Speciation in the deep : genomics and morphology reveal a new species of beaked whale Mesoplodon eueu

This work was supported by ONR grants N000141613017 to E.L.C. and N.A. and N00014-18-1-2808 to C.S.B.; funds from the NMNH Rebecca G. Mead and James G. Mead Marine Mammal Endowment, NSF (USA) grant no. DEB-1457735 to M.S.S., P.A.M. and J.G.; Brothers Hartmann Foundation grant no. AB28148 to M.T.O.; NMFS, BOEM, and USA Navy funding to D.Ch. under the Atlantic Marine Assessment Program for Protected Species. M.L.M. was funded under the Marie Skłodowska-Curie grant agreement no 801199; E.L.C. by a Rutherford Discovery Fellowship from the Royal Society of New Zealand Te Apārangi. Irish Whale and Dolphin Group Cetacean Stranding scheme is part-funded by the National Parks and Wildlife Service. The deep sea has been described as the last major ecological frontier, as much of its biodiversity is yet to be discovered and described. Beaked whales (ziphiids) are among the most visible inhabitants of the deep sea, due to their large size and worldwide distribution, and their taxonomic diversity and much about their natural history remain poorly understood. We combine genomic and morphometric analyses to reveal a new Southern Hemisphere ziphiid species, Ramari's beaked whale, Mesoplodon eueu, whose name is linked to the Indigenous peoples of the lands from which the species holotype and paratypes were recovered. Mitogenome and ddRAD-derived phylogenies demonstrate reciprocally monophyletic divergence between M. eueu and True's beaked whale (M. mirus) from the North Atlantic, with which it was previously subsumed. Morphometric analyses of skulls also distinguish the two species. A time-calibrated mitogenome phylogeny and analysis of two nuclear genomes indicate divergence began circa 2 million years ago (Ma), with geneflow ceasing 0.35–0.55 Ma. This is an example of how deep sea biodiversity can be unravelled through increasing international collaboration and genome sequencing of archival specimens. Our consultation and involvement with Indigenous peoples offers a model for broadening the cultural scope of the scientific naming process. Publisher PDF