Phylogeny of eunicida (Annelida) based on morphology of jaws

Hannelore Paxton*

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference proceeding contributionpeer-review

Abstract

Eunicida have a complex jaw apparatus with a fossil record dating back to the latest Cambrian. Traditionally, Eunicidae, Onuphidae, and Lumbrineridae were considered closely related families having labidognath maxillae, whereas Oenonidae with prionognath type maxillae were thought to be derived. Molecular phylogenies place Oenonidae with Eunicidae/Onuphidae, and Lumbrineridae as the most basal taxon. Re-evaluation of the jaw types based on morphology and ontogeny demonstrated that the labidognaths Eunicidae and Onuphidae have a closer relationship to the prionognath Oenonidae than was previously thought. Lumbrineridae are neither labidognath nor prionognath; therefore a new type, Symmetrognatha, is proposed. Homologies of jaw elements and considerations of functional aspects of the jaw apparatus are explored to present a hypothesis of the Eunicida phylogeny. The earliest fossils are of placognath and ctenognath types, lacking maxillary carriers. While the former are extinct, the latter are represented by the extant Dorvilleidae. The interpretation of relationships between the carrier-bearing families depends on whether the carriers are thought to have evolved once only or twice independently. The similarity of the carrier structure and their associated muscles suggests the former, placing the Lumbrineridae as sister to Eunicidae/Onuphidae and Oenonidae. However, the ontogeny of the eunicid/onuphid apparatus as well as its adult structure differ greatly from those of lumbrinerids, indicating that the lumbrinerid carriers may have evolved independently and earlier than in eunicids/onuphids and oenonids.

Original languageEnglish
Title of host publicationProceedings of the Ninth International Polychaete Conference
EditorsNJ Maciolek, JA Blake
Place of PublicationNew Zealand
PublisherMagnolia Press
Pages241-264
Number of pages24
ISBN (Print)9781869773731
DOIs
Publication statusPublished - 2009
Event9th International Polychaete Conference - Portland, Montenegro
Duration: 12 Aug 200717 Aug 2007

Publication series

NameZoosymposia
PublisherMAGNOLIA PRESS
Volume2
ISSN (Print)1178-9913

Conference

Conference9th International Polychaete Conference
CountryMontenegro
CityPortland
Period12/08/0717/08/07

Keywords

  • maxillae
  • mandibles
  • ontogeny
  • ctenognath
  • placognath
  • labidognath
  • prionognath
  • symmetrognath
  • fossils
  • scolecodonts

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