Species: speciosa HAY, 1908
Etymology:

Holotype: AMNH 6136

Locality: 25 miles east of Pryor, Pryor County, Montana.

Horizon: Kootenai (Cloverly) Formation.

Biostratigraphy:

Age: Cashenranchian, Aptian-Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous.
Note: According to Hay, 1908, Morrison Formation, Late Jurassic.

Material: Entoplastron.

Referred material:

Locality: YPM 63-19, NW 1/4, Sec. 28, T 58, N., R 95 W, 30 yards NW of YPM 63-18, Big Horn County, Wyoming.

Horizon: Cloverly Formation.

Biostratigraphy:

Age: Cashenranchian, Aptian-Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous.

Material:

YPM 5385: Right and left epiplastra.

YPM 5432, 5433, 5434: Fragmentary pleurals.

OMNH 60695: Shell fragment.

 

Locality: YPM 64-18, SW 1/4, Sec. 33, T 4S, R 29 E, 350 yards east of YPM 64-17, 1 mile south of Cashen Ranch house, Big Horn County, Montana.

Horizon: Cloverly Formation.

Biostratigraphy:

Age: Cashenranchian, Aptian-Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous.

Material:

YPM 5437: Humerus head, femur head and many shell fragments.

 

Locality: YPM 64-39, NE 1/4, Sec 22, T 5S, R 28 E, 700 yards east of Thor Lande Ranch, on Push Creek, Big Horn County, Wyoming.

Horizon: Cloverly Formation.

Biostratigraphy:

Age: Cashenranchian, Aptian-Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous.

Material:

YPM 5518: Humerus head, femur head and many shell fragments.

 

Locality: YPM 64-56, NW 1/4, Sec 17, T 7S, R 24E, 1.5 miles NE of Tom Edwards ranch, 260 yards west of YPM 64-54, Carbon County, Montana.

Horizon: Cloverly Formation.

Biostratigraphy:

Age: Cashenranchian, Aptian-Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous.

Material:

YPM 5431: Right and left eiplastra.

 

EBERTH, 1987

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:

Number: Not given:

 

JOYCE, CHAPMAN, MOODY & WALKER, 2011

Locality: Maryland.

Horizon: Arundel Clay Facies, Potomac Formation.

Biostratigraphy:

Age: Aptian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous.

Material:

 

Locality: Texas.

Horizon: Trinity Group.

Biostratigraphy:

Age: Aptian-Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous.

Material:

FMNH PR273: Nearly complete skeleton, including skull.

 

Locality: Utah.

Horizon: Cedar Mountain Formation.

Biostratigraphy:

Age: Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous-Cenomanian Stage, Uppermiddle Gallic Subepoch, Lowermost Gulf Epoch, Middle Cretaceous.

Material:

OMNH 55501, 27145: Shell fragments.

 

Locality: Utah.

Horizon: Straight Cliffs Formation.

Biostratigraphy:

Age: Albian Stage, middle Gallic subepoch, lower Cretaceous Epoch, Early Cretaceous-Cenomanian Stage, Uppermiddle Gallic Subepoch, Lowermost Gulf Epoch, Middle Cretaceous.

Material:

OMNH 6115-6118: Shell fragments.

 

Locality: Alberta Province, Canada.

Horizon: Milk River Formation.

Biostratigraphy:

Age: Aquilian age, Late Santonian-?Campanian Stage, Senonian subepoch, Upper Gulf epoch, Late Cretaceous.

Material:

RTMP 92.69.8, 2006.61.20: Shell fragments.

 

Locality: Alberta Province, Canada.

Horizon: Foremost Formation.

Biostratigraphy:

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

Material:

RTMP 1970.3.1, 1990.60.7, 2000.16.1: Numerous shell fragments.

RTMP 1973.8.212: Shell fragments.

 

Locality: Montana.

Horizon: Two Medicine Formation.

Biostratigraphy:

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

Material:

USNM 7704: Portion of Carapace.

 

SUAREZ, FREDERICKSON, DIFELLI, PITTMAN, NYDAM, HUNT-FOSTER & MOGAN, 2021

Locality: Briar Site, ca. 18 km NNW Nashville, 34.09°N, 93.88°W, Howard County, Southwest Arkansas.

Horizon: Uppermost Holly Cross Formation, Trinity Group.

Biostratigraphy:

Age: Albian Stage, Middle Gallic Subepoch, Late Early Cretaceous Epoch, Early Cretaceous.

Material:

UA-2016-13-1: Unusual costal or marginal fragment.

UA-2016-13-001: Unknown fragment.

UA-2016013-3:

UA-2016-13-4: Thick costal fragment.

UA-2016-13-5:

UA-2016-13-6:

UA-2016-13-7: Unusually shpaed margenial fragment.

UA-2016-13-8:

UA-2016-13-9: First neural bone.

UA-2016-13-12: Nuchal fragment.

UA-2016-13-259, 2016-13-235: Several large carapace and plastron fragments.

 

WILLIAMSON, 1997

Locality: NMMNH Locality L-3033, San Juan Basin, New Mexico.

Horizon: Allison Member, Menefee Formation.

Biostratigraphy:

Age: Early Campanian Stage, Senonian Subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

NMMNH P-25053: A nearly complete costal.

NMMNH P-42161: Shell fragment.

 

STINCHCOMB, PARRIS, GRANDSTAFF & DENTON, 1994

Locality: Chronister farm, sec. 26, T31N, R9E, about 1 mile north of Glen Allen, Bollinger County, Missouri.

Horizon: McNairy sand Member, Ripley Formation.

Biostratigraphy: Middle-Uppermiddle Mosasaurus Acme-zone.

Age: Navesinkian age, Early Maastrichtian Stage? Upper Senonian Subepoch, Gulf Epoch, Late Cretaceous.

Material:

Number: Not given: