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Qiao T, King B, Long JA, Ahlberg PE, Zhu M. Early Gnathostome Phylogeny Revisited: Multiple Method Consensus. PLoS One 2016; 11:e0163157. [PMID: 27649538 PMCID: PMC5029804 DOI: 10.1371/journal.pone.0163157] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Accepted: 09/02/2016] [Indexed: 12/02/2022] Open
Abstract
A series of recent studies recovered consistent phylogenetic scenarios of jawed vertebrates, such as the paraphyly of placoderms with respect to crown gnathostomes, and antiarchs as the sister group of all other jawed vertebrates. However, some of the phylogenetic relationships within the group have remained controversial, such as the positions of Entelognathus, ptyctodontids, and the Guiyu-lineage that comprises Guiyu, Psarolepis and Achoania. The revision of the dataset in a recent study reveals a modified phylogenetic hypothesis, which shows that some of these phylogenetic conflicts were sourced from a few inadvertent miscodings. The interrelationships of early gnathostomes are addressed based on a combined new dataset with 103 taxa and 335 characters, which is the most comprehensive morphological dataset constructed to date. This dataset is investigated in a phylogenetic context using maximum parsimony (MP), Bayesian inference (BI) and maximum likelihood (ML) approaches in an attempt to explore the consensus and incongruence between the hypotheses of early gnathostome interrelationships recovered from different methods. Our findings consistently corroborate the paraphyly of placoderms, all 'acanthodians' as a paraphyletic stem group of chondrichthyans, Entelognathus as a stem gnathostome, and the Guiyu-lineage as stem sarcopterygians. The incongruence using different methods is less significant than the consensus, and mainly relates to the positions of the placoderm Wuttagoonaspis, the stem chondrichthyan Ramirosuarezia, and the stem osteichthyan Lophosteus-the taxa that are either poorly known or highly specialized in character complement. Given that the different performances of each phylogenetic approach, our study provides an empirical case that the multiple phylogenetic analyses of morphological data are mutually complementary rather than redundant.
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Affiliation(s)
- Tuo Qiao
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
| | - Benedict King
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
| | - John A. Long
- School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia
| | - Per E. Ahlberg
- Department of Organismal Biology, Evolutionary Biology Centre, Uppsala University, Norbyvägen, Uppsala, Sweden
| | - Min Zhu
- Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, China
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52
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Giles S, Darras L, Clément G, Blieck A, Friedman M. An exceptionally preserved Late Devonian actinopterygian provides a new model for primitive cranial anatomy in ray-finned fishes. Proc Biol Sci 2016; 282:20151485. [PMID: 26423841 PMCID: PMC4614771 DOI: 10.1098/rspb.2015.1485] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Actinopterygians (ray-finned fishes) are the most diverse living osteichthyan (bony vertebrate) group, with a rich fossil record. However, details of their earliest history during the middle Palaeozoic (Devonian) ‘Age of Fishes' remains sketchy. This stems from an uneven understanding of anatomy in early actinopterygians, with a few well-known species dominating perceptions of primitive conditions. Here we present an exceptionally preserved ray-finned fish from the Late Devonian (Middle Frasnian, ca 373 Ma) of Pas-de-Calais, northern France. This new genus is represented by a single, three-dimensionally preserved skull. CT scanning reveals the presence of an almost complete braincase along with near-fully articulated mandibular, hyoid and gill arches. The neurocranium differs from the coeval Mimipiscis in displaying a short aortic canal with a distinct posterior notch, long grooves for the lateral dorsal aortae, large vestibular fontanelles and a broad postorbital process. Identification of similar but previously unrecognized features in other Devonian actinopterygians suggests that aspects of braincase anatomy in Mimipiscis are apomorphic, questioning its ubiquity as stand-in for generalized actinopterygian conditions. However, the gill skeleton of the new form broadly corresponds to that of Mimipiscis, and adds to an emerging picture of primitive branchial architecture in crown gnathostomes. The new genus is recovered in a polytomy with Mimiidae and a subset of Devonian and stratigraphically younger actinopterygians, with no support found for a monophyletic grouping of Moythomasia with Mimiidae.
