Project 3931: B. C. Moon. 2019. A new phylogeny of ichthyosaurs (Reptilia: Diapsida). Journal of Systematic Palaeontology. 17 (2):129-155.
Specimen: † Ichthyosaurus breviceps (unvouchered)
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Abstract

The largest phylogenetic analysis of ichthyosaurs to date is presented, with 114 ingroup taxa coded at species level. Completeness of the taxa included varied from > 98% to < 2%; 10 taxa were removed a priori using Concatabominations due to incompleteness and taxonomic uncertainty. The data were analysed using three widely used optimization criteria, maximum parsimony, maximum likelihood and Bayesian inference; while similar, each criterion produced different topologies, support and levels of resolution. Maximum parsimony found a poorly-resolved consensus tree with moderate improvement from a posteriori pruning of unstable taxa; however, general support remained low. Tree resolution was reduced more by taxa that lacked codings from phylogenetically important regions of the tree, rather than by those that simply lacked many codings. Resolution present in the most likely tree is poorly supported; sister relationships cannot be confirmed, although similarities are found to the most parsimonious tree. Bayesian inference found poorly resolved consensus trees. While more resolved, an equal-distribution rate prior is significantly worse than the null gamma-distribution rate prior for morphological data, but suggests rate heterogeneity across ichthyosaur phylogeny. Tree comparisons under each analytical criterion failed to select a single best tree; however, the Bayesian inference tree with gamma-distribution rate prior is selected as the best tree based on recent analyses showing improved accuracy using this criterion. Unequivocally resolved clades include Ichthyopterygia, Ichthyosauria, Shastasauria, Euichthyosauria, Parvipelvia and Neoichthyosauria, but with variation in their taxonomic components. Mixosauridae and Ophthalmosauridae are similarly recovered, but their definitions are modified to stem-based definitions to prevent substantial variation of included taxa. Several genera are not monophyletic: Brachypterygius, Leptonectes, Mixosaurus, Ophthalmosaurus, Paraophthalmosaurus, Phalarodon, Platypterygius, Stenopterygius, Temnodontosaurus and Undorosaurus. Complex and variable relationships suggest the need for new characters and a re-evaluation of the state of ichthyosaur phylogenetics.


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Article DOI: 10.1080/14772019.2017.1394922

Project DOI: 10.7934/P3931, http://dx.doi.org/10.7934/P3931
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 115 Taxa
  • 1 Specimen
  • 287 Characters
Total size of project's media files: 975.22k

Download Project SDD File
Total scored cells: 16532
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 287
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 619
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:283/4
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MorphoBank Project 3931

    Authors' Institutions

    • University of Bristol



    Members

    member name taxa specimens media chars character
    media
    labels
    cell scorings
    (scored, NPA, "-")
    cell
    medialabels
    rules
    MorphoBank Curator
    Project Administrator
    115112870016532
    (15779, 0, 753)
    000
    Benjamin Moon
    Full membership
    0000000
    (0, 0, 0)
    000


    Taxonomic Overview for Matrix 'M27235' (115 Taxa)

