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Megalonychidae

Mammalia - Megalonychidae

Synonyms
  • Choloepina was named by Gray (1871). It is extant.

    It was synonymized subjectively with Megalonychidae by Adam (1999).
Synonymy list
YearName and author
1855Megalonychidae Gervais
1891Megalonychidae Ameghino p. 32
1894Megalonychidae Ameghino p. 147
1897Megalonychidae Ameghino p. 505
1980Megalonychidae Kurten and Anderson p. 135
1981Megalonychidae Thurmond and Jones p. 177
1988Megalonychidae Carroll
1991Megalonychidae Nowak
1995Megalonychidae Gaudin
1995Megalonychidae Muizon and McDonald p. 224
2001Megalonychidae White and MacPhee
2002Megalonychidae McDonald and Muizon p. 350
2007Megalonychidae McDonald and Naples p. 154
2007Megalonychidae Pujos et al.
2013Megalonychidae McDonald et al. p. 1228
2017Megalonychidae McDonald and Carranza-Castañeda
2019Megalonychidae Varela et al.

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RankNameAuthor
kingdomAnimalia()
—Bilateria
—EubilateriaAx 1987
—Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
—Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
—Tetrapoda
—Reptiliomorpha
—Anthracosauria
subclassAmphibiosauriaKuhn 1967
—Cotylosauria()
—Amniota
subclassSynapsida
—Therapsida()
infraorderCynodontia()
RankNameAuthor
—Mammaliamorpha
—Mammaliaformes
classMammalia
—Theriamorpha(Rowe 1993)
—Theriiformes()
—Trechnotheria
—Cladotheria
—Zatheria
subclassTribosphenida()
subclassTheria
—Eutheria()
—Placentalia
—Americatheria
—Xenarthra()
infraorderPilosaFlower 1883
—Folivora
classEufolivoraDelsuc et al. 2001
superfamilyMegatherioideaGray 1821
familyMegalonychidaeGervais 1855
familyMegalonychidaeGervais 1855

If no rank is listed, the taxon is considered an unranked clade in modern classifications. Ranks may be repeated or presented in the wrong order because authors working on different parts of the classification may disagree about how to rank taxa.