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Affiliation(s)
- Sam Giles
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
| | - Laurent Darras
- 313 Rue Nationale, Appt. 96, Nœux-les-Mines 62290, France
| | - Gaël Clément
- Centre de Recherches sur la Paléobiodiversité et les Paléoenvironnements (CR2P, UMR 7207), Sorbonne Universités, MNHN, CNRS, UPMC-Paris 6, Muséum National d'Histoire Naturelle, CP 38, 57 Rue Cuvier, 75231 Paris cedex 05, France
| | - Alain Blieck
- Université de Lille-Sciences et technologies, UFR Sciences de la Terre, UMR 8198 'EvoEcoPaleo' du CNRS, Villeneuve d'Ascq cedex 59655, France
| | - Matt Friedman
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
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53
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Andreev P, Coates MI, Karatajūtė-Talimaa V, Shelton RM, Cooper PR, Wang NZ, Sansom IJ. The systematics of the Mongolepidida (Chondrichthyes) and the Ordovician origins of the clade. PeerJ 2016; 4:e1850. [PMID: 27350896 PMCID: PMC4918221 DOI: 10.7717/peerj.1850] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Accepted: 03/05/2016] [Indexed: 11/20/2022] Open
Abstract
The Mongolepidida is an Order of putative early chondrichthyan fish, originally erected to unite taxa from the Lower Silurian of Mongolia. The present study reassesses mongolepid systematics through the examination of the developmental, histological and morphological characteristics of scale-based specimens from the Upper Ordovician Harding Sandstone (Colorado, USA) and the Upper Llandovery–Lower Wenlock Yimugantawu (Tarim Basin, China), Xiushan (Guizhou Province, China) and Chargat (north-western Mongolia) Formations. The inclusion of the Mongolepidida within the Class Chondrichthyes is supported on the basis of a suite of scale attributes (areal odontode deposition, linear odontocomplex structure and lack of enamel, cancellous bone and hard-tissue resorption) shared with traditionally recognized chondrichthyans (euchondrichthyans, e.g., ctenacanthiforms). The mongolepid dermal skeleton exhibits a rare type of atubular dentine (lamellin) that is regarded as one of the diagnostic features of the Order within crown gnathostomes. The previously erected Mongolepididae and Shiqianolepidae families are revised, differentiated by scale-base histology and expanded to include the genera Rongolepisand Xinjiangichthys, respectively. A newly described mongolepid species (Solinalepis levis gen. et sp. nov.) from the Ordovician of North America is treated as family incertae sedis, as it possesses a type of basal bone tissue (acellular and vascular) that has yet to be documented in other mongolepids. This study extends the stratigraphic and palaeogeographic range of Mongolepidida and adds further evidence for an early diversification of the Chondrichthyes in the Ordovician Period, 50 million years prior to the first recorded appearance of euchondrichthyan teeth in the Lower Devonian.
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Affiliation(s)
- Plamen Andreev
- School of Geography, Earth and Environmental Sciences, University of Birmingham , Birmingham , United Kingdom
| | - Michael I Coates
- Department of Organismal Biology and Anatomy, University of Chicago , Chicago , United States
| | | | - Richard M Shelton
- School of Dentistry, University of Birmingham , Birmingham , United Kingdom
| | - Paul R Cooper
- School of Dentistry, University of Birmingham , Birmingham , United Kingdom
| | - Nian-Zhong Wang
- Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences , Beijing , China
| | - Ivan J Sansom
- School of Geography, Earth and Environmental Sciences, University of Birmingham , Birmingham , United Kingdom
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54
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Lu J, Giles S, Friedman M, den Blaauwen J, Zhu M. The Oldest Actinopterygian Highlights the Cryptic Early History of the Hyperdiverse Ray-Finned Fishes. Curr Biol 2016; 26:1602-1608. [DOI: 10.1016/j.cub.2016.04.045] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 03/29/2016] [Accepted: 04/18/2016] [Indexed: 10/21/2022]
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55
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Keating JN, Donoghue PCJ. Histology and affinity of anaspids, and the early evolution of the vertebrate dermal skeleton. Proc Biol Sci 2016; 283:20152917. [PMID: 26962140 PMCID: PMC4810860 DOI: 10.1098/rspb.2015.2917] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Accepted: 02/15/2016] [Indexed: 12/03/2022] Open
Abstract
The assembly of the gnathostome bodyplan constitutes a formative episode in vertebrate evolutionary history, an interval in which the mineralized skeleton and its canonical suite of cell and tissue types originated. Fossil jawless fishes, assigned to the gnathostome stem-lineage, provide an unparalleled insight into the origin and evolution of the skeleton, hindered only by uncertainty over the phylogenetic position and evolutionary significance of key clades. Chief among these are the jawless anaspids, whose skeletal composition, a rich source of phylogenetic information, is poorly characterized. Here we survey the histology of representatives spanning anaspid diversity and infer their generalized skeletal architecture. The anaspid dermal skeleton is composed of odontodes comprising spheritic dentine and enameloid, overlying a basal layer of acellular parallel fibre bone containing an extensive shallow canal network. A recoded and revised phylogenetic analysis using equal and implied weights parsimony resolves anaspids as monophyletic, nested among stem-gnathostomes. Our results suggest the anaspid dermal skeleton is a degenerate derivative of a histologically more complex ancestral vertebrate skeleton, rather than reflecting primitive simplicity. Hypotheses that anaspids are ancestral skeletonizing lampreys, or a derived lineage of jawless vertebrates with paired fins, are rejected.
