Genus: Exostinus COPE, 1873
Etymology:
= Harpaosaurus GILMORE, 1928
Etymology:
= Prionosaurus GILMORE, 1928
Etymology:
Species: lancensis GILMORE, 1928
Etymology: In reference to Lance Creek, Wyoming, where the specimen was found.
Referred material:
Locality: Lance Creek, Niobrara County, Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
USNM 10689: Right maxilla lacking anterior end.
Locality: UCMP V-5003, S 1/2, Sec. 20, T37N, R64W, Lance Creek, Powder River Basin, Niobrara County, Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
Number: Not given: A few fragments of jaws.
Locality: UCMP V-5620, Lull Quarry, near the head of a tributary of Buck Creek, Powder River Basin, Niobrara County (Formerly Converse County), Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
UCMP 46053: Left dentary broken posteriorly.
UCMP 46090: Anterior end of right dentary.
UCMP 46606: Anterior end of left dentary.
UCMP 46076: Anterior end of left dentary.
UCMP 47772: Posterior end of right dentary.
UCMP 47829: Almost complete right dentary, slightly broken anteriorly and posteriorly.
UCMP 50015: Complete left dentary of young individual.
UCMP 50016: Median fragment of left maxilla.
UCMP 50024: Posterior end of left maxilla.
UCMP 56091: Fragmentary parietal.
UCMP 56092: Fragmentary parietal.
Locality: UCMP V-5711, Bushy Tailed Blowout, Quarry area includes the floor of a small blowout approximately 10 yards northwest of the highest point on the ridge forming the northeastern side of the blowouts of loc. V-5003, S 1/2, Sec. 20, T37N, R64W, Lance Creek, Powder River Basin, Niobrara County, Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
UCMP 49847: Right maxillary fragment.
UCMP 49848: Anterior end of left dentary slightly broken anteriorly.
UCMP 49849: Median fragment of left maxilla showing sculpture.
UCMP 49850: Posterior end of left maxilla.
UCMP 49864: Fragment of left dentary.
UCMP 56093: Almost complete parietal.
A few jaw fragments.
GAO & FOX, 1996
UALVP 29847: Parietal.
UALVP 29849-29850: Incomplete maxillaries.
UALVP 29838: Dentary.
UALVP 29920: Jugal.
BREITHAUPT, 1982
Locality: East flank of Rock Springs Uplift, Sweetwater County, Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
UW 14136-14139: Right dentary fragments.
UW 14140: Left dentary fragment.
UW 14141: Left dentary fragment.
BRYANT, 1990
Locality: Eastern Montana.
Horizon: Hell Creek Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
UCMP 130734: Dentary fragment.
UCMP 123321: Maxilla.
UCMP 130731: Parietal.
ESTES, BERBERIAN & MESZOELY, 1969
Locality: Bug Creek Anthills locality, McCone County, Montana.
Horizon: Hell Creek Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
MCZ 3662a: Dentary and maxillary fragments.
MCZ 3662b: Frontal.
GAO & FOX, 1996
UALVP 29929: Frontal.
GAO & FOX, 1996
Localities: UC V-5616, Altman Blowout, this large blowout, site of the UCMP field-party camps from 1956 to 1960, is just east of the crest of the divide separating Lance Creek and Hancock Creek and 100 yards east of a dirt road. Fossils were found in anthills, talus, and sandstone exposed in the blowout, which is in the NE 1/4, Sec. 9, T37N, R64W, Eastern Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material:
UALVP 29848: A parietal.
SAHNI, 1972
Locality: Clambank Hollow, just north of the Judith River on the Missouri River in north-central Montana.
Horizon: Judith River Formation.
Biostratigraphy:
Age: Judithian age, Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.
Material:
AMNH 8497: Right maxillary fragment.
= Harpaosaurus parvus GILMORE, 1928
Etymology:
= Marpagosaurus parvus (GILMORE, 1928) ESTES, 1964
Etymology:Holotype: USNM 10803
Locality: "Peterson's Quarry," Lance Creek, Powder River Basin, Niobrara County, Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material: Right maxilla with 14 teeth.
= Prionosaurus regularis GILMORE, 1928
Etymology:Holotype: USNM 10750
Locality: Lance Creek, Niobrara County, Wyoming.
Horizon: Lance Formation.
Biostratigraphy:
Age: Lancian age, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.
Material: Incomplete maxilla.