Fm. †Megalonychidae Gervais 1855
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G. †Amphihapalops Ameghino 1891
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†Amphihapalops cadens Ameghino 1891
†Amphihapalops congermanus Ameghino 1891
†Amphihapalops gallaicus Ameghino 1891
G. †Amphiocnus Kraglievich 1922
+
†Amphiocnus paranense Kraglievich 1922
G. †Analcimorphus Ameghino 1891
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†Analcimorphus giganteus Ameghino 1894
†Analcimorphus inversus Ameghino 1891
Subfm. †Choloepodinae MacPhee 2001
+
G. †Acratocnus Anthony 1916
+
†Acratocnus antillensis Matthew 1931
†Acratocnus odontrigonus Anthony 1916
†Acratocnus ye MacPhee et al. 2001
G. Choloepus Illiger 1811
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Choloepus andinus Allen 1913
Choloepus didactylus Linnaeus 1758 [Linnaeus's two toed sloth]
+
Invalid names: Choloepus braziliensis Fitzinger 1871 [synonym], Choloepus curi Link 1795 [synonym], Choloepus florenciae Allen 1913 [synonym], Choloepus guianensis Fitzinger 1871 [synonym], Choloepus napensis Lönnberg 1922 [synonym], Choloepus unau Link 1795 [synonym]
Choloepus hoffmanni Peters 1858 [Hoffmann's two-toed sloth]
Invalid names: Choloepus didactylus columbianus Gray 1871 [synonym]
G. †Neocnus Arredondo 1961
+
†Neocnus comes Miller 1929
†Neocnus dousman MacPhee et al. 2001
†Neocnus gliriformis Matthew 1931
†Neocnus major Arredondo 1961
†Neocnus toupiti MacPhee et al. 2001
G. †Paulocnus Hooijer 1962
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†Paulocnus petrifactus Hooijer 1962
Invalid names: Acratocnini Varona 1974 [empty], Choloepodini Gray 1871 [empty], Cubanocnini Varona 1974 [empty]
G. †Deseadognathus Carlini and Scillato-Yané 2004
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†Deseadognathus riggsi Carlini and Scillato-Yané 2004
G. †Diheterocnus Kraglievich 1928
G. †Eleutherodon Mercerat 1891
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†Eleutherodon heteroclitus Mercerat 1891
G. †Eucholoeops Amegino 1887
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†Eucholaeops titan Lydekker 1894
†Eucholoeops fronto Ameghino 1891
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Invalid names: Eucholoeops latifrons Mercerat 1891 [synonym]
†Eucholoeops ingens Ameghino 1887
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Invalid names: Eucholoeops curtus Ameghino 1894 [synonym], Eucholoeops externus Ameghino 1891 [synonym], Eucholoeops latirostris Ameghino 1891 [synonym]
†Eucholoeops litoralis Ameghino 1891
†Eucholoeops titans Lyddekker 1894
G. †Eugeronops Ameghino 1891
G. †Geronops Ameghino 1891
+
†Geronops circularis Ameghino 1891
G. †Hapalops Ameghino 1887
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†Hapalops adteger Amegino 1887
†Hapalops aguirrei Mercerat 1891
†Hapalops angustipalatus Ameghino 1891
†Hapalops antistis Ameghino 1897
†Hapalops atlanticus Ameghino 1891
†Hapalops australis Mercerat 1891
†Hapalops boulei Mercerat 1891
†Hapalops brachycephalus Ameghino 1894
†Hapalops brevipalatus Ameghino 1891
+
Invalid names: Stenocephalus hybridus Mercerat 1891 [synonym]
†Hapalops cilindricus Ameghino 1891
†Hapalops cognathus Mercerat 1891
†Hapalops congermanus Ameghino 1891
†Hapalops crassidens Ameghino 1891
†Hapalops crassignathus Ameghino 1891
†Hapalops crassissimus Ameghino 1894
†Hapalops crassissimus Ameghino 1894
†Hapalops curvus Ameghino 1899
†Hapalops depressipalatus Ameghino 1891
†Hapalops diverssidens Ameghino 1891
†Hapalops elongatus Ameghino 1891
†Hapalops forticulus Ameghino 1891
†Hapalops gracilidens Ameghino 1891
†Hapalops grandaevus Moreno and Mercerat 1891
†Hapalops grandis Ameghino 1894
†Hapalops hyperleptus Ameghino 1891
†Hapalops indifferens Ameghino 1887
+
Invalid names: Stenocephalus australis Mercerat 1891 [synonym]
†Hapalops infernalis Ameghino 1887
†Hapalops latus Ameghino 1894
†Hapalops longiceps Scott 1903
†Hapalops longipalatus Ameghino 1891
†Hapalops minutus Ameghino 1891
†Hapalops platycephalus Scott 1903
