title: Molecular clocks indicate turnover and diversification of modern coleoid cephalopods during the Mesozoic Marine Revolution.
abstract: Coleoid cephalopod molluscs comprise squid, cuttlefish and octopuses, and represent nearly the entire diversity of modern cephalopods. Sophisticated adaptations such as the use of colour for camouflage and communication, jet propulsion and the ink sac highlight the unique nature of the group. Despite these striking adaptations, there are clear parallels in ecology between coleoids and bony fishes. The coleoid fossil record is limited, however, hindering confident analysis of the tempo and pattern of their evolution. Here we use a molecular dataset (180 genes, approx. 36 000 amino acids) of 26 cephalopod species to explore the phylogeny and timing of cephalopod evolution. We show that crown cephalopods diverged in the Silurian-Devonian, while crown coleoids had origins in the latest Palaeozoic. While the deep-sea vampire squid and dumbo octopuses have ancient origins extending to the Early Mesozoic Era, 242 ± 38 Ma, incirrate octopuses and the decabrachian coleoids (10-armed squid) diversified in the Jurassic Period. These divergence estimates highlight the modern diversity of coleoid cephalopods emerging in the Mesozoic Marine Revolution, a period that also witnessed the radiation of most ray-finned fish groups in addition to several other marine vertebrates. This suggests that that the origin of modern cephalopod biodiversity was contingent on ecological competition with marine vertebrates.
authors.affiliation: School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
authors.forename: Alastair R
authors.identifier: http://orcid.org/0000-0001-8045-2856
authors.initials: AR
authors.lastname: Tanner
authors.affiliation: Earth and Planetary System Science, Department of Natural History Sciences, Hokkaido University, Sapporo, Japan.
authors.forename: Dirk
authors.initials: D
authors.lastname: Fuchs
authors.affiliation: Natural History Museum of Denmark, Øster Voldgade 5-7, 1350 Copenhagen, Denmark.
authors.forename: Inger E
authors.initials: IE
authors.lastname: Winkelmann
authors.affiliation: Natural History Museum of Denmark, Øster Voldgade 5-7, 1350 Copenhagen, Denmark.|Trace and Environmental DNA Laboratory, Department of Environment and Agriculture, Curtin University, Perth, Western Australia, Australia.|NTNU University Museum, Norwegian University of Science and Technology, Trondheim, Norway.
authors.forename: M Thomas P
authors.initials: MT
authors.lastname: Gilbert
authors.affiliation: Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA.
authors.forename: M Sabrina
authors.initials: MS
authors.lastname: Pankey
authors.affiliation: Natural History Museum of Denmark, Øster Voldgade 5-7, 1350 Copenhagen, Denmark.
authors.forename: Ângela M
authors.initials: ÂM
authors.lastname: Ribeiro
authors.affiliation: Department of Biological Sciences, University of Alabama, Box 870344, Tuscaloosa, AL 35487, USA.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Kocot
authors.affiliation: Department of Biological Sciences, Auburn University, Auburn, AL 36830, USA.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Halanych
authors.affiliation: Department of Ecology, Evolution, and Marine Biology, University of California, Santa Barbara, CA 93106, USA.
authors.forename: Todd H
authors.initials: TH
authors.lastname: Oakley
authors.affiliation: Natural History Museum of Denmark, Øster Voldgade 5-7, 1350 Copenhagen, Denmark.|Department of Biology, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark.
authors.forename: Rute R
authors.initials: RR
authors.lastname: da Fonseca
authors.affiliation: School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.|School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
authors.forename: Davide
authors.identifier: http://orcid.org/0000-0003-0949-6682
authors.initials: D
authors.lastname: Pisani
authors.affiliation: School of Biological Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK jakob.vinther@bristol.ac.uk.|School of Earth Sciences, University of Bristol, Life Sciences Building, 24 Tyndall Avenue, Bristol BS8 1TQ, UK.
authors.forename: Jakob
authors.identifier: http://orcid.org/0000-0002-3584-9616
authors.initials: J
authors.lastname: Vinther
mesh_terms: D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D049830:Cephalopoda / Q000145:classification*; D005580:Fossils; D010802:Phylogeny
keywords: Cephalopoda; molecular clocks; molecular phylogenetics; phylogenomics