Morphological and ontogenetic stratification of abyssal and hadal Eurythenes gryllus sensu lato (Amphipoda:Lysianassoidea) from the Peru-Chile Trench

Ryan M. Eustace, Heather Ritchie, Niamh M. Kilgallen, Stuart B. Piertney, Alan J. Jamieson*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)


The globally ubiquitous lysianassoid amphipod, Eurythenes gryllus, has been shown to consist of multiple genetically distinct cryptic taxa, with depth considered a major driver of speciation and morphological divergence. Here we examine morphological variation of E. gryllus sensu lato through a continuous depth distribution that spans from abyssal (3000-6000 m) into hadal depths (>6000 m) in the Peru-Chile Trench (SE Pacific Ocean). Three distinct morphospecies were identified: one was confirmed as being E. magellanicus (4602-5329 m) based on DNA sequence and morphological similarity. The other two morphologically distinct species were named based upon depth of occurrence; Abyssal (4602-6173 m) and Hadal (6173-8074 m). The three Eurythenes morphospecies showed vertical ontogenetic stratification across their bathymetric range, where juveniles were found shallower in their depth range and mature females deeper. Potential ecological and evolutionary drivers that explain the observed patterns of intra and inter-specific structure, such as hydrostatic pressure and topographical isolation, are discussed.

Original languageEnglish
Pages (from-to)91-98
Number of pages8
JournalDeep Sea Research Part I: Oceanographic Research Papers
Early online date12 Jan 2016
Publication statusPublished - 1 Mar 2016

Bibliographical note

We thank Nichola Lacey (University of Aberdeen) for support and Kevin Mackenzie and Lucy Wight (University of Aberdeen) from assistance using the SEM microscope. We thank the Chief Scientist, Captain, Crew and Company of the German FS Sonne SO209, Dr Kota Kitazawa from the Atmosphere and Ocean Research Institute (AORI), and the University of Tokyo for the their support in this work. AJJ and HR are supported by the Marine Alliance for Science and Technology for Scotland (MASTS) funded by the Scottish Funding Council (Ref: HR09011) and contributing institutions. N.M.K.'s participation was funded through the NIWA Capability Fund (Project CF113354). We also thank the anonymous reviewers for their helpful comments on the manuscript.


  • Amphipoda
  • Deep sea
  • Eurythenes gryllus
  • Hadal zone
  • Lysianassoidea
  • Morphology
  • Speciation


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