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

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

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

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

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

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.

Samples Five sites Five species Specimens identified by morphological characters

Obtaining sequences DNA was extracted Target genes were amplified and sequenced

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

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

Cytochrome b ML tree Bayesian over bootstrap

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

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.

Thank you

Cytochrome b divergences

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

18S divergences

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