UC San Diego

Chaetopterus Cuvier, 1830 is a genus of annelid worms, currently with 23 accepted species. These worms typically reside in parchment-like tubes and are highly effective filter feeders. This study presents the discovery and description of three new species of Chaetopterus based on their morphological and genetic data: Chaetopterus jeffgranti sp. nov. from Papua New Guinea, Chaetopterus harlancheni sp. nov. from the South Sandwich Islands, and Chaetopterus arcanatubus sp. nov. from Western Australia. Phylogenetic analyses using mitochondrial cytochrome oxidase subunit (COI), 18S and 28S nuclear ribosomal DNA sequences, along with complete mitochondrial genomes, were conducted to elucidate the evolutionary relationships within the genus. Additionally, this research refines the geographical distribution of Chaetopterus antarcticus using the COI haplotypes of 24 samples, confirming the resurrection of the species from Chaetopterus variopedatus and contributing to resolving the issue with the cosmopolitan Chaetopterus variopedatus species complex. The study also explores mitochondrial genomic diversity, confirming the presence of an intron within the COI gene of the Chaetopterus species. These findings substantially broaden the molecular resources available for Chaetopterus and provide insight for future research.