School of Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Species boundaries in Zausodes-complex species (Copepoda : Harpacticoida : Harpacticidae) from the north-eastern Gulf of Mexico

Document Type

Article

Publication Date

8-30-2010

Abstract

Before 1999, the harpacticoid copepod species Zausodes arenicolus Wilson, 1932 was the subject of several ecological studies. Based on morphological evaluations of specimens from the north-eastern Gulf of Mexico, Bouck et al.’s (1999) taxonomic revision revealed three new species within what had been Z. arenicolus, making the ecological results suspect. Because harpacticoid copepods show convergent evolution and morphological stasis, Bouck et al.’s morphologically based approach may not have been sufficient. We have therefore re-evaluated their results using a combination of gene-sequencing and morphological methods. Partial mitochondrial cytochrome b (cytb) and 18S rRNA gene regions from individual Zausodes specimens found at five sites in the north-eastern Gulf of Mexico were separately analysed. Individuals of Zausodes septimus Lang, 1965 formed a single cytb gene-sequence clade, whereas Z. arenicolus individuals formed five. The uncorrected genetic divergences among these clades were 10 times those within them, providing evidence that each clade could be assigned to a different species. The 18S rDNA results support those from cytb. Subsequent morphological analysis revealed differences that will allow two clades of Z. arenicolus to be described as new species. Bouck et al. (1999) revealed some but not all of the species present.

Comments

Copyright CSIRO.

Publication Title

Invertebrate Systematics

DOI

https://doi.org/10.1071/IS09038

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