Project 713: J. L. Carballido, J. S. Marpmann, D. Schwarz-Wings, B. Pabst. 2012. New information on a juvenile sauropod specimen from the Morrison Formation and the reassessment of its systematic position. Palaeontology. Early View (March 12).
Specimen: † Brachiosauridae (SMA:0009)

Abstract

Morphological changes in the ontogeny of sauropods are poorly known, making difficult to establish the systematic affinities of very young individuals. New information on an almost complete juvenile sauropod (SMA 0009) with an estimated total length of about 2 m is here presented. The specimen was described as a diplodocid owing to the presence of some putative synapomorphies of this group. However, recent further preparation revealed the absence of diplodocid characters and the presence of macronarian derived characters. To test the affinities of this specimen, a phylogenetic analysis was conducted. The strict consensus tree recovers the specimen as a basal titanosauriform, in an unresolved relation with Brachiosaurus and Giraffatitan. Nevertheless, a brachiosaurid assignment is here suggested in base of the widely accepted monophyly of this group (only recovered when SMA 0009 is placed within this group). Although the existence of a new taxon cannot be completely ruled out, the combination of derived and plesiomorphic characters in the specimen suggests its assignment to Brachiosaurus. Sixteen extra steps are needed to place this specimen within Diplodocidae. The high cost to place this specimen within this group is owing to the fact that several diplodocid characters are absent in SMA 0009, such as the absence of divided centroprezygapophyseal lamina in cervical vertebrae, procoelous anterior caudal centra, composed lateral lamina in anterior caudal vertebrae, elongated middle caudal vertebrae, short cervical ribs and caudolateral projection of distal condyle of metatarsal I. Finally, the systematic position reveals few major ontogenetic transformations. These affect the pneumatic structures (e.g. change from simple pleurocoels in the cervical vertebrae to complex pleurocoels and the development of lateral excavations in the dorsal vertebrae) but also include unrecorded transformations of the neural spine (e.g. the development of the spinodiapophyseal lamina, the widening of the neural spines in the dorsal vertebrae) and allometric growth in some limb bones.


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Project DOI: 10.7934/P713, http://dx.doi.org/10.7934/P713
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 2 Documents
  • 33 Taxa
  • 1 Specimen
  • 334 Characters
Total size of project's media files: 1 MB

Download Project SDD File
Total scored cells: 6122
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 334
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 754
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:334/0
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MorphoBank Project 713


    Members

    member name taxa specimens media chars character
    media
    labels
    cell scorings
    (scored, NPA, "-")
    cell
    medialabels
    rules
    MorphoBank Curator
    Project Administrator
    Last logged in 05/07/13
    3311334006122
    (6091, 0, 31)
    000
    Maureen Admin
    Full membership
    Last logged in 05/06/13
    0000000
    (0, 0, 0)
    000
    Jose Luis Carballido
    Full membership
    Last logged in Never
    0000000
    (0, 0, 0)
    000


    Taxonomic Overview for Matrix 'M2028' (32 Taxa)

    taxon unscored
    cells
    scored
    cells
    no cell
    support
    NPA
    cells
    "-" cellscell images labels on
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    member
    access
    [1] † Prosauropoda
    Last Modified in 12/05/13
    533232702003
    [2] † Theropoda
    Last Modified in 12/05/13
    233132804003
    [3] † Vulcanodon
    Last Modified in 12/05/13
    235999900003
    [4] † Barapasaurus
    Last Modified in 12/05/13
    19813613600003
    [5] † Omeisaurus
    Last Modified in 12/05/13
    3130630300003
    [6] † Shunosaurus
    Last Modified in 12/05/13
    2431031000003
    [7] † Patagosaurus
    Last Modified in 12/05/13
    16517016900003
    [8] † Mamenchisaurus
    Last Modified in 12/05/13
    7925625401003
    [9] † Apatosaurus
    Last Modified in 12/05/13
    2231431200003
    [10] † Barosaurus
    Last Modified in 12/05/13
    21412012000003
    [11] † B altithorax
    Last Modified in 12/05/13
    250848400003
    [12] † B brancai
    Last Modified in 12/05/13
    1332232100003
    [13] † Camarasaurus
    Last Modified in 12/05/13
    133433300003
    [14] † Dicraeosaurus
    Last Modified in 12/05/13
    8226125200003
    [15] † Diplodocus
    Last Modified in 12/05/13
    1931831500003
    [16] † Haplocanthosaurus
    Last Modified in 12/05/13
    19214414200003
    [17] † Amargasaurus
    Last Modified in 12/05/13
    21312012001003
    [18] † Euhelopus
    Last Modified in 12/05/13
    15517917900003
    [19] † Jobaria
    Last Modified in 12/05/13
    10123323300003
    [20] † Malawisaurus
    Last Modified in 12/05/13
    17815615600003
    [21] † Nigersaurus
    Last Modified in 12/05/13
    258696907003
    [22] † Limaysaurus
    Last Modified in 12/05/13
    14418318208003
    [23] † Rebbachisaurus
    Last Modified in 12/05/13
    301333300003
    [24] † Alamosaurus
    Last Modified in 12/05/13
    18614514503003
    [25] † Nemegtosaurus
    Last Modified in 12/05/13
    242919101003
    [26] † Opisthocoelicaudia
    Last Modified in 12/05/13
    13319719704003
    [27] † Rapetosaurus
    Last Modified in 12/05/13
    9723723700003
    [28] † Saltasaurus
    Last Modified in 12/05/13
    15717717700003
    [29] † Isisaurus
    Last Modified in 12/05/13
    21312112100003
    [30] † Losillasaurus
    Last Modified in 12/05/13
    269656500003
    [31] † Suuwassea
    Last Modified in 12/05/13
    21312312100003
    [32] † SMA 0009
    Last Modified in 12/05/13
    21412512000003


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    Documents list1569
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    Taxon list11943




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