†Hapalops ponderosus Scott 1903
†Hapalops primus Ameghino 1894
†Hapalops rectagulidens Ameghino 1891
†Hapalops robustus Ameghino 1891
†Hapalops rostratus Ameghino 1887
+
Invalid names: Xyophorus simus Ameghino 1887 [synonym]
†Hapalops rutimeyeri Ameghino 1891
†Hapalops sectus Ameghino 1891
†Hapalops subcuadratus Ameghino 1891
†Hapalops testudinatus Ameghino 1891
†Hapalops vulpiceps Scott 1903
Invalid names: Stenocephalus Mercerat 1891 [synonym]
G. †Holomegalonyx Scillato-Yané 1979
G. †Hyperleptus Ameghino 1891
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†Hyperleptus garzonianus Ameghino 1891
†Hyperleptus schissognathus Ameghino 1891
†Hyperleptus sectus Ameghino 1891
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Invalid names: Tapinotherium aguirrei Mercerat 1891 [synonym]
Invalid names: Tapinotherium Mercerat 1891 [synonym]
G. †Mecorhinus Ameghino 1894
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†Mecorhinus primus Ameghino 1894
Subfm. †Megalocninae
+
G. †Imagocnus MacPhee and Iturralde-Vinent 1994
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†Imagocnus zazae MacPhee and Iturralde-Vincent 1994
G. †Megalocnus Leidy 1868
+
†Megalocnus rodens Matthew and Paula Couto 1959
†Megalocnus zile MacPhee et al. 2000
G. †Parocnus Miller 1929
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†Parocnus browni Matthew 1931
†Parocnus serus Miller 1929
Invalid names: Megalocnini Kraglievich 1923 [empty], Mesocnini Varona 1974 [empty]
Subfm. †Megalonychinae Trouessart 1904
+
G. †Ahytherium Cartelle et al. 2008
+
†Ahytherium aureum Cartelle et al. 2008
Invalid names: Iporangabradyx Dos Santos 1991 [nomen nudum], Iporangabradyx collecti Dos Santos 1991 [nomen nudum]
G. †Australonyx De Iuliis et al. 2009
+
†Australonyx aquae De Iuliis et al. 2009
G. †Ereptodon Leidy 1853
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†Ereptodon priscus Leidy 1853
G. †Megalonyx Harlan 1825
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†Megalonyx curvidens Matthew 1924
†Megalonyx cuvieri Lund 1839
†Megalonyx dissimilis Leidy 1855
†Megalonyx gigas Marsh 1874
†Megalonyx jeffersonii Desmarest 1822 [Jefferson's ground sloth]
+
Invalid names: Megalonyx brachycephalus Sellards 1941 [synonym], Megalonyx californicus Stock 1913 [synonym], Megalonyx hogani Stovall 1940 [synonym], Megalonyx laqueatus Harlan 1831 [synonym], Megalonyx milleri Lyon 1938 [synonym]
†Megalonyx leidyi Lindahl 1892
†Megalonyx leptostomus Cope 1893
+
Invalid names: Megalonyx rohrmani Gustafson 1978 [synonym]
†Megalonyx loxodon Cope 1871
†Megalonyx mathisi Hirschfeld and Webb 1968
†Megalonyx obtusidens Webb and Perrigo 1985
†Megalonyx scalper Cope 1899
†Megalonyx sierrensis Sinclair 1905 [sloth]
†Megalonyx tortulus Cope 1871
†Megalonyx validus Leidy 1868
†Megalonyx wheatleyi Cope 1871
+
Invalid names: Megalonyx sphenodon Cope 1871 [synonym]
Invalid names: Megalonyx gracilis Lund 1893 [nomen nudum]
G. †Megistonyx McDonald et al. 2013
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†Megistonyx oreobios McDonald et al. 2013
G. †Pliometanastes Hirschfeld and Webb 1968
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†Pliometanastes protistus Hirschfeld and Webb 1968
+
Invalid names: Pliometanastes galushai Hirschfeld and Webb 1968 [synonym]
G. †Sinclairia Ameghino 1912
+
†Sinclairia oregoniana Ameghino 1912
G. †Megalonychops Kraglievich 1927
+
†Megalonychops primigenius Kraglievich 1926
G. †Megalonychotherium Scott 1904
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G. †Meizonyx Webb and Perrigo 1985
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†Meizonyx salvadorensis Webb and Perrigo 1985
G. †Mesocnus Matthew 1931
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†Mesocnus torrei Matthew 1931
G. †Mesopotamocnus Brandoni 2014
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Subfm. †Metopotherinae Ameghino 1902
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G. †Hapaloides Ameghino 1902
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†Hapaloides ignavus Ameghino 1902