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Affiliation(s)
- Joseph N Keating
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK Department of Earth Sciences, Natural History Museum, Cromwell Road, South Kensington, London SW7 5BD, UK
| | - Philip C J Donoghue
- School of Earth Sciences, University of Bristol, Life Sciences Building, Tyndall Avenue, Bristol BS8 1TQ, UK
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56
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Rasch LJ, Martin KJ, Cooper RL, Metscher BD, Underwood CJ, Fraser GJ. An ancient dental gene set governs development and continuous regeneration of teeth in sharks. Dev Biol 2016; 415:347-370. [PMID: 26845577 DOI: 10.1016/j.ydbio.2016.01.038] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 01/11/2016] [Accepted: 01/29/2016] [Indexed: 12/20/2022]
Abstract
The evolution of oral teeth is considered a major contributor to the overall success of jawed vertebrates. This is especially apparent in cartilaginous fishes including sharks and rays, which develop elaborate arrays of highly specialized teeth, organized in rows and retain the capacity for life-long regeneration. Perpetual regeneration of oral teeth has been either lost or highly reduced in many other lineages including important developmental model species, so cartilaginous fishes are uniquely suited for deep comparative analyses of tooth development and regeneration. Additionally, sharks and rays can offer crucial insights into the characters of the dentition in the ancestor of all jawed vertebrates. Despite this, tooth development and regeneration in chondrichthyans is poorly understood and remains virtually uncharacterized from a developmental genetic standpoint. Using the emerging chondrichthyan model, the catshark (Scyliorhinus spp.), we characterized the expression of genes homologous to those known to be expressed during stages of early dental competence, tooth initiation, morphogenesis, and regeneration in bony vertebrates. We have found that expression patterns of several genes from Hh, Wnt/β-catenin, Bmp and Fgf signalling pathways indicate deep conservation over ~450 million years of tooth development and regeneration. We describe how these genes participate in the initial emergence of the shark dentition and how they are redeployed during regeneration of successive tooth generations. We suggest that at the dawn of the vertebrate lineage, teeth (i) were most likely continuously regenerative structures, and (ii) utilised a core set of genes from members of key developmental signalling pathways that were instrumental in creating a dental legacy redeployed throughout vertebrate evolution. These data lay the foundation for further experimental investigations utilizing the unique regenerative capacity of chondrichthyan models to answer evolutionary, developmental, and regenerative biological questions that are impossible to explore in classical models.
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Affiliation(s)
- Liam J Rasch
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Kyle J Martin
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Rory L Cooper
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Brian D Metscher
- Department of Theoretical Biology, University of Vienna, Vienna A-1090, Austria
| | - Charlie J Underwood
- Department of Earth and Planetary Sciences, Birkbeck, University of London, London WC1E 7HX, United Kingdom
| | - Gareth J Fraser
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, United Kingdom.
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57
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Brazeau MD, de Winter V. The hyoid arch and braincase anatomy of Acanthodes support chondrichthyan affinity of 'acanthodians'. Proc Biol Sci 2015; 282:20152210. [PMID: 26674952 PMCID: PMC4707761 DOI: 10.1098/rspb.2015.2210] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 11/13/2015] [Indexed: 11/24/2022] Open
Abstract
Solving the evolutionary relationships of the acanthodians is one of the key problems in reconstructing ancestral anatomical conditions for the jawed vertebrates (gnathostomes). Current debate concerns whether acanthodians are an assemblage of stem chondrichthyans, or a more generalized grade encompassing some early stem osteichthyans. The skull anatomy of Acanthodes bronni has been pivotal in these debates, owing to tension between chondrichthyan- and osteichthyan-like models of reconstruction. We use computed tomography scanning and traditional palaeontological techniques to resolve the long-standing debate about the anatomy of the jaw suspension. We establish the correct length of the hyomandibula and show that it attaches to a process on the ventrolateral angle of the braincase below the jugular vein groove. This condition corresponds precisely to that in chondrichthyans. This character represents an unambiguously optimized synapomorphy with chondrichthyans given current gnathostome phylogenies, corroborating the growing consensus of the chondrichthyan affinity of acanthodians.
