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Helaletidae

Mammalia - Perissodactyla - Helaletidae

Taxonomy
Helaletidae was named by Osborn (1892).

It was synonymized subjectively with Lophiodontidae by Hay (1902); it was reranked as the subfamily Helaletinae by Osborn (1923).

It was assigned to Lophiodontidae by Osborn (1923); to Perissodactyla by Hough (1955) and Dehm and Oettingen-Spielberg (1958); to Rhinocerotoidea by Radinsky (1966); to Tapiroidea by Peterson (1919), Radinsky (1963) and Holbrook (1999); and to Tapiromorpha by Bai et al. (2017).

Synonymy list
YearName and author
1892Helaletidae Osborn
1919Helaletidae Peterson p. 104
1923Helaletinae Osborn p. 2
1955Helaletidae Hough p. 29
1958Helaletidae Dehm and Oettingen-Spielberg p. 24
1963Helaletidae Radinsky p. 9
1966Helaletidae Radinsky p. 631
1999Helaletidae Holbrook p. 346
2017Helaletidae Bai 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()
—Mammaliamorpha
RankNameAuthor
—Mammaliaformes
classMammalia
—Cladotheria
—Zatheria
subclassTribosphenida()
subclassTheria
—Eutheria()
—Placentalia
—Boreoeutheria
—Laurasiatheria
—Scrotifera
—Euungulata
—Panperissodactyla
superorderPerissodactylamorpha
orderPerissodactyla()
—Tapiromorpha(Haeckel 1873)
—Ceratomorpha(Wood 1937)
superfamilyTapiroideaGill 1872
familyHelaletidaeOsborn 1892
familyHelaletidaeOsborn 1892

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. †Helaletidae Osborn 1892
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G. †Desmatotherium Scott 1883
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Invalid names: Chasmotheroides Wood 1934 [synonym]
G. †Jhagirilophus Thewissen et al. 2001
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†Jhagirilophus chorgalensis Thewissen et al. 2001
G. †Paracolodon Matthew and Granger 1925
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†Paracolodon curtus Matthew and Granger 1925
†Paracolodon fissus Matthew and Granger 1925
†Paracolodon inceptus Matthew and Granger 1925
G. †Vastanolophus Smith et al. 2015
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†Vastanolophus holbrooki Smith et al. 2015
Invalid names: Chasmotheriinae Viret 1858 [empty], Helaletinae Osborn 1892 [empty]
Diagnosis
ReferenceDiagnosis
L. B. Radinsky 1963Small to medium-sized cursorial tapiroids. Dental formula Ij*: 0}:°: 1
P4.3iMI.L0ng post-canine diastemata. P "* tend to become molariform, with hypocone 12
separating posteriorly from protocone. M " metacone flattened, shortened, and lingually 3
displaced, with labial cingulum. M relatively long and narrow, with metacone reduced and metaloph shorter than protoloph. Pa present only in early Eocene forms; P2_4 tend to become molariform but never develop a hypolophid. M^j, metalophid greatly reduced to absent. M3 hypoconulid short and narrow except in Dilophodon where it is lost. Greatly enlarged nasal incisions in middle Eocene and later forms.
Measurements
No measurements are available
Composition: phosphaticsubp
Environment: terrestrialsubc
Locomotion: actively mobilec
Life habit: ground dwellingsuperf
Diet: browsersuperf
Reproduction: viviparoussubc
Created: 2005-08-31 15:03:27
Modified: 2005-08-31 17:03:27
Source: superf = superfamily, subc = subclass, c = class, subp = subphylum
References: Colbert and Schoch 1998, Carroll 1988, Lillegraven 1979, Hendy et al. 2009, Ji et al. 2002

Age range: base of the Wasatchian to the top of the Duchesnean or 55.80000 to 37.00000 Ma

Collections (15 total)


Time interval Ma Country or state Original ID and collection number
Ypresian56.0 - 47.8India (Gujarat) Vastanolophus holbrooki (55494)
Arshantan56.0 - 37.71Kazakhstan Helaletidae indet. (31009)
Irdinmanhan56.0 - 37.71China (Nei Mongol) Desmatotherium mongoliense (109067)
Wasatchian55.8 - 50.3USA (Wyoming) Helaletidae indet. (15552 15559 15575 15577 15578)
Bridgerian50.3 - 46.2USA (Wyoming) Helaletidae indet. (16260)
Lutetian47.8 - 41.3Pakistan (Punjab) Helaletidae indet. (45529)
Middle Eocene47.8 - 37.71China (Nei Mongol) Helaletidae indet. (28786)
Middle Eocene47.8 - 37.71Pakistan (Punjab) Jhagirilophus chorgalensis (87965)
Middle Eocene47.8 - 37.71Mongolia Irdinolophus mongoliensis (174909)
Duchesnean39.7 - 37.0USA (Utah) Helaletidae indet. (16877)
Late/Upper Eocene37.2 - 33.9Mongolia Paracolodon curtus (73781)