Project 694: T. J. GAUDIN. 2004. Phylogenetic relationships among sloths (Mammalia, Xenarthra, Tardigrada): the craniodental evidence. Zoological Journal of the Linnean Society. 140 (2):255-305.
Specimen: CHOLOEPUS
View: cranium (left lateral view)

Abstract

This study is undertaken in order to evaluate specific hypotheses of relationship among extant and extinct sloths(Mammalia, Xenarthra, Tardigrada). Questions of particular interest include the relationship among the three traditional family groupings of extinct ground sloths and the monophyletic or diphyletic origin of the two genera of extant tree sloths. A computer-based cladistic investigation of the phylogenetic relationships among 33 sloth genera is performed based upon 286 osteological characteristics of the skull, lower jaw, dentition and hyoid arch. Characters are polarized via comparisons with the following successive outgroups, all members of the supraordinal grouping Edentata: the Vermilingua, or anteaters; the Cingulata, or armadillos and glyptodonts; the Palaeanodonta; and the Pholidota, or pangolins. The results of the analysis strongly corroborate the diphyly of living tree sloths, with the three-toed sloth Bradypus positioned as the sister-taxon to all other sloths, and the two-toed sloth Choloepus allied with extinct members of the family Megalonychidae. These results imply that the split between the two extant sloth genera is ancient, dating back perhaps as much as 40 Myr, and that the similarities between the two taxa, including their suspensory locomotor habits, present one of the most dramatic examples of convergent evolution known among mammals. The monophyly of the three traditional ground sloth families Megatheriidae, Megalonychidae and Mylodontidaeis confirmed in the present study, and the late Miocene–Pleistocene nothrotheres are shown to form a clade. It is suggested that this latter clade merits recognition as a distinct family-level grouping, the family Nothrotheriidae. The monophyly of the Megatherioidea, a clade including members of the families Megatheriidae, Megalonychidae and Nothrotheriidae, is also supported. Within Megatherioidea, the families Nothrotheriidae and Megatheriidae form a monophyletic group called the Megatheria. The relationships within the families Megatheriidae and Mylodontidae are fully and consistently resolved, although the hypothesized scheme of relationships among the late Miocene to Pleistocene members of the mylodontid subfamily Mylodontinae differ strongly from any proposedby previous authors. Within the family Megalonychidae, Choloepus is allied to a monophyletic grouping of West Indian sloths, although the relationships within this clade are not fully resolved. © 2004 The Linnean Society of London, Zoological Journal of the Linnean Society, 2004, 140, 255–305.




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Article DOI: 10.1111/j.1096-3642.2003.00100.x

Project DOI: 10.7934/P694, http://dx.doi.org/10.7934/P694
This project containsMatrices
  • 46 Media
  • 1 Matrix
  • 4 Documents
  • 46 Taxa
  • 3 Specimens
  • 286 Characters
Total size of project's media files: 115.67M

Download Project SDD File
Total scored cells: 11053
Total media associated with cells: 44
Total labels associated with cell media: 0
Characters
Total characters: 286
Total characters with associated media: 0
Total characters with media with labels: 0
Total character states: 787
Total character states with associated media: 0
Total character states with media with labels:0
Total unordered/ordered characters:40/246
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MorphoBank Project 694

    Authors' Institutions

    • University of Tennessee



    Members

    member name taxa specimens media media
    notes
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    notes  media
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    (scored, NPA, "-")
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    Steven Heritage
    Project Administrator
    463464528602860011053
    (10584, 0, 469)
    004400
    Timothy Gaudin
    Full membership
    0000000000
    (0, 0, 0)
    00000
    Simone Hoffmann
    Full membership
    0000000000
    (0, 0, 0)
    00000
    Maureen O'Leary
    Full membership
    0000000000
    (0, 0, 0)
    00000
    Alan Turner
    Full membership
    0000000000
    (0, 0, 0)
    00000


