Genus: Stegoceras LAMBE, 1902
Etymology: Greek, stego, “covered”, and Greek, ceras, “horn”: “covered horn.”
= Gravitholus WALL & GALTON, 1979
Etymology: Latin, gravis, “heavy”, and Greek, tholos, “dome”: “Heavy dome”.
= Gravilothus HUNT & LUCAS, 1992 (sic)
=Hanssuesia SULLIVAN, 2003
Etymology: In honor of Hans-Deiter Sues for his many contributions on dinosaurs, and in particular, for his work on pachycephalosaurs.
= Hanssuessia SULLIVAN, 2003 (sic)
= Ornatotholus GALTON & SUES, 1983
Etymology: Latin ornatus,“adorned, decorated” plus Greek, tholus “dome”: “adorned dome.”
= Onatotholus LUCAS, 1991 (sic)
= Ornathotholus HUNT & LUCAS, 1992 (sic)
= Stegoceros GALTON, 1975 (sic)
= Toodon DONG, 1979 (sic)
= Troodon GILMORE, 1924 non LEIDY, 1856
Etymology: Greek, troo, “wound, injure, pierce” and Greek, odon, “tooth”: “wounding tooth.”

Species: validum LAMBE, 1902
Etymology: Latin, validum, “strong.”
= Stegoceras validus LAMBE, 1902
= Tröödon validus (LAME, 1902) GILMORE, 1924

Holotype: CMN (NMC) 515

Locality: East side, below the mouth of Berry Creek, Dinosaur Provincial Park, Red Deer River, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material: Skullcap.

Paratype:

= Troodon validus GILMORE, 1924

UA (NMC?) 2

Locality: Quarry 058, vicinity of Steveville, Dinosaur Provincial Park, Red Deer River, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material: Skull, and lower jaws, two median dorsal vertebrae, 8 caudal vertebrae, scapula, coracoid, humerus, radius, and ulna, of the right fore limb, right ilium, left ischium, both femora, right tibia, both fibulae, four metatarsals, three phalanges and an ungual of the right pes, parts of 22 or more ribs, numerous segments of the abdominal cuirass, and fragmentary chevrons.

Referred material:

NMC 3: Greater portion of the parietal and frontal bones of a very large individual.

NMC 6: Frontal bone of a juvenile individual.

 


Locality: About 6 miles above Sand Creek, Dinoaur Provinicial Park, Red Deer River, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

AMNH 5388: Fronto-parietal area.

 

 

Locality: Cow Island, Fergus County, Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

USNM 11954: Frontal bones showing part of the endocranial cavity.

 


Locality: Red Deer River, Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

NMC 2374-2377: A basicranial fragment, the posterior border of a right squamosal, a portion of a left prefrontal (?), and the posterior border of parietals showing the suture with the left squamosal of young to fully adult individuals.

 


Locality: Below the mouth of Berry Creek, Dinosaur Provinical Park, Red Deer River, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

NMC 138: Frontoparietal area with the squamosals and postorbitals with an endocast of a juvenile.

NMC 158: Left squamosal.

 


Locality: South of Steveville, Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

NMC 1107: Parietals water-worn, of a juvenile.

NMC 2369: Most of the frontoparietal area of a juvenile.

NMC 2370-2372: Posterior lateral border of a left postorbital, a left squamosal, a portion of a parietal (?), and a portion of a left postorbital of young and adults.

 


Locality: Sand Creek, Dinosaur Provinical Park, Alberta Province, Canada.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMC 1108: Frontoparietal area of a juvenile.

NMC 1914: Right prefrontal.

NMC 2378: Posterior lateral border of a left postorbital (?) of a juvenile.

 


Locality: 2 1/2 miles east of Happy Jack Ferry, upper 50 feet of beds, Red Deer River, Alberta Province, Canada.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMC 8816: Frontoparietal area of a young adult.

 

 

Locality: Unknown, Canada.

Horizon: Unknown.

Biostratigraphy:

Age: Late Cretaceous.

Material:

Collections of Mr. Roy L. Fowler of Aldersyde, Alberta, Canada, No. 654: Frontoparietal area.

 

CURRIE & RUSSELL, 2005

Locality: Quarry unknown, Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

ROM 808, AMNH 5388: Skull caps.

 

GOODWIN, 1990

Locality: V77086, Kennedy Coulee, Hill County, north central Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

UCMP 131679: A right squamosal of an adult individual.

 


Locality: V77083, Kennedy Coulee, Hill County, north central Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

UCMP 131680: A right squamosal of a juvenile.

 


Locality: V78092, Kennedy Coulee, Hill County, north central Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

UCMP 130296: A partial right squamosal of a juvenile.

 

Locality: V81231, Turner Ranch, Liberty County, north central Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

UCMP 130050: A well-preserved medium-sized frontoparietal dome.

 

Locality: 16 miles (9.6 km) south of Shawmut, Wheatland County, North central Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

MOR 295: A pair of articulated but unfused moderately thickened frontals.

