Published online by Cambridge University Press: 10 August 2017
The definitions of terebellid genera have caused considerable confusion. Some genera, such as Pista Malmgren, 1866, are clearly not monophyletic and the need to revise them is widely accepted. A phylogenetic analysis of genus level morphological characters within the Axionice/Pista complex and other Terebellidae with large lateral lobes revealed two well defined groups; these differed in the arrangement of different forms of lateral lobes on segments 1–3, the shape of the branchiae, structure of the ventral pads and, if present, the origin of the manubrium on the uncini. One of the groups includes the type species of Pista; the other includes the type species of Axionice and almost all the other genera whose taxonomic status is discussed in this paper (Betapista, Eupistella, Lanice, Loimia, Paraxionice) which we propose to treat as its junior synonyms. Three other genera – Lanicides, Lanicola and Scionella – did not fall within these two groups; they are accepted as distinct. A complete list of species of Axionice and Pista is provided; 39 species currently included in Pista should be moved to Axionice, thus Axionice includes at least 94 species. Many authors’ descriptions of the type species of Pista (Amphitrite cristata Müller, 1776) conflict with the original description. Amphitrite cristata s. str. has been described as a new species: Scionella lornensis Pearson, 1969 and the type species of a new genus: Pistella Hartmann-Schröder, 1996. Scionella lornensis is here considered a junior synonym of Amphitrite cristata. Redescriptions of the type species of Axionice and Pista are provided.