Phylogenetic analyses of Chaetopteridae (Annelida)

Abstract

Phylogenetic relationships within Chaetopteridae were assessed using parsimony cladistic analysis of 43 external morphological characters and molecular phylogenetic analysis of three genes: mitochondrial cytochrome oxidase subunit I DNA (COI) and nuclear 28S and 18S ribosomal DNA. The group currently comprises four accepted genera: Chaetopterus Cuvier, Spiochaetopterus Sars, Phyllochaetopterus Grube and Mesochaetopterus Potts, with 97 available species names. We selected 79 species and one subspecies with adequately detailed data for morphological comparison. Sixteen additional unidentified chaetopterid species were included to enhance representation of the morphological and genetic diversity of the family. The morphological matrix was coded chiefly from the original descriptions, as well as revisions, type specimens and newly collected specimens. Chaetopteridae was monophyletic in the molecular phylogeny, and united by a number of morphological features, including a single pair of grooved peristomial palps, three morphologically distinct tagmata (A, B, C) and the presence of stout, modified cutting chaetae on anterior chaetiger 4 (A4). Chaetopterus and Mesochaetopterus formed well‐supported sister clades based on sequence data; however, the reciprocal monophyly of these genera was not supported by morphological data. Spiochaetopterus and Phyllochaetopterus were paraphyletic/polyphyletic as currently defined, and the status of these and other available generic names is discussed.