Project 2770: A. C. Pritchard,S. J. Nesbitt. 2017. A bird-like skull in a Triassic diapsid reptile increases heterogeneity of the morphological and phylogenetic radiation of Diapsida. Royal Society Open Science. 4 (170499):1.
Specimen: † Avicranium renestoi (AMNH/FARB:30834)
View: Life reconstruction

Abstract

The Triassic Period saw the first appearance of numerous amniote lineages (e.g. Lepidosauria, Archosauria, Mammalia) that defined Mesozoic ecosystems following the end Permian Mass Extinction, as well as the first major morphological diversification of crown-group reptiles. Unfortunately, much of our understanding of this event comes from the record of large-bodied reptiles (total body length > 1 m). Here we present a new species of drepanosaurid (small-bodied, chameleon-like diapsids) from the Upper Triassic Chinle Formation of New Mexico. Using reconstructions of micro-computed tomography data, we reveal the three-dimensional skull osteology of this clade for the first time. The skull presents many archaic anatomical traits unknown in Triassic crown-group reptiles (e.g. absence of bony support for the external ear), whereas other traits (e.g. toothless rostrum, anteriorly directed orbits, inflated endocranium) resemble derived avian theropods. A phylogenetic analysis of Permo-Triassic diapsids supports the hypothesis that drepanosaurs are an archaic lineage that originated in the Permian, far removed from crown- group Reptilia. The phylogenetic position of drepanosaurids indicates the presence of archaic Permian clades among Triassic small reptile assemblages and that morphological convergence produced a remarkably bird-like skull nearly 100 Myr before one is known to have emerged in Theropoda.


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Article DOI: https://doi.org/10.1098/rsos.170499

Project DOI: 10.7934/P2770, http://dx.doi.org/10.7934/P2770
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 56 Taxa
  • 1 Specimen
  • 307 Characters
Total size of project's media files: 2 MB

Download Project SDD File
Total scored cells: 10668
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 307
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 654
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:291/16
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MorphoBank Project 2770

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    Adam Pritchard
    Project Administrator
    Last logged in 10/20/17
    56113072280010668
    (10204, 0, 464)
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    Taxonomic Overview for Matrix 'M24849' (55 Taxa)