†Hapaloides laeviusculus Ameghino 1902
†Hapaloides ponderosus Ameghino 1902
G. †Proschismotherium Ameghino 1902
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†Proschismotherium oppositum Ameghino 1902
Subfm. †Metopotherini Ameghino 1894
+
G. †Adiastemus Ameghino 1894
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†Adiastemus compressidens Ameghino 1894
G. †Metopotherium Ameghino 1891
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†Metopotherium splendens Ameghino 1891
G. †Uranokyrtus Ameghino 1894
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†Uranokyrtus bombifrons Ameghino 1894
G. †Microcnus Matthew 1931
G. †Miocnus Matthew 1931
G. †Nohochichak McDonald et al. 2017
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†Nohochichak xibalbahkah McDonald et al. 2017
G. †Nothropus Burmeister 1882
+
†Nothropus carcaranensis Bordas 1942
†Nothropus nordenskioldi Pujos et al. 2007
†Nothropus priscus Burmeister 1882
Subfm. †Ocnopodinae Hoffstetter 1954
+
G. †Ocnopus Reinhardt 1875
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†Ocnopus gracilis Lund 1840
Subfm. †Ortotheriinae Ameghino 1889
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G. †Menilaus Ameghino 1891
G. †Ortotherium Ameghino 1885
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†Ortotherium berroi Kraglievich 1932
†Ortotherium laticurvatum Ameghino 1885
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Invalid names: Amphiocnus seneum Ameghino 1891 [synonym], Amphiocnus seneus Ameghino 1891 [synonym], Menilaus affinis Ameghino 1891 [synonym], Ortotherium schlosseri Ameghino 1891 [synonym], Ortotherium scrofum Bordas 1941 [synonym]
†Ortotherium robustum Ameghino 1881
G. †Paranabradys Scillato-Yané 1980
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†Paranabradys vucetichae Scillato-Yané 1980
G. †Paraplanops Ameghino 1891
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†Paraplanops oblongus Ameghino 1891
G. †Pattersonocnus Rincón et al. 2019
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†Pattersonocnus diazgameroi Rincón et al. 2019
G. †Pliomorphus Ameghino 1885
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†Pliomorphus mutilatus Ameghino 1885
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Invalid names: Pliomorphus ameghinoi Kraglievich 1923 [synonym], Pliomorphus brevis Kraglievich 1923 [synonym]
†Pliomorphus robustus Ameghino 1885
G. †Protomegalonyx Kraglievich 1925
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†Protomegalonyx chasicoensis Scillato-Yané 1977
†Protomegalonyx doellojuradoi Kraglievich 1925
†Protomegalonyx praecursor Kraglievich 1925
G. †Pseudhapalops Ameghino 1891
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†Pseudhapalops altiramis Ameghino 1894
†Pseudhapalops forticulus Ameghino 1891
†Pseudhapalops grandis Ameghino 1894
†Pseudhapalops infernalis Ameghino 1887
†Pseudhapalops observationis Ameghino 1891
G. †Pseudortotherium Scillato-Yane 1981
G. †Torcellia Kraglievich 1923
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†Torcellia paranense Kraglievich 1923
G. †Trematherium Ameghino 1887
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†Trematherium nanum Ameghino 1891
G. †Urumacocnus Rincón et al. 2019
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†Urumacocnus urbanii Rincón et al. 2019
G. †Xibalbaonyx Stinnesbeck et al. 2017
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†Xibalbaonyx exinferis Stinnesbeck et al. 2020
†Xibalbaonyx microcaninus Stinnesbeck et al. 2018
†Xibalbaonyx oviceps Stinnesbeck et al. 2017
G. †Zacatzontli McDonald and Carranza-Castañeda 2017
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†Zacatzontli cotobrusensis Valerio et al. 2022
†Zacatzontli tecolotlanensis McDonald and Carranza-Castañeda 2017
Invalid names: Choloepidae Gray 1871 [synonym]
Diagnosis
No diagnoses are available
Measurements
partNmeanmedian
DIstal Fibula height128.5-
Humerus height280.080.0
Humerus diameter2170.0170.0

