PBDB Taxon

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Haplocanthosaurus priscus

Osteichthyes

Taxonomy

Haplocanthus priscus was named by Hatcher (1903). Its type specimen is CM 572, a partial skeleton, and it is a 3D body fossil. Its type locality is Felch Quarry 1, Garden Park, which is in a Kimmeridgian/Tithonian channel sandstone/claystone in the Morrison Formation of Colorado. It is the type species of Haplocanthosaurus, Haplocanthus.

It was recombined as Haplocanthosaurus priscus by Hatcher (1903), Hatcher (1903), Hatcher (1903), Mook (1916), Osborn and Mook (1919), Huene (1927), Hay (1930), Kuhn (1939), Steel (1970), Jain et al. (1979), Bonaparte (1980), McIntosh (1981), McIntosh (1990), Bakker (1990), Calvo and Salgado (1995), Carpenter (1997), Wilson and Sereno (1998), Carpenter (1999), Salgado (1999), Bonaparte (1999), Upchurch et al. (2004), Apesteguía (2005), Gallina and Apesteguía (2005), Chure et al. (2006), Mannion (2009), Canudo et al. (2010), Molnar (2011), Decker (2012), Foster and Wedel (2014), Cerda et al. (2015), Tschopp et al. (2019), Holwerda et al. (2021), Curtice et al. (2023), Boisvert et al. (2025).

Synonyms

Haplocanthosaurus utterbacki was named by Hatcher (1903). Its type specimen is CM 879/10380 and is a 3D body fossil. Its type locality is Felch Quarry 1, Garden Park, which is in a Kimmeridgian/Tithonian channel sandstone/claystone in the Morrison Formation of Colorado.

It was synonymized subjectively with Haplocanthosaurus priscus by McIntosh (1981), McIntosh (1990), Wilson and Sereno (1998), Upchurch et al. (2004), Foster and Wedel (2014), Boisvert et al. (2025).

Synonymy list

Year	Name and author
1903	Haplocanthosaurus priscus Hatcher
1903	Haplocanthus priscus Hatcher p. 1
1903	Haplocanthosaurus priscus Hatcher p. 6
1903	Haplocanthosaurus utterbacki Hatcher p. 27
1903	Haplocanthosaurus priscus Hatcher p. 100
1907	Haplocanthosaurus utterbacki Seitz p. 312
1916	Haplocanthosaurus priscus Mook p. 140
1916	Haplocanthosaurus utterbacki Mook p. 140
1919	Haplocanthosaurus priscus Osborn and Mook p. 388
1927	Haplocanthosaurus priscus Huene p. 457
1927	Haplocanthosaurus utterbacki Huene p. 457
1930	Haplocanthosaurus priscus Hay p. 192
1930	Haplocanthosaurus utterbacki Hay p. 192
1939	Haplocanthosaurus priscus Kuhn p. 86
1939	Haplocanthosaurus utterbacki Kuhn p. 86
1970	Haplocanthosaurus priscus Steel p. 66
1970	Haplocanthosaurus utterbacki Steel p. 66
1979	Haplocanthosaurus priscus Jain et al. p. 206
1980	Haplocanthosaurus priscus Bonaparte p. 76
1981	Haplocanthosaurus priscus McIntosh p. 11
1990	Haplocanthosaurus priscus Bakker p. 1
1990	Haplocanthosaurus priscus McIntosh p. 378
1995	Haplocanthosaurus priscus Calvo and Salgado p. 30 fig. 18
1997	Haplocanthosaurus priscus Carpenter p. 91
1998	Haplocanthosaurus priscus Wilson and Sereno p. 19
1999	Haplocanthosaurus priscus Bonaparte p. 158
1999	Haplocanthosaurus utterbacki Bonaparte p. 158
1999	Haplocanthosaurus priscus Carpenter p. 3
1999	Haplocanthosaurus priscus Salgado p. 210
2004	Haplocanthosaurus priscus Upchurch et al. p. 266
2005	Haplocanthosaurus priscus Apesteguía p. 252 fig. 12.1
2005	Haplocanthosaurus priscus Gallina and Apesteguía p. 158
2006	Haplocanthosaurus priscus Chure et al. p. 236
2006	Haplocanthosaurus pricus Mateus p. 231
2009	Haplocanthosaurus priscus Mannion p. 523 fig. 3
2010	Haplocanthosaurus priscus Canudo et al.
2011	Haplocanthosaurus priscus Molnar p. 305
2012	Haplocanthosaurus priscus Decker p. 8
2014	Haplocanthosaurus priscus Foster and Wedel p. 197
2015	Haplocanthosaurus priscus Cerda et al. p. 14
2019	Haplocanthosaurus priscus Tschopp et al. p. 12
2021	Haplocanthosaurus priscus Holwerda et al. p. 582
2023	Haplocanthosaurus priscus Curtice et al. p. 80
2025	Haplocanthosaurus priscus Boisvert et al. p. 6

