The worm-shaped, shell-less Caudofoveata is one of the least known groups of molluscs. As early-branching molluscs, the lack of high-quality genomes hinders our understanding of their evolution and ecology. Here, we report a high-quality chromosome-scale genome of Chaetoderma sp. combining PacBio, Illumina, and high-resolution chromosome conformation capture sequencing. The final assembly has a size of 2.45 Gb, with a scaffold N50 length of 141.46 Mb, and is anchored to 17 chromosomes. Gene annotations showed a high level of accuracy and completeness, with 23,675 predicted protein-coding genes and 94.44% of the metazoan conserved genes by BUSCO assessment. We further present 16S rRNA gene amplicon sequencing of the gut microbiota in Chaetoderma sp., which was dominated by the chemoautotrophic bacteria (phylum Gammaproteobacteria). This chromosome-level genome assembly presents the first genome for the Caudofoveata, which constitutes an important resource for studies ranging from molluscan evolution, symposium, to deep-sea adaptation.

蠕虫形、无壳的 Caudofoveata 是已知最少的软体动物群之一。作为早期分枝的软体动物，缺乏高质量的基因组阻碍了我们对它们的进化和生态学的理解。在这里，我们报道了 Chaetoderma sp. 的高质量染色体规模基因组，结合了 PacBio、Illumina 和高分辨率染色体构象捕获测序。最终组装的大小为 2.45 Gb，支架 N50 长度为 141.46 Mb，并锚定在 17 条染色体上。基因注释显示出高水平的准确性和完整性，通过 BUSCO 评估预测了 23,675 个蛋白质编码基因和 94.44% 的后生动物保守基因。我们进一步提出了毛皮病菌属肠道微生物群的 16S rRNA 基因扩增子测序，该菌种以化学自养细菌 （Gammaproteobacteria） 门为主。这种染色体水平的基因组组装展示了 Caudofoveata 的第一个基因组，它构成了从软体动物进化、研讨会到深海适应等研究的重要资源。