    taxon unscored
    cells
    scored
    cells
    no cell
    support
    NPA
    cells
    "-" cellscell images labels on
    cell images
    member
    access
    [1] † Acamptonectes densus
    Last Modified in 02/17/21
    16312012004002
    [2] † Aegirosaurus leptospondylus
    Last Modified in 02/17/21
    92185185010002
    [3] † Arthropterygius chrisorum
    Last Modified in 02/17/21
    222656500002
    [4] † Athabascasaurus bitumineus
    Last Modified in 02/17/21
    186959506002
    [5] † Barracudasauroides panxianensis
    Last Modified in 02/17/21
    8619619605002
    [6] † Besanosaurus leptorhynchus
    Last Modified in 02/17/21
    10018118106002
    [7] † Brachypterygius extremus
    Last Modified in 02/17/21
    12016016007002
    [8] † Brachypterygius pseudoscythica
    Last Modified in 02/17/21
    201808006002
    [9] † Californosaurus perrini
    Last Modified in 02/17/21
    18410210201002
    [10] † Callawayia neoscapularis
    Last Modified in 02/17/21
    6022222205002
    [11] † Cartorhynchus lenticarpus
    Last Modified in 02/17/21
    122145145020002
    [12] † Caypullisaurus bonapartei
    Last Modified in 02/17/21
    10916916909002
    [13] † Chacaicosaurus cayi
    Last Modified in 02/17/21
    225555507002
    [14] † Chaohusaurus chaoxianensis
    Last Modified in 02/17/21
    6721321307002
    [15] † Chaohusaurus geishanensis
    Last Modified in 02/17/21
    17610610605002
    [16] † Chaohusaurus zhangjiawanensis
    Last Modified in 02/17/21
    114162162011002
    [17] † Contectopalatus atavus
    Last Modified in 02/17/21
    58218218011002
    [18] † Cryopterygius kielanae
    Last Modified in 02/17/21
    205777705002
    [19] † Cryopterygius kristiansenae
    Last Modified in 02/17/21
    11217117104002
    [20] † Cymbospondylus buchseri
    Last Modified in 02/17/21
    16411911904002
    [21] † Cymbospondylus nichollsi
    Last Modified in 02/17/21
    17410810805002
    [22] † Cymbospondylus petrinus
    Last Modified in 02/17/21
    4922922909002
    [23] † Cymbospondylus piscosus
    Last Modified in 02/17/21
    2834400002
    [24] † Dearcmhara shawcrossi
    Last Modified in 02/17/21
    273131301002
    [25] † Eurhinosaurus longirostris
    Last Modified in 02/17/21
    29244244014002
    [26] † Excalibosaurus costini
    Last Modified in 02/17/21
    8219719708002
    [27] † Gengasaurus nicosiai
    Last Modified in 02/17/21
    210757502002
    [28] † Grendelius alekseevi
    Last Modified in 02/17/21
    14713413406002
    [29] † Grendelius zhuravlevi
    Last Modified in 02/17/21
    242444401002
    [30] † Grippia longirostris
    Last Modified in 02/17/21
    5822222207002
    [31] † Guizhouichthyosaurus tangae
    Last Modified in 02/17/21
    2924924909002
    [32] † Guizhouichthyosaurus wolonggangense
    Last Modified in 02/17/21
    12315915905002
    [33] † Gulosaurus helmi
    Last Modified in 02/17/21
    12615815803002
    [34] † Hauffiopteryx typicus
    Last Modified in 02/17/21
    627227209002
    [35] † Himalayasaurus tibetensis
    Last Modified in 02/17/21
    275121200002
    [36] † Hudsonelpidia brevirostris
    Last Modified in 02/17/21
    193909004002
    [37] † Hupehsuchus nanchangensis
    Last Modified in 02/17/21
    114149149024002
    [38] † Ichthyosaurus acutirostris
    Last Modified in 02/17/21
    12515915903002
    [39] † Ichthyosaurus anningae
    Last Modified in 02/17/21
    11816416405002
    [40] † Ichthyosaurus breviceps
    Last Modified in 02/17/21
    5922122107002
    [41] † Ichthyosaurus communis
    Last Modified in 02/17/21
    028128106002
    [42] † Ichthyosaurus conybeari
    Last Modified in 02/17/21
    7121021006002
    [43] † Ichthyosaurus larkini
    Last Modified in 02/17/21
    7120820808002
    [44] † Ichthyosaurus somersetensis
    Last Modified in 02/17/21
    4723323307002
    [45] † Isfjordosaurus minor
    Last Modified in 02/17/21
    274131300002
    [46] † Janusaurus lundi
    Last Modified in 02/17/21
    128149149010002
    [47] † Keilhauia nui
    Last Modified in 02/17/21
    216686803002
    [48] † Leninia stellans
    Last Modified in 02/17/21
    206777704002
    [49] † Leptonectes moorei
    Last Modified in 02/17/21
    16411811805002
    [50] † Leptonectes solei
    Last Modified in 02/17/21
    16711911901002
    [51] † Leptonectes tenuirostris
    Last Modified in 02/17/21
    26250250011002
    [52] † Macgowania janiceps
    Last Modified in 02/17/21
    17411011003002
    [53] † Maiaspondylus lindoei
    Last Modified in 02/17/21
    199838305002
    [54] † Malawania anachronus
    Last Modified in 02/17/21
    221626204002
    [55] † Mikadocephalus gracilirostris
    Last Modified in 02/17/21
    17511010903002
    [56] † Mixosaurus cornalianus
    Last Modified in 02/17/21
    2525425408002
    [57] † Mixosaurus kuhnschneyderi
    Last Modified in 02/17/21
    12615515506002
    [58] † Mixosaurus xindianensis
