1. Gene-sequence analysis reveals at least three species hidden in Zausodes arenicolus
Erin Easton
November 13, 2008

2. Zausodes-complex species
Bouck et al., (1999) split genus and described new species
Five species occur locally
Species co-occur

3. Z. arenicolus and Z. septimus
Occur in an implausible number of habitats
Have been used in ecological studies (including local studies)

4. Verification important
If Bouck et al. are correct, then
(1) ecological studies should be redone,
(2) Zausodes species are less attractive for ecological studies, and
(3) the new morphological characters provide additional tools for taxonomic discrimination

5. Verify with DNA-sequence data
Presence of phenotypic plasticity
Absence of morphological differentiation
Identification of taxonomic groups that need additional taxonomic revision
Increase in confidence of species’ boundaries with a combined morphological and DNA-sequencing approach

6. Purpose
To use DNA-sequence methods to test the reliability of the species’ boundaries proposed by Bouck et al. (1999) for specimens collected in the northeastern Gulf of Mexico.
To test whether evidence of unrecognized species exists using DNA-sequence data.

7. Samples Five sites Five species
Specimens identified by morphological characters

8. Obtaining sequences DNA was extracted
Target genes were amplified and sequenced

9. Analyze sequences Align sequences
Develop neighbor-joining and maximum likelihood trees

10. Compare and re-evaluate
Compare morphological and DNA-sequence data with respect to species’ boundaries
Identify whether additional morphological characters were overlooked

11. Cytochrome b ML tree
Bayesian over bootstrap

12. Morphological re-evaluation
Three morphotypes observed in Zausodes arenicolus
Differences in P5 endopod setae

16. Conclusions
Combined DNA-sequence and morphological data suggest at least three species hidden in Zausodes arenicolus.
Bouck et al.’s characters supported but species were still overlooked.
Sequence data reveal specimens that require additional taxonomic focus.

17. Thank you

18. Cytochrome b divergences

19. 18S ML tree Z. arenicolus are divided into four clades
Least divergent cytb clades form one 18S clade

20. 18S divergences

21. Future plans
Apply combined DNA-sequence and morphological analysis to deep-sea harpacticoids to better understand their ranges and genetic diversity.