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Affiliation(s)
- Martin D Brazeau
- Naturalis Biodiversity Centre, 9517, 2300 RA, Leiden, The Netherlands
| | - Valerie de Winter
- Institute of Biology, Leiden University, PO Box 9505, 2300 RA, Leiden, The Netherlands
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58
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Hilton EJ, Schnell NK, Konstantinidis P. When Tradition Meets Technology: Systematic Morphology of Fishes in the Early 21stCentury. COPEIA 2015. [DOI: 10.1643/ci-14-178] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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59
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Sallan L, Galimberti AK. Body-size reduction in vertebrates following the end-Devonian mass extinction. Science 2015; 350:812-5. [DOI: 10.1126/science.aac7373] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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60
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Baron MG. An investigation of the genus Mesacanthus(Chordata: Acanthodii) from the Orcadian Basin and Midland Valley areas of Northern and Central Scotland using traditional morphometrics. PeerJ 2015; 3:e1331. [PMID: 26539330 PMCID: PMC4631467 DOI: 10.7717/peerj.1331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 09/25/2015] [Indexed: 11/20/2022] Open
Abstract
Mesacanthus is a common and speciose genus of acanthodian fish from Lower Old Red Sandstone and Middle Old Red Sandstone assemblages (representing the Lower Devonian and Middle Devonian respectively) and is well represented in many palaeoichthyology collections in the UK. Based upon descriptions given during the 19th century, specimens of the genus Mesacanthus from the Orcadian Basin and Midland Valley areas of Northern and Central Scotland have historically been referred to a number of different species; of these, the most frequently discussed in the literature are M. mitchelli, M. peachi and M. pusillus. In order to test the validity of these three species, traditional morphometric analyses were carried out on over 100 specimens of Mesacanthus, from both the Lower Devonian and the Middle Devonian, that cover the full range of known localities for these taxa in Northern and Central Scotland. Based upon morphological and morphometric comparisons, this investigation has found that at least two species of Mesacanthus are valid (M. mitchelli and M. pusillus) as specimens from the Lower Devonian and Middle Devonian have been shown to differ significantly in a number of important ways. However, no evidence has been found for the validity of the second and distinct Middle Devonian species, M. peachi.
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Affiliation(s)
- Matthew G. Baron
- Department of Earth Science, University of Cambridge, Cambridge, United Kingdom
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61
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Organ CL, Cooper LN, Hieronymus TL. Macroevolutionary developmental biology: Embryos, fossils, and phylogenies. Dev Dyn 2015; 244:1184-92. [PMID: 26250386 DOI: 10.1002/dvdy.24318] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 12/23/2022] Open
Abstract
The field of evolutionary developmental biology is broadly focused on identifying the genetic and developmental mechanisms underlying morphological diversity. Connecting the genotype with the phenotype means that evo-devo research often considers a wide range of evidence, from genetics and morphology to fossils. In this commentary, we provide an overview and framework for integrating fossil ontogenetic data with developmental data using phylogenetic comparative methods to test macroevolutionary hypotheses. We survey the vertebrate fossil record of preserved embryos and discuss how phylogenetic comparative methods can integrate data from developmental genetics and paleontology. Fossil embryos provide limited, yet critical, developmental data from deep time. They help constrain when developmental innovations first appeared during the history of life and also reveal the order in which related morphologies evolved. Phylogenetic comparative methods provide a powerful statistical approach that allows evo-devo researchers to infer the presence of nonpreserved developmental traits in fossil species and to detect discordant evolutionary patterns and processes across levels of biological organization.
