Redescription of the bigeye chimaera, Hydrolagus macrophthalmus de Buen, 1959 (Chondrichthyes: Chimaeriformes), with a genetic characterization of the species


Hydrolagus macrophthalmus de Buen, 1959 is a little known chimaerid species from the southeastern Pacific Ocean. At the time of its description, it was the only chimaeroid species known from the region; however, there now are four other Hydrolagus species known from the area. Hydrolagus macrophthalmus is distinct from other species in the area based on the following characters: an undulated second dorsal fin with peaks on the anterior and posterior regions, a long curved first dorsal fin spine that extends past the origin of the second dorsal fin when laid flat, and uniform dark brown color with a light spot on middle of the second dorsal fin that extends onto the body below it. Genetic sequencing of the NADH2 gene was used to distinguish H. macrophthalmus from other known species in the region. This species is herein re-described and compared to four sympatric species: H. alphus, H. melanophasma, H. mccoskeri, and H. trolli. The redescription of this species will improve identification and aid in the taxonomic resolution of Southeastern Pacific Ocean chimaeras. A key to species of Hydrolagus in the Southeastern Pacific Ocean is provided.

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Change history

  • 24 July 2019

    The authors regret to have published the wrong Fig. 4 of this manuscript.


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The authors would like to thank Dominique Didier (Millersville University) for general discussions related to this project, and James Lindholm (CSU Monterey Bay) and the students of the Pacific Shark Research Center including Paul Clerkin, Justin Cordova, Maddie Harris, Kelsey James, Melissa Nehmans, Amber Reichert, and Marty Schmidt who helped with data collection and/or manuscript review. Finally, Matthew Jew would like to extend the sincerest thanks to his parents Kathy and Fulton Jew for fostering a passion for science from a very young age.


This project was supported in part by the National Science Foundation (NSF) Collaborative Research: Jaws and Backbone: Chondrichthyan Phylogeny and a Spine for the Vertebrate Tree of Life (DEB 1132229). This project was funded by the Undergraduate Research Opportunities Center (UROC) at California State University, Monterey Bay.

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Correspondence to Matthew Jew.

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All applicable international, national, and/or institutional guidelines for the care and use of animals were followed by the authors. Tissues were collected under the Institutional Animal Care and Use Committee (IACUC) Non-Living Tissue Protocol 2014D.

Sampling and field studies

All necessary permits for sampling and observational field studies have been obtained by the authors from the competent authorities and are mentioned in the Acknowledgements, if applicable.

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Communicated by R. Thiel

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Jew, M., Ebert, D.A., Kemper, J.M. et al. Redescription of the bigeye chimaera, Hydrolagus macrophthalmus de Buen, 1959 (Chondrichthyes: Chimaeriformes), with a genetic characterization of the species. Mar Biodiv 49, 1605–1614 (2019).

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  • Chimaeridae
  • Hydrolagus
  • Holotype
  • Chile
  • Identification
  • NADH2