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Torosaurus utahensis
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), 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), Mallon et al. (2022).
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), 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), Mallon et al. (2022).
Synonymy list
| Year | Name and author |
|---|---|
| 1946 | Arrhinoceratops utahensis Gilmore pp. 42-47 fig. 12 |
| 1976 | Torosaurus utahensis Lawson p. 162 |
| 1981 | Torosaurus utahensis Lehman p. 198 |
| 1981 | Torosaurus utahensis Tyson p. 1247 |
| 1986 | Torosaurus utahensis Tokaryk p. 195 |
| 1987 | Torosaurus utahensis Lehman p. 206 |
| 1994 | Torosaurus utahensis Derstler p. 133 |
| 1996 | Torosaurus utahensis Lehman p. 501–502 |
| 2005 | Torosaurus utahensis Sullivan et al. p. 400 |
| 2007 | Torosaurus utahensis Wu et al. p. 1260 |
| 2008 | Torosaurus utahensis Hunt and Lehman pp. 1128-1129 |
| 2011 | Torosaurus utahensis Farke p. 6 |
| 2012 | Torosaurus utahensis Longrich and Field p. 5 |
| 2014 | Torosaurus utahensis Currie and Koppelhus p. 1035 |
| 2014 | Triceratops utahensis Longrich p. 303 fig. 8 |
| 2018 | Torosaurus utahensis Lehman et al. p. 2216 |
| 2018 | Torosaurus utahensis Tweet and Santucci p. 717 |
| 2022 | Torosaurus utahensis Mallon et al. p. 158 |
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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
| Reference | Diagnosis | |
|---|---|---|
| T. M. Lehman 1996 | Large 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 2008 | Torosaurus 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
| estimate | equation | reference |
|---|---|---|
| 7.23 tons | Ceratopsidae femur circumference | Anderson et al. 1985 |
| 2.19 tons | Ceratopsidae humerus circumference | Anderson et al. 1985 |
| mean: 3.98 tons | ||
Measurements
| part | N | mean | |||||
|---|---|---|---|---|---|---|---|
| femur circumference | 1 | 376.0 | |||||
| humerus circumference | 1 | 274.0 |
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| Source: subo = suborder, o = order | |||||
| References: Marsh 1875, Norman and Weishampel 1991 | |||||
Age range: Late/Upper Maastrichtian or 72.20000 to 66.00000 Ma
Collections (3 total)
| Time interval | Ma | Country or state | Original ID and collection number |
|---|---|---|---|
| Late/Upper Maastrichtian | USA (Texas) | Pentaceratops sp. (85188) Torosaurus utahensis (69211) | |
| Late/Upper Maastrichtian | USA (Utah) | Ceratopsia indet. (type locality: 45719) |