Project 825: T. Sigurdsen, A. K. Huttenlocker, S. P. Modesto, T. B. Rowe, R. Damiani. 2012. Reassessment of the morphology and paleobiology of the therocephalian Tetracynodon darti (Therapsida) and the phylogenetic relationships of Baurioidea. Journal of Vertebrate Paleontology. 32 (5):1113-1114.
Specimen: † Tetracynodon darti (UCMP:42869)

Abstract

Several new specimens of the Triassic therocephalian Tetracynodon darti have become available in recent years, allowing substantial corrections and expansions to previous descriptions. We here analyze T. darti in the context of therocephalian relationships and biology, using computed tomographic (CT) scanning to reveal details of the skull. Histological sections, as well as the degree of ossification of individual elements, both suggest that the available specimens are subadults (rather than rapidly growing neonates), and probably yearlings. A maxillary shelf bearing a long suture with the vomer similar to that of Lycideops is present, and T. darti also shares a nasal-lacrimal contact with that taxon. There is no evidence for the presence of maxilloturbinal bones. The postcranial skeleton is slender and similar to that of regisaurids and other small baurioids. The skull bones show clear indentations demarcating the major divisions of the brain, allowing one of the most detailed reconstructions of a non-mammalian therapsid brain published to date. The brain is strikingly plesiomorphic in many features, particularly in the retention of large dorsally positioned optic lobes of the tectum, but generally shows features that are intermediate between gorgonopsians and cynodonts, thus clarifying this stage of the evolution of the synapsid brain. A cladistic analysis of 33 therapsid taxa and 131 morphological characters supports the monophyly of Therocephalia, and there is evidence for a monophyletic Lycideopidae within Baurioidea. Lycideopidae contains species with long snouts, nasal-lacrimal contacts, and incipient secondary palates, including Lycideops, Choerosaurus, T. tenuis, and T. darti.


Read the article »

Project DOI: 10.7934/P825, http://dx.doi.org/10.7934/P825
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 1 Document
  • 33 Taxa
  • 1 Specimen
  • 131 Characters


Download Project SDD File
Total scored cells: 3410
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 131
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 300
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:131/0
Currently Viewing:
MorphoBank Project 825

    This research
    supported by



    Members

    member name taxa specimens media chars character
    media
    labels
    cell scorings
    (scored, NPA, "-")
    cell
    medialabels
    rules
    MorphoBank Curator
    Project Administrator
    Last logged in 08/06/14
    3311131003410
    (3394, 0, 16)
    000
    Maureen Admin
    Full membership
    Last logged in 11/21/12
    0000000
    (0, 0, 0)
    000
    Adam Huttenlocker
    Full membership
    Last logged in 11/08/12
    0000000
    (0, 0, 0)
    000
    Trond Sigurdsen
    Full membership
    Last logged in 11/09/12
    0000000
    (0, 0, 0)
    000


    Taxonomic Overview for Matrix 'M1887' (33 Taxa)

    taxon unscored
    cells
    scored
    cells
    no cell
    support
    NPA
    cells
    "-" cellscell images labels on
    cell images
    member
    access
    [1] † Biarmosuchus tener
    Last Modified in 12/05/13
    1311711701004
    [2] † Titanophoneus potens
    Last Modified in 12/05/13
    1012012001004
    [3] † Gorgonopsia
    Last Modified in 12/05/13
    712612301004
    [4] † Anomodontia
    Last Modified in 12/05/13
    1711511301004
    [5] † Charassognathus gracilis
    Last Modified in 12/05/13
    55767600004
    [6] † Dvinia prima
    Last Modified in 12/05/13
    2210910900004
    [7] † Procynosuchus delaharpeae
    Last Modified in 12/05/13
    512612600004
    [8] † Lycosuchus vanderrieti
    Last Modified in 12/05/13
    2410610601004
    [9] † Glanosuchus macrops
    Last Modified in 12/05/13
    612512401004
    [10] † Ictidosaurus angusticeps
    Last Modified in 12/05/13
    69616101004
    [11] † Pristerognathus polyodon
    Last Modified in 12/05/13
    1411611601004
    [12] † Euchambersia mirabilis
    Last Modified in 12/05/13
    49818101004
    [13] † Promoschorhynchus platyrhinus
    Last Modified in 12/05/13
    1511911501004
    [14] † Olivierosuchus parringtoni
    Last Modified in 12/05/13
    1012012001004
    [15] † Cerdops burgheri
    Last Modified in 12/05/13
    311009901004
    [16] † Moschorhinus kitchingi
    Last Modified in 12/05/13
    2011111001004
    [17] † Ictidostoma hemburyi
    Last Modified in 12/05/13
    50808001004
    [18] † Hofmeyria atavus
    Last Modified in 12/05/13
    2011211001004
    [19] † Mirotenthes digitipes
    Last Modified in 12/05/13
    1012012001004
    [20] † Viatkosuchus sumini
    Last Modified in 12/05/13
    3010110100004
    [21] † Moschowhaitsia vjuschkovi
    Last Modified in 12/05/13
    77545400004
    [22] † Theriognathus microps
    Last Modified in 12/05/13
    313312800004
    [23] † Ictidosuchus primaevus
    Last Modified in 12/05/13
    45868600004
    [24] † Ictidosuchoides longiceps
    Last Modified in 12/05/13
    1711511400004
    [25] † Ictidosuchops rubidgei
    Last Modified in 12/05/13
    69636200004
    [26] † Regisaurus jacobi
    Last Modified in 12/05/13
    1211911900004
    [27] † Choerosaurus dejageri
    Last Modified in 12/05/13
    53797800004
    [28] † Lycideops longiceps
    Last Modified in 12/05/13
    42918900004
    [29] Tetracynodon tenuis
    Last Modified in 12/05/13
    43888800004
    [30] † Tetracynodon darti
    Last Modified in 12/05/13
    1411811700004
    [31] † Scaloposaurus constrictus
    Last Modified in 12/05/13
    3110010000004
    [32] † Ericiolacerta parva
    Last Modified in 12/05/13
    43888800004
    [33] † Bauriidae
    Last Modified in 12/05/13
    1411911700004


    Project views

    type number of views Individual items viewed (where applicable)
    Total project views25266
    Project overview3275
    Media views3966Media search (3460 views); M150985 (506 views);
    Taxon list11557
    Matrix views1965Matrix landing page (1749 views); Sigurdsen et al matrix (216 views);
    Specimen list2185
    Documents list1550
    Bibliography768




    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project197
    Project downloads167
    Media downloads2M150985 (2 downloads);
    Document downloads4Copryright Clearance (4 downloads);
    Matrix downloads24Sigurdsen et al matrix (24 downloads);