Genus: Stygimoloch GALTON & SUES, 1983
Etymology: Greek, Stig- (Styx), the mythical underground river which shades passed on their way to hades, and Hebrew, moloch, “demon, horrid king”: Hell Creek demon.”
= Stenotholus GIFFIN, GABRIEL & JOHNSON, 1988
Etymology: Greek, stenos, “narrow" and Greek, tholos, “dome”: “narrow dome.”

Species: spinifer GALTON & SUES, 1983
Etymology: Latin, spinifer, "carrying thorns," in allusion to the spine-like projections the squamosal of this species.

Holotype: UCMP 119433

Locality: Harbicht Hill South No. 2, UCMP locality No. V-73100, NE 1/4, SW. 1/4, sec. 32, tp. 25N, RGE. 43E, McCone County, Montana.

Horizon: Lance Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Part of a left squamosal.

Referred material:

= Triceratops sp MARSH, 1891

Locality: 25 miles (40 km) above the mouth of Lance Creek, Niobrara County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

YPM 335: The postero-external corner of the left squamosal of immature individual.

 

GABRIEL & BERGAHUS, 1988, GOODWIN & JOHNSON, 1995, GOODWIN, BUCHHOLTZ & JOHNSON, 1998

Locality: MPM 3956, SW ¼, Section 8, Township 133N, Range 105W, Marmarth 7 ½ minute Quadrangle, near Marmarth, Slope County, North Dakota.

Horizon: Middle Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Martial:

Milwaukee Public Museum, MPM 8111: Squamosal, skull with horn core elements, skull.

Number: Not given: 2 additional skulls, 2 frontoparietal domes and associated postrcranial material.

 

GOODWIN, 1989

Locality: UCMP locality V84159, Garfield County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

UCMP 131163: A partial skull and associated squamosal.


Locality: UCMP Locality V83049, Garfield County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

UCMP 128383: A partial dome found with associated squamosal spikes, at least 12 caudal vertebrae and numerous fragments of thickened ossified tendons.
Note: Lonardelli, I., Wenk, H.-R., Lutterotti, L., and Goodwin, M., 2005 studied the tendons.

 

Locality: UCMP Locality V88027, Carter County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

UCMP 147063: A frontoparietal dome of a juvenile.


GOODWIN, BUCHHOLTZ & JOHNSON, 1998

Locality: UCMP Locality V65238, Niobrara County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

UCMP 147258: A squamosal horn fragment.

 


Locality: 0.4 km from the AMNH 5029 Tyrannosaurus quarry, Garfield County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

AMNH 21541: 3 partial cranial squamosal horns, many fragment of fusiform ossified tendons, 24 vertebral centra, most likely from the posterior dorsal and anterior caudal series, a single first? sacral, and 2 additional caudal vertebrae, proximal and distal ends of a right femur, the right tibia, and distal fragments of metatarsals I, II and III, a distal phalanx, distal coracoid, proximal fibula, and distal? Humerus of a juvenile.

 

KIRKLAND, pers com (1997)

Locality: Near Buffalo, South Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

DIS 102: Isolated left squamosal.

 

RUSSELL, 1995

Locality: “Sandy Quarry”, near Buffalo, South Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

Number: Not given: Nearly complete skull missing skullcap, and fragmentary skeleton.
Note: Or Pachycephalosaurus.

 

WROBLEWSKI,1998

Locality: Western Hanna Basin, Carbon County, South-central Wyoming.

Horizon: Ferris Formation.

Biostratigraphy:

Age: Lancian age, uppermost Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

Number: Not given:

 

Personal collection....

Locality: Garfield County, Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, lower Maastrichtian, Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material:

A cast from Fort Peck: Fragmentary skull.

Stygimoloch spinifer referred material (From a cast from Fort Peck).

 

= Stenotholus kohleri GIFFIN, GABRIEL & JOHNSON, 1987
= Stenotholus kohlerorum GIFFIN, GABRIEL & JOHNSON, 1987
Etymology: In honor of Terry and Mary Kohler major sponsored of Milwaukee Public Museum field work.

Holotype: Milwaukee Public Museum MPM 7111

Locality: MPM locality 3850, McCone County, Montana.

Horizon: Middle Hell Creek Formation.

Biostratigraphy:

Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: A well-preserved frontoparietal dome with partially preserved occipital and endocranial regions with an endocast.