    Taxonomic Overview for Matrix 'M1653' (46 Taxa)

    taxon unscored
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    scored
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    NPA
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    "-" cellscell images labels on
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    [1] PHOLIDOTA
    Last Modified in 12/05/13
    20207193073005
    [2] † Palaeanodon
    Last Modified in 12/05/13
    17511211100005
    [3] † Metacheiromys
    Last Modified in 12/05/13
    35235233018005
    [4] † Holmesina
    Last Modified in 12/05/13
    6021921907005
    [5] † Glyptodont
    Last Modified in 12/05/13
    4723623207005
    [6] † Prozaedyus
    Last Modified in 12/05/13
    35240240011005
    [7] EUPHRACTUS
    Last Modified in 12/05/13
    327827409005
    [8] TOLYPEUTES
    Last Modified in 12/05/13
    6282268012005
    [9] † Palaeomyrmidon
    Last Modified in 12/05/13
    1628080044005
    [10] CYCLOPES
    Last Modified in 12/05/13
    12216214060005
    [11] † Protamandua
    Last Modified in 12/05/13
    1489595043005
    [12] TAMANDUA
    Last Modified in 12/05/13
    16210209061005
    [13] MYRMECOPHAGA
    Last Modified in 12/05/13
    15211209062005
    [14] † Octodontotherium
    Last Modified in 12/05/13
    8919719700005
    [15] † Octomylodon
    Last Modified in 12/05/13
    165106106015005
    [16] † Pseudoprepotherium
    Last Modified in 12/05/13
    6022622600005
    [17] † Thinobadistes
    Last Modified in 12/05/13
    7321221201005
    [18] † Lestodon
    Last Modified in 12/05/13
    4124624500005
    [19] † Pleurolestodon
    Last Modified in 12/05/13
    9019619600005
    [20] † Glossotherium
    Last Modified in 12/05/13
    3325825300005
    [21] † Paramylodon
    Last Modified in 12/05/13
    729527900005
    [22] † Nematherium
    Last Modified in 12/05/13
    3026525600005
    [23] † Catonyx
    Last Modified in 12/05/13
    1527427100005
    [24] † Scelidotherium
    Last Modified in 12/05/13
    828327800005
    [25] † Mylodon
    Last Modified in 12/05/13
    2126325906005
    [26] CHOLOEPUS
    Last Modified in 12/05/13
    2301261012205
    [27] † Acratocnus
    Last Modified in 12/05/13
    1627527000005
    [28] † Neocnus
    Last Modified in 12/05/13
    13914614601005
    [29] † Parocnus
    Last Modified in 12/05/13
    8520520100005
    [30] † Megalocnus
    Last Modified in 12/05/13
    6122722500005
    [31] † Pliomorphus
    Last Modified in 12/05/13
    11617117000005
    [32] † Pliometanastes
    Last Modified in 12/05/13
    11517317001005
    [33] † Megalonyx
    Last Modified in 12/05/13
    628127703005
    [34] BRADYPUS
    Last Modified in 12/05/13
    3295259022205
    [35] † Pronothrotherium
    Last Modified in 12/05/13
    3325425300005
    [36] † Nothropus
    Last Modified in 12/05/13
    2126526500005
    [37] † Nothrotherium
    Last Modified in 12/05/13
    61211210015005
    [38] † Nothrotheriops
    Last Modified in 12/05/13
    2271269015005
    [39] † Eucholoeops
    Last Modified in 12/05/13
    3825624800005
    [40] † Hapalops
    Last Modified in 12/05/13
    1130827500005
    [41] † Planops
    Last Modified in 12/05/13
    3725024900005
    [42] † Eremotherium
    Last Modified in 12/05/13
    1028027501005
    [43] † Megatherium
    Last Modified in 12/05/13
    2426426101005
    [44] † Schismotherium
    Last Modified in 12/05/13
    3126325500005
    [45] † Pelecyodon
    Last Modified in 12/05/13
    5523223100005
    [46] † Analcimorphus
    Last Modified in 12/05/13
    7621421000005


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    Project downloads

    type number of downloads Individual items downloaded (where applicable)
    Total downloads from project434
    Document downloads39Gaudin.2004.Phylogenetic.relationships.among.sloths.pdf (6 downloads); Gaudin.1995.The.ear.region.of.edentates.pdf (5 downloads); Gaudin.2004_data.matrix.nex (15 downloads); Gaudin.2004_paup.block_settings.and.search.nex (13 downloads);
    Project downloads318
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    Matrix downloads54Gaudin.2004_data.matrix.nex (54 downloads);