Composition: phosphaticsubp
Maximum body mass: 80 kgg
Minimum body mass: 40 kgg
Environment: terrestrialsubc
Locomotion: actively mobilec
Life habit: ground dwellingf
Diet: herbivoref
Reproduction: viviparoussubc
Comments: life habit and diet based on Nowak 1999f
Created: 2005-06-08 10:11:09
Modified: 2005-08-22 18:30:05
Source: g = genus, f = family, subc = subclass, c = class, subp = subphylum
References: Nowak 1991, Vizcaíno et al. 2010, Hendy et al. 2009, Lillegraven 1979, Carroll 1988, Ji et al. 2002

Age range

Maximum range based only on fossils: base of the Bartonian to the top of the Holocene or 41.30000 to 0.00000 Ma
Minimum age of oldest fossil (stem group age): 33.9 Ma

Collections (328 total)

Oldest occurrences

Time interval Ma Country or state Original ID and collection number
Bartonian - Priabonian41.3 - 33.9Antarctica Megalonychidae indet. (31173)
Deseadan29.0 - 21.0Bolivia (La Paz) Megalonychidae indet. (133611)
Deseadan29.0 - 21.0Argentina (Mendoza) Megalonychidae indet. (176466)
Deseadan29.0 - 21.0Bolivia Megalonychidae indet. (95688)
Deseadan29.0 - 21.0Argentina (Santa Cruz) Deseadognathus riggsi (220634)
Early/Lower Miocene23.03 - 15.97Cuba (Sancti Spiritus) Imagocnus zazae (31183)
Miocene23.03 - 5.333USA (California) Megalonychidae indet. (19376)
Colhuehuapian21.0 - 17.5Argentina (Chubut) Megalonychidae indet., Hapaloides sp., Proschismotherium sp., Holomegalonyx sp. (141368)
Burdigalian20.44 - 15.97Chile (Magallanes) Megalonychidae indet. (204203)
Burdigalian20.44 - 15.97Argentina (Santa Cruz) Hapalops sp. (59319)
Burdigalian20.44 - 15.97Chile (Aisén) Hapalops sp. (71843)
Burdigalian - Langhian20.44 - 13.82Colombia (Guajira) Hyperleptus sp. (145271)
Santacrucian17.5 - 16.3Argentina (San Juan) Hapalops sp. (197899)
Santacrucian17.5 - 16.3Argentina (Santa Cruz) Eucholoeops fronto (176563) Eucholoeops ingens (27313 176587 176643 207742) Eucholoeops sp. (176601) Eucholoeops sp., Hapalops sp. 1, Hapalops sp. 2, Hapalops sp., Eucholoeops ingens, Eucholaeops sp. 1 (142529) Eucholoeops sp., Hapalops sp., Eucholoeops fronto (176603) Eucholoeops sp., Hapalops sp., Pseudhapalops rutimeyeri (206241) Hapalops elongatus (176635 176641 207605 210638 210787) Hapalops indifferens, Hapalops elongatus, Hapalops angustipalatus, Eucholoeops fronto, Hapalops ponderosus (176585) Hapalops longiceps (176583) Hapalops platycephalus (176598) Hapalops sp. (176570 176571 176576 176592 176622 176623 176625 204358 210154) Hapalops sp. 1, Hapalops sp. 2 (176584) Hapalops sp. 1, Hapalops sp. 2, Eucholoeops fronto (176581) Hapalops sp., Hapalops gracilidens, Hapalops platycephalus (210153) Hapalops sp., Hapalops indifferens, Hapalops gracilidens, Pseudhapalops rutimeyeri, Megalonychotherium atavus (206237) Hapalops sp., Hapalops longiceps (176599) Hyperleptus sp. (176636) Hyperleptus sp., Hapalops sp. 1, Hapalops sp. 2, Eucholoeops ingens, Eucholoeops fronto, Eucholaeops sp. 1, Eucholaeops sp. 2 (142533) Hyperleptus sp., Hapalops sp., Eucholoeops ingens (176602) Megalonychidae indet., Hapalops sp. (87314) Megalonychidae indet., Hapalops sp., Hapalops elongatus (176590)
Santacrucian17.5 - 16.3Argentina (Buenos Aires) Eucholoeops ingens (207743)
Laventan13.8 - 11.0Colombia Hapalops sp. (13684 153817)
Laventan13.8 - 11.0Colombia (Huila) Eucholoeops fronto (188252) Hapalops sp. (186628 186667 187122 187888 187961 187965 187974 187975) Hapalops sp., Megalonychinae indet. (187721) Megalonychidae indet. (13650 133441 186607 186621 186683 186860 187967 187972) Megalonychidae indet., Hapalops sp. (186630 187945) Megalonychinae indet. (133689 187078 187739)
Laventan13.8 - 11.0Bolivia (Tarija) Pelecyodon sp. (38071)
Laventan13.8 - 11.0Peru (Ucayali) Megalonychidae indet. (144793)
Laventan13.8 - 11.0Colombia (Tolima) Megalonychidae indet. (132559 132580 140179 140183)