    taxon unscored
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    [1] † Petrolacosaurus kansasensis
    Last Modified in 10/17/17
    1727227002000none
    [2] † Orovenator mayorum
    Last Modified in 10/17/17
    21686860500none
    [3] † Huehuecuetzpalli mixtecus
    Last Modified in 10/17/17
    1351701700200none
    [4] Shinisaurus crocodilurus
    Last Modified in 10/17/17
    1327327302100none
    [5] Iguana iguana
    Last Modified in 10/17/17
    1128528501100none
    [6] Uromastyx acanthinura
    Last Modified in 10/17/17
    1927227201600none
    [7] † Gephyrosaurus bridensis
    Last Modified in 10/17/17
    7721421401600none
    [8] † Diphydontosaurus avonis
    Last Modified in 10/17/17
    1541521510200none
    [9] † Planocephalosaurus robinsonae
    Last Modified in 10/17/17
    1042042010200none
    [10] † Clevosaurus brasiliensis
    Last Modified in 10/17/17
    1901171150200none
    [11] † Clevosaurus hudsoni
    Last Modified in 10/17/17
    7022722701000none
    [12] † Protorosaurus speneri
    Last Modified in 10/17/17
    6223523501000none
    [13] † Pamelaria dolichotrachela
    Last Modified in 10/17/17
    1101901900700none
    [14] † Azendohsaurus madagaskarensis
    Last Modified in 10/17/17
    1128728601000none
    [15] † Azendohsaurus laaroussi
    Last Modified in 10/17/17
    27233330200none
    [16] † Teraterpeton hrynewichorum
    Last Modified in 10/17/17
    1681361360300none
    [17] † Trilophosaurus buettneri
    Last Modified in 10/17/17
    828128001900none
    [18] † Trilophosaurus jacobsi
    Last Modified in 10/17/17
    1341671670600none
    [19] † Prolacerta broomi
    Last Modified in 10/17/17
    162872820900none
    [20] † Proterosuchus fergusi
    Last Modified in 10/17/17
    362652640700none
    [21] † Proterosuchus yuani
    Last Modified in 10/17/17
    812192190700none
    [22] † TropidostomaZone_Youngina
    Last Modified in 10/17/17
    1201861860100none
    [23] † Youngina capensis
    Last Modified in 10/17/17
    3226326301200none
    [24] † Mesosuchus browni
    Last Modified in 10/17/17
    2227727501000none
    [25] † Rhynchosaurus articeps
    Last Modified in 10/17/17
    5523523501700none
    [26] † Teyumbaita sulcognathus
    Last Modified in 10/17/17
    11317817801600none
    [27] † Macrocnemus bassanii
    Last Modified in 10/17/17
    772252240600none
    [28] † Macrocnemus fuyuanensis
    Last Modified in 10/17/17
    972052050500none
    [29] Langobardisaurus pandoflii concatenation
    Last Modified in 10/17/17
    1361681680300none
    [30] † Tanystropheus longobardicus
    Last Modified in 10/17/17
    242772740900none
    [31] † Tanytrachelos ahynis
    Last Modified in 10/17/17
    1301721720500none
    [32] † Amotosaurus rotfeldensis
    Last Modified in 10/17/17
    1401641630400none
    [33] † Erythrosuchus africanus
    Last Modified in 10/17/17
    482522520700none
    [34] † Euparkeria capensis
    Last Modified in 10/17/17
    582402400900none
    [35] † Batrachotomus kupferzellensis
    Last Modified in 10/17/17
    4324924701600none
    [36] † Coelophysis bauri
    Last Modified in 10/17/17
    5222622403100none
    [37] † Plateosaurus engelhardti
    Last Modified in 10/17/17
    3824023903000none
    [38] † Howesia browni
    Last Modified in 10/17/17
    1841191180500none
    [39] † Claudiosaurus germaini
    Last Modified in 10/17/17
    622392380700none
    [40] † Hovasaurus boulei
    Last Modified in 10/17/17
    1032011990500none
    [41] † Thadeosaurus colcanapi
    Last Modified in 10/17/17
    1531471470700none
    [42] † Acerosodontosaurus piveteaui
    Last Modified in 10/17/17
    2011011010500none
    [43] † Coelurosauravus elivensis
    Last Modified in 10/17/17
    1471521520800none
    [44] † Weigeltisaurus jaekeli
    Last Modified in 10/17/17
    1871161160400none
    [45] † Rautiania spp.
    Last Modified in 10/17/17
    22377770700none
    [46] † Dolabrosaurus aquatilis
    Last Modified in 10/17/17
    26143430300none
    [47] † CoelophysisDrepanosaur
    Last Modified in 10/17/17
    202939301200none
    [48] GR113
    Last Modified in 10/17/17
    29414130000none
    [49] † Drepanosaurus unguicaudatus
    Last Modified in 10/17/17
    20894940500none
    [50] † Hypuronector limnaios
    Last Modified in 10/17/17
    23271710400none
    [51] † Icarosaurus siefkeri
    Last Modified in 10/17/17
    1491551550300none
    [52] † Kuehneosaurus sp.
    Last Modified in 10/17/17
    932092090500none
    [53] † Megalancosaurus preonensis
    Last Modified in 10/17/17
    1641401400300none
    [54] † Vallesaurus cenensis
    Last Modified in 10/17/17
    1851151150700none
    [55] † Boreopricea funerea
    Last Modified in 10/17/17
    1121891890600none


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    Specimen list155
    Bibliography75
    Views for media list112




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    Total downloads from project53
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