Project 3756: T. R. Lyson, J. L. Sayler, W. G. Joyce. 2019. A new baenid turtle, Saxochelys gilberti, gen. et sp. nov., from the uppermost cretaceous (Maastrichtian) Hell Creek Formation: sexual dimorphism and spatial niche partitioning within the most speciose group of Late Cretaceous turtles. Journal of Vertebrate Paleontology. 39 (4):e1662428.
Specimen: † Baena hayi (USNM: V 6728_3)
View: dorsal

Abstract

The uppermost Cretaceous (Maastrichtian) Hell Creek Formation in North America has yielded a diverse assemblage of fossil turtles dominated by baenids. A population of over 30 individual skeletons from the Hell Creek Formation of North Dakota comprises a new baenid turtle, Saxochelys gilberti, increasing the number of recognized Hell Creek turtles to at least 26, 11 of which are baenids. Saxochelys gilberti is differentiated from all other baenids based on the presence of a nuchal scale, finely sculptured shell, absence of an omega-shaped femoral-anal sulcus, presence of an omega-shaped extragular-humeral sulcus, a cavum tympani that is relatively smaller than the diameter of the orbit, presence of a robust single scale on the posteromedial portion of the parietals, and jugal exclusion from the orbital margin. Two distinct plastral morphologies, concave (N = 8) and flat (N = 9), are interpreted as representing male and female individuals, respectively. A ca. 10% size difference between the sexes indicates that S. gilberti is a sexually size-dimorphic turtle with larger females. This suggests female mate choice in this baenid turtle. A referred S. gilberti skeleton from above the Cretaceous–Paleogene boundary provides evidence for the survival of yet another species of turtle across this extinction event. The type locality of S. gilberti is close both stratigraphically and geographically to another locality consisting of a completely different assortment of baenid species, suggesting a fine degree of spatial niche partitioning in baenid turtles that may help explain the extremely high diversity of the group within the Hell Creek Formation.


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Article DOI: 10.1080/02724634.2019.1662428

Project DOI: 10.7934/P3756, http://dx.doi.org/10.7934/P3756
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 34 Taxa
  • 1 Specimen
  • 69 Characters
Total size of project's media files: 2.05M

Download Project SDD File
Total scored cells: 1518
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 69
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 157
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:54/15
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MorphoBank Project 3756

    Authors' Institutions

    • Université de Fribourg (University of Fribourg)

    • Yale University

    • Denver Museum of Nature and Science



    Members

    member name taxa specimens media chars character
    media
    labels
    cell scorings
    (scored, NPA, "-")
    cell
    medialabels
    rules
    MorphoBank Curator
    Project Administrator
    Last logged in 06/18/20
    341169001518
    (1503, 0, 15)
    000
    Tyler Lyson
    Full membership
    Last logged in Never
    0000000
    (0, 0, 0)
    000


    Taxonomic Overview for Matrix 'M26695' (34 Taxa)

    taxon unscored
    cells
    scored
    cells
    no cell
    support
    NPA
    cells
    "-" cellscell images labels on
    cell images
    member
    access
    [1] † Kayentachelys aprix
    Last Modified in 06/18/20
    1666602002
    [2] † Pleurosternon bullockii
    Last Modified in 06/18/20
    9606000002
    [3] † Glyptops plicatulus
    Last Modified in 06/18/20
    5646400002
    [4] † Arundelemys dardeni
    Last Modified in 06/18/20
    38323100002
    [5] † Hayemys latifrons
    Last Modified in 06/18/20
    44252500002
    [6] † Neurankylus baueri
    Last Modified in 06/18/20
    40292900002
    [7] † Neurankylus exemius
    Last Modified in 06/18/20
    35343400002
    [8] † Neurankylus lithographicus
    Last Modified in 06/18/20
    40302900002
    [9] † Neurankylus torrejonensis
    Last Modified in 06/18/20
    26444300002
    [10] † Trinitichelys hiatti
    Last Modified in 06/18/20
    14585500002
    [11] † Scabremys ornata
    Last Modified in 06/18/20
    44262500002
    [12] † Thescelus insiliens
    Last Modified in 06/18/20
    43262600002
    [13] † Baena arenosa
    Last Modified in 06/18/20
    19494901002
    [14] † Baena affinis
    Last Modified in 06/18/20
    27414101002
    [15] † Baena escavada
    Last Modified in 06/18/20
    47242200002
    [16] † Baena hayi
    Last Modified in 06/18/20
    43252501002
    [17] † Boremys grandis
    Last Modified in 06/18/20
    45232301002
    [18] † Boremys pulchra
    Last Modified in 06/18/20
    8616001002
    [19] † Chisternon undatum
    Last Modified in 06/18/20
    6656201002
    [20] † Denazinemys nodosa
    Last Modified in 06/18/20
    8606001002
    [21] † Eubaena cephalica
    Last Modified in 06/18/20
    30393900002
    [22] † Eubaena hatcheri
    Last Modified in 06/18/20
    41282701002
    [23] † Stygiochelys estesi
    Last Modified in 06/18/20
    31383800002
    [24] † Cedrobaena brinkman
    Last Modified in 06/18/20
    11585800002
    [25] † Cedrobaena putorius
    Last Modified in 06/18/20
    38313100002
    [26] † Gammerabaena sonsalla
    Last Modified in 06/18/20
    41282800002
    [27] † Goleremys mckennai
    Last Modified in 06/18/20
    36333300002
    [28] † Palatobaena bairdi
    Last Modified in 06/18/20
    31373701002
    [29] † Palatobaena cohen
    Last Modified in 06/18/20
    5636301002
    [30] † Palatobaena gaffneyi
    Last Modified in 06/18/20
    34343401002
    [31] † Plesiobaena antiqua
    Last Modified in 06/18/20
    0696900002
    [32] † Turtle graveyard
    Last Modified in 06/18/20
    0706801002
    [33] † Saxochelys gilberti
    Last Modified in 06/18/20
    0706801002
    [34] † Arvinachelys goldeni
    Last Modified in 06/18/20
    9636000002


    Project views

    type number of views Individual items viewed (where applicable)
    Total project views895
    Project overview114
    Matrix views83Matrix landing page (63 views); Data matrix from publication (20 views);
    Media views214Media search (180 views); M692326 (34 views);
    Views for media list61
    Specimen list103
    Taxon list274
    Bibliography46




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    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project19
    Project downloads18
    Matrix downloads1Data matrix from publication (1 download);