Project 746: T. A. Dececchi, H. C. E. Larsson, D. W. E. Hone. 2012. Yixianosaurus longimanus (Theropoda: Dinosauria) and its bearing on the evolution of Maniraptora and ecology of the Jehol fauna. Vertebrata PalAsiatica. 50 (2):111-139.
Specimen: Yixianosaurus longimanus (IVPP/V:12638)

Abstract

We re-examine the partial skeleton of the enigmatic small feathered theropod Yixianosaurus longimanus from the Lower Yixian Formation, China. A phylogenetic analysis recovers Yixianosaurus as a basal maniraptoran, in a polytomy with Alvarezsaurus, Therizinosauria, Alvarezsauroidea excluding Alvarezsaurus, and a well-resolved clade of derived maniraptorans including Oviraptorsauria and Paraves. The blend in Yixianosaurus of primitive traits, such as a low brachial index and robust digit III, and derived traits, such as a subrectangular coracoid, suggests a more complicated mosaic of forelimb evolution within Maniraptora than previously proposed. The robust forelimb bones and massive, recurved, and pointed manual unguals suggest Yixianosaurus was predatory, although this assessment remains tentative until more complete fossils of this taxon are found. The basal maniraptoran phylogenetic position implies a larger range of forelimb morphologies at this point in coelurosaurian evolution. In many ways, the robust forelimb and hypertrophied recurved unguals are similar to those of Tanycolagreus and Coelurus, and may offer transitional morphologies between these taxa and basal therizinosaurs and oviraptorosaurs. The presence of large, veined, penneacous, contour feathers on Yixianosaurus indicates the origin of these integumentary structures may be deeper in coelurosaur phylogeny than previously reported. Finally, the robust, elongate forelimbs suggest a different ecological role than inferred for other sympatric small theropods, and lend support for niche partitioning within the small non-avian theropods of the Jehol fauna.


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Project DOI: 10.7934/P746, http://dx.doi.org/10.7934/P746
This project containsMatrices
  • 1 Media
  • 1 Matrix
  • 3 Documents
  • 77 Taxa
  • 1 Specimen
  • 348 Characters
Total size of project's media files: 1 MB

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Total scored cells: 11191
Total media associated with cells: 0
Total labels associated with cell media: 0
Characters
Total characters: 348
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 795
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:348/0
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MorphoBank Project 746


    Members

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    MorphoBank Curator
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    Last logged in 08/11/12
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    Maureen Admin
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    Alex Dececchi
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    Taxonomic Overview for Matrix 'M1742' (77 Taxa)

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    [1] Allosaurus
    Last Modified in 12/05/13
    1733133100003
    [2] Sinraptor
    Last Modified in 12/05/13
    7427427400003
    [3] Ingenia
    Last Modified in 12/05/13
    16118718700003
    [4] Citipati
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    9525325300003
    [5] Oviraptor
    Last Modified in 12/05/13
    265838300003
    [6] Oviraptor2
    Last Modified in 12/05/13
    24810010000003
    [7] Conchoraptor
    Last Modified in 12/05/13
    19115715700003
    [8] Incisivosaurus
    Last Modified in 12/05/13
    23611211200003
    [9] Microvenator
    Last Modified in 12/05/13
    22212612600003
    [10] Chirostenotes
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    20614214200003
    [11] Dromaeosaurus
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    24010810800003
    [12] Deinonychus
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    7827027000003
    [13] Velociraptor
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    1633233200003
    [14] Utahraptor
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    318303000003
    [15] Adasaurus
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    268808000003
    [16] Achillobator
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    22012812800003
    [17] Tsaagan
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    21213613600003
    [18] Saurornitholestes
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    265838300003
    [19] Sinornithosaurus
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    16418418400003
    [20] Microraptor
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    17517317300003
    [21] Rahonavis
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    [22] Mononykus
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    19815015000003
    [23] Shuvuuia
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    12322522500003
    [24] Patagonykus
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    259898900003
    [25] Alvarezsaurus
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    292565600003
    [26] Ornitholestes
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    13621221200003
    [27] Archaeopteryx
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    [28] Avimimus
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    16917917900003
    [29] Caudipteryx
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    18516316300003
    [30] Confuciusornis
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    [31] Struthiomimus
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    5928928900003
    [32] Gallimimus
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    [33] Garudimimus
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    [34] Pelecanimimus
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    273757500003
    [35] Harpymimus
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    [36] Troodon
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    18516316300003
    [37] Saurornithoides
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    23411411400003
    [38] Saurornithodes2
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    23111711700003
    [39] Byronosaurus
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    250989800003
    [40] Sinornithoides
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    18816016000003
    [41] Sinovenator
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    12222622600003
    [42] Mei long
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    12722122100003
    [43] EK troodontid
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    302464600003
    [44] Segnosaurus
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    19515315300003
    [45] Erlikosaurus
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    [46] Alxasaurus
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    23711111100003
    [47] Tyrannosaurus
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    [48] Gorgosaurus
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    [49] Shenzhousaurus
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    [50] Ornithomimus
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    [51] Archaeornithomimus
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    [52] Anserimimus
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    [53] Huaxiagnathus
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    [54] Sinosauropteryx
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    15319519500003
    [55] Compsognathus
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    [56] Buitreraptor
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    [57] Unenlagia
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    [58] Shanag
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    [59] Mahakala
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    [60] Falcarius
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    8726126100003
    [61] Beipiaosaurus
    Last Modified in 12/05/13
    23311511500003
    [62] Neimongosaurus
    Last Modified in 12/05/13
    22112712700003
    [63] Erliansaurus
    Last Modified in 12/05/13
    275737300003
    [64] Suzhousaurus
    Last Modified in 12/05/13
    24710110100003
    [65] Nothronychus
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    [66] Nothronychus2
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    249999900003
    [67] Enigmosaurus
    Last Modified in 12/05/13
    306424200003
    [68] Nanshiungosaurus
    Last Modified in 12/05/13
    301474700003
    [69] ?Nanshiungosaurus?
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    3399900003
    [70] Therizinosaurus
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    292565600003
    [71] Hagryphus
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    [72] Dilong
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    [73] Coelurus
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    23711111100003
    [74] Protarchaeopteryx
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    [75] Yanornis
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    [76] Jeholornis
    Last Modified in 12/05/13
    262868600003
    [77] Yixianosaurus longimanus
    Last Modified in 12/05/13
    305434300003


    Project views

    type number of views Individual items viewed (where applicable)
    Total project views24976
    Project overview2667
    Media views3981Media search (3476 views); M109374 (505 views);
    Matrix views1843Matrix landing page (1636 views); Yixianosaurus matrix (207 views);
    Specimen list1879
    Taxon list12387
    Bibliography773
    Documents list1446




    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project195
    Matrix downloads9Yixianosaurus matrix (9 downloads);
    Media downloads6M109374 (6 downloads);
    Project downloads178
    Document downloads2Dececchi et al. 2012 Yixianosaurus matrix (1 download); Yixio matrix (1 download);