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Rank	Name	Author
kingdom	Animalia	()
—	Bilateria
—	Eubilateria	Ax 1987
—	Deuterostomia
phylum	Chordata	Haeckel 1874
subphylum	Vertebrata
superclass	Gnathostomata
class	Osteichthyes
subclass	Sarcopterygii	()
subclass	Dipnotetrapodomorpha	(Nelson 2006)
subclass	Tetrapodomorpha	()
—	Tetrapoda
—	Reptiliomorpha
—	Anthracosauria
subclass	Amphibiosauria	Kuhn 1967
—	Cotylosauria	()
—	Amniota
—	Sauropsida
class	Reptilia
subclass	Eureptilia	()
—	Romeriida
—	Diapsida	()

Rank	Name	Author
—	Archosauromorpha	(Huene 1946)
—	Crocopoda
—	Archosauriformes	Gauthier 1986
—	Eucrocopoda
—	Archosauria	()
informal	Avemetatarsalia
—	Ornithodira
—	Dinosauromorpha
—	Dinosauriformes
—	Dinosauria	()
—	Saurischia	()
—	Sauropodomorpha	(Huene 1932)
—	Massopoda
—	Sauropodiformes
—	Sauropoda	()
—	Gravisauria
—	Eusauropoda
—	Neosauropoda
—	Diplodocoidea	()
genus	Haplocanthosaurus
species	priscus	()

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.

†Haplocanthosaurus priscus Hatcher 1903

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Invalid names: Haplocanthosaurus utterbacki Hatcher 1903 [synonym]

Diagnosis

Reference	Diagnosis
C. Boisvert et al. 2025	Haplocanthosaurus priscus can be diagnosed by the following characters: (1) middle dorsal vertebrae mildly opisthocoelous, and (2) distal end of ischia fused (see discussion below).

Measurements

No measurements are available

Composition:

hydroxyapatiteinfrao

Entire body:

yesg

Adult length:

10 to < 100infrao

Adult width:

10 to < 100infrao

Adult height:

10 to < 100infrao

Thickness:

thickinfrao

Architecture:

compact or denseinfrao

Form:

sphericalinfrao

Ontogeny:

accretion, modification of partsinfrao

Grouping:

gregariousinfrao

Environment:

terrestrialinfrao

Locomotion:

actively mobileinfrao

Life habit:

ground dwellinginfrao

Diet:

herbivoreinfrao

Reproduction:

oviparousinfrao

Dispersal:

direct/internalinfrao

Dispersal 2:

mobileinfrao

Created:

2005-08-24 13:35:49

Modified:

2005-08-24 15:35:49

Source: g = genus, infrao = infraorder

References: Peczkis 1995, Marsh 1875, Kiessling 2004

Age range: base of the Late/Upper Kimmeridgian to the top of the Early/Lower Tithonian or 152.21000 to 145.06000 Ma

Collections: one only

Time interval	Ma	Country or state	Original ID and collection number
Late/Upper Kimmeridgian - Early/Lower Tithonian	152.21 - 145.06	USA (Colorado)	Haplocanthus priscus, Haplocanthosaurus utterbacki (type locality: 28366)