title: Depth as a driver of evolution in the deep sea: Insights from grenadiers (Gadiformes: Macrouridae) of the genus Coryphaenoides.
abstract: Here we consider the role of depth as a driver of evolution in a genus of deep-sea fishes. We provide a phylogeny for the genus Coryphaenoides (Gadiformes: Macrouridae) that represents the breadth of habitat use and distributions for these species. In our consensus phylogeny species found at abyssal depths (>4000m) form a well-supported lineage, which interestingly also includes two non-abyssal species, C. striaturus and C. murrayi, diverging from the basal node of that lineage. Biogeographic analyses suggest the genus may have originated in the Southern and Pacific Oceans where contemporary species diversity is highest. The abyssal lineage seems to have arisen secondarily and likely originated in the Southern/Pacific Oceans but diversification of this lineage occurred in the Northern Atlantic Ocean. All abyssal species are found in the North Atlantic with the exception of C. yaquinae in the North Pacific and C. filicauda in the Southern Ocean. Abyssal species tend to have broad depth ranges and wide distributions, indicating that the stability of the deep oceans and the ability to live across wide depths may promote population connectivity and facilitate large ranges. We also confirm that morphologically defined subgenera do not agree with our phylogeny and that the Giant grenadier (formerly Albatrossia pectoralis) belongs to Coryphaenoides, indicating that a taxonomic revision of the genus is needed. We discuss the implications of our findings for understanding the radiation and diversification of this genus, and the likely role of adaptation to the abyss.
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK; Section of Ichthyology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA 94118, USA. Electronic address: michellergaither@gmail.com.
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Gaither
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK; Istituto Nazionale Biostrutture e Biosistemi, Viale delle Medaglie d'Oro 305, Rome, Italy; Department of Earth, Environment and Life Sciences, University of Genoa, Corso Europa 26, 16132 Genoa, Italy.
authors.forename: Biagio
authors.initials: B
authors.lastname: Violi
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
authors.forename: Howard W I
authors.initials: HWI
authors.lastname: Gray
authors.affiliation: Marine Scotland-Science, 375 Victoria Rd, Aberdeen AB11 9DB, Scotland, UK.
authors.forename: Francis
authors.initials: F
authors.lastname: Neat
authors.affiliation: Department of Oceanography, University of Hawaii at Manoa, 1000 Pope Rd, Honolulu, HI 96822, USA.
authors.forename: Jeffrey C
authors.initials: JC
authors.lastname: Drazen
authors.affiliation: Florida State University Coastal and Marine Laboratory, 3618 Hwy 98, St. Teresa, FL 32358, USA.
authors.forename: R Dean
authors.initials: RD
authors.lastname: Grubbs
authors.affiliation: Virginia Institute of Marine Science, PO Box 1346, Gloucester Point, VA 23062, USA.
authors.forename: Adela
authors.initials: A
authors.lastname: Roa-Varón
authors.affiliation: Halmos College of Natural Sciences and Oceanography, Nova Southeastern University, 8000 North Ocean Drive, Dania Beach, FL 33004, USA.
authors.forename: Tracey
authors.initials: T
authors.lastname: Sutton
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK. Electronic address: a.r.hoelzel@durham.ac.uk.
authors.forename: A Rus
authors.initials: AR
authors.lastname: Hoelzel
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D001267:Atlantic Ocean; D045304:Cytochromes c / Q000145:classification / Q000235:genetics / Q000378:metabolism; D004247:DNA / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D017753:Ecosystem; D048388:Gadiformes / Q000145:classification* / Q000235:genetics; D018398:Homeodomain Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism; D009792:Oceans and Seas; D010140:Pacific Ocean; D010802:Phylogeny; D058974:Phylogeography; D012335:RNA, Ribosomal / Q000145:classification / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
chemical_list: D018398:Homeodomain Proteins; D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S; D045304:Cytochromes c; D004247:DNA
keywords: Abyssal; Deep-sea fishes; Hydrostatic pressure; Macrouridae; Phylogenetics; Rattails