    Last Modified in 02/17/21
    9119319303002
    [59] † Mollesaurus periallus
    Last Modified in 02/17/21
    187999901002
    [60] † Muiscasaurus catheti
    Last Modified in 02/17/21
    207787802002
    [61] † Nannopterygius enthekiodon
    Last Modified in 02/17/21
    195919101002
    [62] † Ophthalmosaurus icenicus
    Last Modified in 02/17/21
    0277277010002
    [63] † Ophthalmosaurus natans
    Last Modified in 02/17/21
    55221221011002
    [64] † Ophthalmosaurus yasykovi
    Last Modified in 02/17/21
    15412712706002
    [65] † Palvennia hoybergeti
    Last Modified in 02/17/21
    17110910907002
    [66] † Paraophthalmosaurus kabanovi
    Last Modified in 02/17/21
    212707005002
    [67] † Paraophthalmosaurus saveljeviensis
    Last Modified in 02/17/21
    200838304002
    [68] † Parvinatator wapitiensis
    Last Modified in 02/17/21
    18510010002002
    [69] † Pervushovisaurus bannovkensis
    Last Modified in 02/17/21
    261262600002
    [70] † Pervushovisaurus campylodon
    Last Modified in 02/17/21
    266212100002
    [71] † Pessopteryx nisseri
    Last Modified in 02/17/21
    215696903002
    [72] † Phalarodon callawayi
    Last Modified in 02/17/21
    15013213205002
    [73] † Phalarodon fraasi
    Last Modified in 02/17/21
    10917017008002
    [74] † Phalarodon major
    Last Modified in 02/17/21
    266191902002
    [75] † Phantomosaurus neubigi
    Last Modified in 02/17/21
    209767602002
    [76] † Platypterygius americanus
    Last Modified in 02/17/21
    107167167013002
    [77] † Platypterygius australis
    Last Modified in 02/17/21
    14255255018002
    [78] † Platypterygius hauthali
    Last Modified in 02/17/21
    244404003002
    [79] † Platypterygius hercynicus
    Last Modified in 02/17/21
    87188188012002
    [80] † Platypterygius platydactylus
    Last Modified in 02/17/21
    16811311306002
    [81] † Platypterygius sachicarum
    Last Modified in 02/17/21
    216676704002
    [82] † Qianichthyosaurus xingyiensis
    Last Modified in 02/17/21
    13014814809002
    [83] † Qianichthyosaurus zhoui
    Last Modified in 02/17/21
    70207207010002
    [84] † Quasianosteosaurus vikinghoegdai
    Last Modified in 02/17/21
    235505002002
    [85] † Sclerocormus parviceps
    Last Modified in 02/17/21
    151116116020002
    [86] † Shastasaurus liangae
    Last Modified in 02/17/21
    62194194031002
    [87] † Shastasaurus pacificus
    Last Modified in 02/17/21
    98169169020002
    [88] † Shastasaurus sikkaniensis
    Last Modified in 02/17/21
    1759595017002
    [89] † Shonisaurus popularis
    Last Modified in 02/17/21
    7020920908002
    [90] † Simbirskiasaurus birjukovi
    Last Modified in 02/17/21
    231535303002
    [91] † Sisteronia seeleyi
    Last Modified in 02/17/21
    237474703002
    [92] † Stenopterygius aaleniensis
    Last Modified in 02/17/21
    11216716708002
    [93] † Stenopterygius quadriscissus
    Last Modified in 02/17/21
    1626426308002
    [94] † Stenopterygius triscissus
    Last Modified in 02/17/21
    7270270010002
    [95] † Stenopterygius uniter
    Last Modified in 02/17/21
    8220020005002
    [96] † Suevoleviathan disinteger
    Last Modified in 02/17/21
    48226226013002
    [97] † Suevoleviathan integer
    Last Modified in 02/17/21
    54223223010002
    [98] † Sveltonectes insolitus
    Last Modified in 02/17/21
    8019919908002
    [99] † Temnodontosaurus azerguensis
    Last Modified in 02/17/21
    146117117024002
    [100] † Temnodontosaurus crassimanus
    Last Modified in 02/17/21
    13614614605002
    [101] † Temnodontosaurus eurycephalus
    Last Modified in 02/17/21
    221656501002
    [102] † Temnodontosaurus nuertingensis
    Last Modified in 02/17/21
    212747401002
    [103] † Temnodontosaurus platyodon
    Last Modified in 02/17/21
    7268268012002
    [104] † Temnodontosaurus trigonodon
    Last Modified in 02/17/21
    12263263012002
    [105] † Thaisaurus chonglakmanii
    Last Modified in 02/17/21
    207757505002
    [106] † Thalattoarchon saurophagis
    Last Modified in 02/17/21
    211757501002
    [107] † Tholodus schmidi
    Last Modified in 02/17/21
    265202002002
    [108] † Toretocnemus californicus
    Last Modified in 02/17/21
    220636304002
    [109] † Toretocnemus zitteli
    Last Modified in 02/17/21
    15911911909002
    [110] † Undorosaurus gorodischensis
    Last Modified in 02/17/21
    16511711705002
    [111] † Undorosaurus trautscholdi
    Last Modified in 02/17/21
    235494903002
    [112] † Utatsusaurus hataii
    Last Modified in 02/17/21
    9119419402002
    [113] † Wahlisaurus massarae
    Last Modified in 02/17/21
    17510910903002
    [114] † Wimanius odontopalatus
    Last Modified in 02/17/21
    234515102002
    [115] † Xinminosaurus catactes
    Last Modified in 02/17/21
    18110210204002


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