viviparidae.