 

= Genus: Nova? GOODWIN, 1990

Locality: South bank of the Milk River, Super Coulee, Hill County, Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

UCMP 130051: A partial skull.


Note: Or possible new species of Stegoceras-grade pachycephalosaur (NIRODY, GOODWIN, JORNER, HUYNH, COLBERT, SMITH & EVANS, 2022).

 


LAMBE, 1918

Locality: Red Deer River, Alberta Province, Canada.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMC 2376: ?Left prefrontal.

NMC 2377: Small portion of parietal.

 

SAHNI, 1972

Locality: Clambank Hallow, Montana.

Horizon: Judith River Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

AMNH 8530: Teeth.

AMNH: Teeth.

 

SULLIVAN, 2003

Locality: Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

RTMP 95.12.147: Parietal.

RTMP 99.62.1: Incomplete frontoparietal with left squamosal.

CMN 2372, 2373, 2374, 2375, 28428, 38439, 38451, RTMP 66.21.66, 66.22.23, 79.8.37, 79.8.829, 80.16.902, 80.16.1011, 80.16.1168, 81.16.341, 81.16.496, 82.16.113, 82.16.260, 82.16.301, 82.19.28, 82.19.156, 82.20, 189, 82.20.386, 83.36.38, 83.67.1, 83.67.19, 84.67.20, 84.36.47, 84.121.6, 85.36.76, 85.44.25, 85.53.4, 85.56.118, 85.56.121, 85.58.68, 85.87.2, 86.36.87, 87.77.105, 86.77.106, 86.116.7, 87.36.369, 87.157.50, 88.36.65, 88.36.198, 88.116.149, 88.166.32, 89.36.115, 89.36.305, 89.50.156, 89.76.42, 89.116.88, 90.66.2, 90.107.97, 91.36.270, 91.146.10, 92.36.1089, 92.36.1125, 92.93.1, 92.109.9, 93.36.257, 93.85.12, 93.88.7, 94.12.13, 95.12.11, 95.12.147, 96.12.123, 97.12.70, 97.38.1, 98.12.75, 98.93.4, 99.62.1, 2999.26.01, UALVP-2:

Cf. S. validum

CMN 1074, 9959, RTMP 64.4.20, 80.16.1312, 80.16.1740, 81.16.145, 81.23.146, 82.16.108, 81.16.111, 81.16.123, 82.3.13, 84.121.21, 86.39.5, 87.7.2, 87.7.3, 92.2.3, 92.36.286, 93.75.55, UALVP-6,-8503, -8595, -8507:

?S. validum

RTMP 73.8.223, 83.209.3, 86.77.85, 86.146.7, 89.116.29, 96.169.2, 99.55.281:

SCHOTT, EVANS, GOODWIN, HORNER, BROWN & LONGRICH, 2011

RTMP 84.5.1: Fragmentary skull.

ROM 53555: Fragmentary skull of an old adult.

SCHOTT & EVANS, 2012

UALVP 49437, RTMP 90.119.20: Isolated parietals.

RTMP 1964.4.20: Fragmentary skull.

 

SCHOTT, EVANS, GOODWIN, HORNER, BROWN & LONGRICH, 2011, 2012

Locality: Steveville Railway Grade, Dinosaur Provincal Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group, 37 m above the contact with the Oldman Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

UCMZ(VP) 2008.001: Partial right frontal, fused parietals, right squamosal and right postorbital of a flat-headed juvenile.

UCMZ (VP) 2008.002: Isolated flat parietal.

RTMP 2000.57.61: Isolated flat parietal.

 

Locality: Stevevile area, Dinosaur Provincal Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group, approximately 40 m above the contact with the Oldman Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

UALVP 49531: Fragmentary skull of a flat-headed juvenile.

 

 

WALL & GALTON, 1979

Locality: West side of central area, Red Deer River, Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMC 1594: Parietal.

 

Locality: Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMC 8829: Partial parietal of a juvenile.

NMC 12351: Parietal of a juvenile.

 

 

Locality: Conray, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMC 9148: Fragmentary skull.

 


Locality: 1/2 mile (0.8 km) south of Steveville, Dinosaur Provincal Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

ROM 803: Fragmentary skull and endocast.

 

= Stygimoloch sp WILLIAMSON & CARR, 2006

Locality: Bonebed 23, Dinosaur Provincal Park, Newell County, Alberta State, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

RTMP 81.27.24: A partial frontoparietal dome consisting of the caudal portion of the parietals of a juvenile.


= Stegoceras browni WALL & GALTON, 1979
Etymology: In honor of Barnum Brown, collector of the type specimen.
= Ornatotholus browni (WALL & GALTON, 1979 ) GALTON & SUES, 1983
= Ornathotholus browni HUNT & LUCAS, 1992 (sic)

Holotype: AMNH 5450

Locality: Quarry unknown, left bank 75 ft (21.9m), above the Red Deer River, 1 mi (1.6 km) below Steveville, Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material: Frontoparietal region.