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Affiliation(s)
- Chris L Organ
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana.,Department of Earth Sciences, Montana State University, Bozeman, Montana
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62
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Giles S, Coates MI, Garwood RJ, Brazeau MD, Atwood R, Johanson Z, Friedman M. Endoskeletal structure in Cheirolepis (Osteichthyes, Actinopterygii), An early ray-finned fish. PALAEONTOLOGY 2015; 58:849-870. [PMID: 27478252 PMCID: PMC4950109 DOI: 10.1111/pala.12182] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 05/30/2015] [Indexed: 06/06/2023]
Abstract
As the sister lineage of all other actinopterygians, the Middle to Late Devonian (Eifelian-Frasnian) Cheirolepis occupies a pivotal position in vertebrate phylogeny. Although the dermal skeleton of this taxon has been exhaustively described, very little of its endoskeleton is known, leaving questions of neurocranial and fin evolution in early ray-finned fishes unresolved. The model for early actinopterygian anatomy has instead been based largely on the Late Devonian (Frasnian) Mimipiscis, preserved in stunning detail from the Gogo Formation of Australia. Here, we present re-examinations of existing museum specimens through the use of high-resolution laboratory- and synchrotron-based computed tomography scanning, revealing new details of the neuro-cranium, hyomandibula and pectoral fin endoskeleton for the Eifelian Cheirolepis trailli. These new data highlight traits considered uncharacteristic of early actinopterygians, including an uninvested dorsal aorta and imperforate propterygium, and corroborate the early divergence of Cheirolepis within actinopterygian phylogeny. These traits represent conspicuous differences between the endoskeletal structure of Cheirolepis and Mimipiscis. Additionally, we describe new aspects of the parasphenoid, vomer and scales, most notably that the scales display peg-and-socket articulation and a distinct neck. Collectively, these new data help clarify primitive conditions within ray-finned fishes, which in turn have important implications for understanding features likely present in the last common ancestor of living osteichthyans.
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Affiliation(s)
- Sam Giles
- Department of Earth SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3ANUK
| | - Michael I. Coates
- Department of Organismal Biology and AnatomyUniversity of Chicago1027 E. 57th StreetChicagoIL60637USA
- Committee on Evolutionary BiologyUniversity of Chicago1025 E. 57th StreetChicagoIL60637USA
| | - Russell J. Garwood
- School of Earth, Atmospheric and Environmental SciencesThe University of ManchesterManchesterM13 9PLUK
- The Manchester X‐Ray Imaging FacilitySchool of MaterialsThe University of ManchesterManchesterM13 9PLUK
| | - Martin D. Brazeau
- Department of Life SciencesImperial College LondonSilwood Park CampusBuckhurst RoadAscotSL5 7PYUK
| | - Robert Atwood
- The Joint Engineering and Environmental Processing BeamlineDiamond Light SourceThe Harwell Science and Innovation CampusDidcotOX11 0DEUK
| | - Zerina Johanson
- Department of Earth SciencesNatural History MuseumCromwell RoadLondonSW7 5BDUK
| | - Matt Friedman
- Department of Earth SciencesUniversity of OxfordSouth Parks RoadOxfordOX1 3ANUK
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63
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Brazeau MD, Friedman M. The origin and early phylogenetic history of jawed vertebrates. Nature 2015; 520:490-7. [PMID: 25903631 DOI: 10.1038/nature14438] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 02/09/2015] [Indexed: 11/09/2022]
Abstract
Fossils of early gnathostomes (or jawed vertebrates) have been the focus of study for nearly two centuries. They yield key clues about the evolutionary assembly of the group's common body plan, as well the divergence of the two living gnathostome lineages: the cartilaginous and bony vertebrates. A series of remarkable new palaeontological discoveries, analytical advances and innovative reinterpretations of existing fossil archives have fundamentally altered a decades-old consensus on the relationships of extinct gnathostomes, delivering a new evolutionary framework for exploring major questions that remain unanswered, including the origin of jaws.
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Affiliation(s)
- Martin D Brazeau
- Department of Life Sciences, Imperial College London, Silwood Park Campus, Buckhurst Road, Ascot SL5 7PY, UK
| | - Matt Friedman
- Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
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64
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Miyashita T. Fishing for jaws in early vertebrate evolution: a new hypothesis of mandibular confinement. Biol Rev Camb Philos Soc 2015; 91:611-57. [DOI: 10.1111/brv.12187] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2014] [Revised: 03/18/2015] [Accepted: 03/19/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Tetsuto Miyashita
- Department of Biological Sciences; University of Alberta; Edmonton Alberta T6G 2E9 Canada
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