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Torosaurus utahensis

Reptilia - Ceratopsidae

Taxonomy
Arrhinoceratops utahensis was named by Gilmore (1946). Its type specimen is USNM 15583. Its type locality is west side, North Horn Mountain, which is in a Maastrichtian terrestrial horizon in the North Horn Formation of Utah.

It was synonymized subjectively with Arrhinoceratops brachyops by Kuhn (1964); it was synonymized subjectively with Torosaurus latus by Dodson and Currie (1990), Lehman (1990), Hunt and Lucas (1992) and Dodson et al. (2004); it was recombined as Triceratops utahensis by Longrich (2014); it was recombined as Torosaurus utahensis by Lawson (1976), Lehman (1981), Tyson (1981), Tokaryk (1986), Lehman (1987), Derstler (1994), Lehman (1996), Sullivan et al. (2005), Wu et al. (2007), Hunt and Lehman (2008), Farke (2011), Longrich and Field (2012), Currie and Koppelhus (2014), Tweet and Santucci (2018), Lehman et al. (2018) and Mallon et al. (2022).

Synonymy list
YearName and author
1946Arrhinoceratops utahensis Gilmore pp. 42-47 fig. 12
1976Torosaurus utahensis Lawson p. 162
1981Torosaurus utahensis Lehman p. 198
1981Torosaurus utahensis Tyson p. 1247
1986Torosaurus utahensis Tokaryk p. 195
1987Torosaurus utahensis Lehman p. 206
1994Torosaurus utahensis Derstler p. 133
1996Torosaurus utahensis Lehman p. 501–502
2005Torosaurus utahensis Sullivan et al. p. 400
2007Torosaurus utahensis Wu et al. p. 1260
2008Torosaurus utahensis Hunt and Lehman pp. 1128-1129
2011Torosaurus utahensis Farke p. 6
2012Torosaurus utahensis Longrich and Field p. 5
2014Torosaurus utahensis Currie and Koppelhus p. 1035
2014Triceratops utahensis Longrich p. 303 fig. 8
2018Torosaurus utahensis Lehman et al. p. 2216
2018Torosaurus utahensis Tweet and Santucci p. 717
2022Torosaurus utahensis Mallon et al. p. 158

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RankNameAuthor
kingdomAnimalia()
Bilateria
EubilateriaAx 1987
Life
Deuterostomia
phylumChordataHaeckel 1874
subphylumVertebrata
superclassGnathostomata
Osteichthyes()
subclassSarcopterygii()
subclassDipnotetrapodomorpha(Nelson 2006)
subclassTetrapodomorpha()
Tetrapoda
Reptiliomorpha
Anthracosauria
subclassAmphibiosauriaKuhn 1967
Cotylosauria()
Amniota
Sauropsida
classReptilia
subclassEureptilia()
Romeriida
Diapsida()
RankNameAuthor
Archosauromorpha(Huene 1946)
Crocopoda
ArchosauriformesGauthier 1986
Eucrocopoda
Archosauria()
informalAvemetatarsalia
Ornithodira
Dinosauromorpha
Dinosauriformes
Dinosauria()
Ornithischia()
Genasauria
Cerapoda
Marginocephalia
Ceratopsia()
infraorderNeoceratopsia
Coronosauria
superfamilyCeratopsoidea
familyCeratopsidae
subfamilyChasmosaurinae
Triceratopsini
genusTorosaurus
speciesutahensis()

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.

Torosaurus utahensis Gilmore 1946
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Diagnosis
ReferenceDiagnosis
T. M. Lehman 1996Large chasmosaurine with broad triangular squamosals having a smooth border bearing only three subtle anterior undulations with small low elliptical epoccipitals, and a thick rounded bar along the parietal suture, a broad thin sheet-like parietal with relatively small subcircular fenestrae and numerous subtle irrelgular undulations along its posteiror margin, with epoccipitals lacking or low and elliptical, supraorbital horncores arising posterior to the orbit, tapering distally and having hollow bases. The broad triangular form of the squamosal, its smooth lateral margin, and the thin sheet-like parietal distinguish T. utahensis from both Pentaceratops sternbergii and Chasmosaurus mariscalensis.
R. K. Hunt and T. M. Lehman 2008Torosaurus utahensis differs from T. latus in having a squamosal without a thickened medial bar along the parietal suture and having a parietal with an epiparietal on the midline (modified from Farke, 2007).
Body mass estimates
estimateequationreference
 7.23 tons Ceratopsidae femur circumferenceAnderson et al. 1985
 2.19 tons Ceratopsidae humerus circumferenceAnderson et al. 1985
mean: 3.98 tons
Measurements
partNmean
femur circumference1376.0
humerus circumference1274.0

Composition: hydroxyapatiteo
Entire body: yeso
Adult length: 10 to < 100o
Adult width: 1.0 to < 10o
Adult height: 1.0 to < 10o
Architecture: compact or denseo
Ontogeny: accretion, modification of partso
Grouping: gregariouso
Environment: terrestrialsubo
Locomotion: actively mobileo
Life habit: ground dwellingsubo
Diet: herbivoresubo
Reproduction: oviparouso
Dispersal: direct/internalo
Dispersal 2: mobileo
Created: 2005-09-15 11:08:09
Modified: 2005-09-15 13:08:09
Source: subo = suborder, o = order
References: Marsh 1875, Norman and Weishampel 1991

Age range: Late/Upper Maastrichtian or 70.60000 to 66.00000 Ma

Collections (3 total)


Time interval Ma Country or state Original ID and collection number
Late/Upper Maastrichtian70.6 - 66.0USA (Texas) Pentaceratops sp. (85188) Torosaurus utahensis (69211)
Late/Upper Maastrichtian70.6 - 66.0USA (Utah) Ceratopsia indet. (type locality: 45719)