Referred specimens.

Locality: Section not recorded, tp. 17, rge. 3, west of 4th mer., White Rock Coulee, Cypress County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

RTMP P78.19.4: Right frontal.

 


Locality: Mouth of Sand Creek on Red Deer River, near Steveville, Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

YPM 22327: Incomplete left frontal.

 


GIFFIN, 1989

Locality: Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Middle Campanian Stage, middle Senonian subepoch, upper Gulf Epoch, Late Cretaceous.

Material:

RTMP 84.67.40: A partial right frontal.

RTMP 82.20.187: A complete parietal.

 


= Gravitholus albertae WALL & GALTON, 1979
Etymology: In reference to Alberta, a province in Canada.
= Gravilothus albertae HUNT & LUCAS, 1979 (sic)

Holotype: RTMP P72.27.1

Locality: Dinosaur Provincial Park, near Jenner Ferry, 50.45N, 111.12W, Newell County, Alberta Province, Canada.

Horizon: Oldman Formation, middle Judith River Group.

Biostratigraphy:

Age: Judithian age, Midle Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material: A frontoparietal dome with an endocast.

 

=Hanssuesia sternbergi (BROWN & SCHLAIKER, 1943) SULLIVAN, 2003
= Troodon sternbergi BROWN & SCHLAIKJER, 1943
Etymology: In honor of Charles M. Sternberg, who found the specimen.
= Stegoceras sternbergi (BROWN & SCHLAIKJER, 1943) STERNBERG, 1945

Holotype: NMC No. 8817

Locality: Dinosaur Provinical Park, southeast of Steveville, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material: A nearly complete frontoparietal.

Paratype: NMC No. 192

Locality: Dinosaur Provincial Park, below the mouth of Berry Creek, Red Deer River, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material: A frontoparietal area lacking the posterior margin.

Referred material:

CMNH 1953, 2379, 2379, 8945, RTMP 79.14.853, 87.36.363, 89.69.21, 2000.26.01, UALVP-3:

Cf. H. sternbergi

CM 1075, 8944, MOR 453, MOR 480, RTMP 85.36.240, 98.93.125, UALVP-8502:

 

 

Locality: Sand Creek, Newell County, Alberta Province, Canada.

Horizon: Dinosaur Park Formation, upper Judith River Group.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMC 2379: Frontoparietal area of a young adult.

 

= Genus: Nova GOODWIN, 1992/HORNER, VARRICCHIO & GOODWIN, 1992
(Indeterminate between Pachycephalosaurus and Stegoceras)

Locality: Montana.

Horizon: Two Medicine Formation.

Biostratigraphy:

Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

MOR 453, 480: 2 robust crania.

____________________________________________________________________________________

Species: novomexicanum JASINSKI & SULLIVAN, 2011
Etymology: In reference to the State of New Mexico, from which the holotype and paratype came.
= Genus: Nova? WILLIAMSON & CARR, 2002, SULLIVAN & LUCAS, 2006, JASINSKI & SULLIVAN, 2010

Holotype: NMMNH P-33898

Locality: NMMNH Locality 4716, Hunter Wash, San Juan County, New Mexico.

Horizon: Fossil Forest Member, Fruitland Formation.
Note: Horizon: De-na-zin Member, Lower Kirtland Formation (WILLIAMSON & CARR, 2002).

Biostratigraphy:

Age: Early Kirtlandian, Late Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material: Nearly complete frontoparietal.

Stegoceras novomexicanum (modified from JASINSKI,et al, 2011), Holotype: NMMNH P-33898

 

Paratype:

Locality: SMP locality 450 ("Target 8"), San Juan Basin, San Juan County, New Mexico.

Horizon: Fossil Forest Member, Upper Fruitland Formation.

Biostratigraphy:

Age: Early Kirtlandian, Late Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

SMP VP-2555: Greater posterior part of left frontal and anterior-most portions of left and right frontals.

 

Locality: SMP Locality 461 ("Target 9"), San Juan Basin, San Juan County, New Mexico.

Horizon: Hunter Wash Member, lower part of the Kirtland Formation.

Biostratigraphy:

Age: Early Kirtlandian, Late Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

SMP VP-2790: Incomplete parietal.

Referred material:

JASINSKI & SULLIVAN, 2016

Locality: NMMNH locality L-9218, San Juan Basin, San Juan County, New Mexico.

Horizon: Hunter Wash Member, lower part of the Kirtland Formation.

Biostratigraphy:

Age: Early Kirtlandian, Late Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

NMMNH P-70009: Incomplete frontoparietal.

 

Locality: SMP locality 450 ("Target 8"), San Juan Basin, San Juan County, New Mexico.

Horizon: Fossil Forest Member, Upper Fruitland Formation.

Biostratigraphy:

Age: Early Kirtlandian, Late Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

SMP VP-4370: Incomplete right frontoal fragment adn sagittal section of incomplete frontoparietal dome.