Discrete genetic boundaries of three Streblospio (Spionidae, Annelida) species and the status of S. shrubsolii

Abstract

Spionid polychaetes are a dominant component of benthic assemblages in marine and estuarine habitats and are important in assessing ecological function and integrity. Ecological and biogeographic studies rely upon the ability to distinguish between morphologically similar species, as well as knowledge of evolutionary relationships between species. Unfortunately, differentiating between congeneric species of spionids can be challenging thereby potentially creating mistakes in scientific investigations. For example Streblospio contains three recognized species (S. benedicti, S. shrubsolii, S. gynobranchiata) with few distinguishing morphological characters. Herein, we use ∼500 bases of the mitochondrial cytochrome c oxidase subunit 1 gene (COI) to investigate the status of S. shrubsolii relative to other Streblospio. COI has previously been used to distinguish North American Streblospio benedicti and S. gynobranchiata. Results indicate all three Streblospio species are reciprocally monophyletic with S. shrubsolii basal to a well-supported S. benedicti/S. gynobranchiata clade.

Keywords:

• Annelida
• COI
• mtDNA
• phylogeny
• poecilogony
• Polychaeta

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

Acknowledgements

The authors wish to thank Jim Blake, Vasily Radashevsky, and Mary Peterson for their helpful comments in the completion of this manuscript. The comments and efforts of Paula Chainho from the Instituto de Oceanografia of the Universidade de Lisboa are gratefully acknowledged. This work was made possible by the NSF WormNet Grant EAR-0120646. This work is AU Marine Biology Program contribution #36.

Notes

Published in collaboration with the University of Bergen and the Institute of Marine Research, Norway, and the Marine Biological Laboratory, University of Copenhagen, Denmark

1. Webster's original description of Streblospio benedicti should be cited in this work as Webster (1879). The type locality for S. benedicti is Great Egg Harbor, NJ USA. The confusion in the literature arises due to the fact that the 1879b paper was reprinted in 1880 with different pagination and a different volume number. The following references

• Webster HE. 1879a. Annelida Chætopoda of the Virginian coast. Transactions of the Albany Institute 9:202–269.

• Webster HE. 1879b. The Annelida Chætopoda of New Jersey. Annual Reports of the New York State Museum of Natural History 32:101–128. (Streblospio first published here.)

• Webster HE. 1880. The Annelida Chætopoda of New Jersey. Annual Reports of the New York State Museum of Natural History 39:128–159. (This is a reprint of the 1879 paper with added plates.)