Reconciling taxonomy and phylogeny in the bristleworm family Eunicidae (polychaete, Annelida)

Abstract

Zanol, J., Halanych, K.M., Fauchald, K. (2014). Reconciling taxonomy and phylogeny in the bristleworm family Eunicidae (polychaete, Annelida). -Zoologica Scripta, 43, 79-100. Eunicid annelids inhabit diverse marine habitats worldwide, have ecological and economic importance and have been pictured in the news as giant predator worms. They compose a traditional stable taxon recently supported as monophyletic but characterized by plesiomorphies. Most genera within the family have been recovered as paraphyletic in previous studies. We present a phylogenetic hypothesis for eunicid based on molecular (COI, 16S rDNA, 18S rDNA) and morphological data (213 characters), including an explicit attempt to account for serial homology. Eunicidae as well as monophyletic genera Marphysa sensu stricto and Lysidice is redefined based on synapomorphies. Nematonereis is synonymized to Lysidice. Leodice and Nicidion are resurrected to name monophyletic groups including species previously included in Eunice and Marphysa sensu lato. Traditional diagnostic characters such as the absence/presence of peristomial cirri, lateral antennae and branchiae are homoplasies and not informative at the generic level. Different coding of traditional characters (i.e. articulation of prostomial appendages) and novel characters of prostomial features and regionalization of the body support the monophyly of the family and genera level clades. Thus, the phylogenetic hypothesis presented here and the evolution of characters provided background information for taxonomic changes yielding evolutionary meaningful classification and diagnoses for the family and genera.

Six genetically distinct clades of Palola (Eunicidae, Annelida) from Lizard Island, Great Barrier Reef, Australia

“…Doing this would probably add resolution to the base of the phylogenetic tree. One of the markers used by Zanol et al (2010Zanol et al ( , 2014 for eunicid phylogeny is 18S ribosomal RNA (18S rRNA). However, examination of the 18S rRNA sequences from these studies deposited in Genbank revealed that they were all identical and thus would be too conserved to resolve phylogenetic relationships within Palola.…”

“…Trees were sampled every 100 generations from the posterior distribution after the burn-in period and a 50% majority rule consensus tree was generated. Leodice antennata was chosen as the outgroup based on the analyses by Zanol et al (2010Zanol et al ( , 2014. Additional eunicid taxa representing Lysidice, Nicidion and Marphysa were included to test the monophyly of Palola.…”

“…Due to this simplified morphology, not many features are available for species-level identification, since many of the characters commonly used in other eunicids, such as the shape, coloration and onset of the subacicular hooks or the branching pattern of the branchiae along the body, are inapplicable. According to the recent molecular phylogenetic analyses by Zanol et al (2010Zanol et al ( , 2014, Palola is monophyletic within Eunicidae.…”

New species and new records of eunicids (Polychaeta, Eunicidae) from Taiwan

“…During the late 20 th and early 21 th century, the latter two genera were still regarded as synonyms of Eunice (Fauchald 1992;Zanol et al 2010). On the basis of a recent molecular phylogeny study on the family Eunicidae Berthold, 1827, Zanol et al (2014) suggested Leodice and Nicidion are valid genera and subsequently transferred some of Eunice spp. to these newly re-erected genera.…”

“…It was once used interchangeably with Leodice Savigny in Lamarck, 1818 (Zanol et al 2014), and Nicidion Kinberg, 1865 was considered as a subgenus of Eunice (Fauchald 1970). During the late 20 th and early 21 th century, the latter two genera were still regarded as synonyms of Eunice (Fauchald 1992;Zanol et al 2010).…”