Species: insiliens HAY, 1908
Etymology:

Holotype: AMNH 1108

Locality: Seven Mile Creek, about 5 miles north of Cheyenne River, about 40 miles west of the town Edgemont, Fall County, South Dakota.

Horizon: Lance Formation.

Biostratigraphy:

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

Material: An almost complete shell.

Referred material:

BYRANT, 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 117102: Anterior carapace.

 

GAFFNEY, 1972/ WIMAN, 1933

Locality: Meyers creek, etwa 3 miles orberhalb einer Stelle, die als “South Branch, Meyers Creek, about 4 miles above cattle ranch” bezeichnet wurde, San Juan County, New Mexico.

Horizon: Lower Kirtland Formation.

Biostratigraphy:

Age: Kirtlandian age, Upper Campanian Stage- Lower Maastrichtian Stage, Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

Number: Not given: A partial shell.

 

LANGSTON, STANDHARDT & STEVENS, 1989

Locality: Big Bend National Park, Brewster County, Texas.

Horizon: Lower Aguja Formation.

Biostratigraphy:

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

Material:

Number: Not given:

 

LEHMAN, 1981

Locality: San Juan County, New Mexico.

Horizon: Hunter Wash Local Fauna, Hunter Wash Member, Lower Kirtland Formation.

Biostratigraphy:

Age: Kirtlandian age, Upper Campanian Stage- Lower Maastrichtian Stage, Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

Number: Not given:

 

MATEER, 1981

Locality: South branch of Hunter Wash, San Juan County, New Mexico.

Horizon: Below the Naashoibito Member, Lower Kirtland Formation.

Biostratigraphy:

Age: Kirtlandian age, Upper Campanian Stage- Lower Maastrichtian Stage, Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

PMU.R22, R23: Carapaces and plastrons.

 

 

= Baena longicauda RUSSELL, 1934
Etymology:

Holotype: NMC 8678

Locality: SE 1/4, Sec. 23, Tp. 1, Rge, %, W. 3rd Meridian, Morgaon Creek, east branch of Rocky Creek, Saskatchewan Province, Canada.

Horizon: Ravenscrag Formation.

Biostratigraphy:

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

Material: A partial shell with limb material and caudal vertebrae.

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Species: rapiens HAY, 1908
Etymology:

Holotype: AMNH 6066

Locality: Ojo Alamo Trading Post, San Juan Basin, San Juan County, New Mexico.

Horizon: De-na-zin Member, Latest Kirkland Formation (Alamo Wash Formation).

Biostratigraphy:

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

Material: Fragmentary shell.

Referred material:

PMU R22: incomplete carapace and plastron.

ADRIAN, SMITH & McDONALD, 2025

Locality: San Juan County, New Mexico.
Note: Exact locality data are on file at teh BLM and the respective repositories.

Horizon: Menefee Formation.

Biostratigraphy:

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

Material:

NHMMNH P-97384: Right half of anterior plastral lobe and partial nuchal.

GAFFNEY, 1972/WIMAN, 1933

Locality: South Side Alamo wash, 3 miles above Havlies Store, San Juan County, New Mexico.

Horizon: Lower Kirtland Formation.

Biostratigraphy:

Age: Kirtlandian age, Upper Campanian Stage- Lower Maastrichtian Stage, Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

Number: Not given: A partial shell.

 

= Thescelus cf. T. rapiens SULLIVAN, JASINSKI, & LUCAS, 2013

Locality: 393, New Mexico.

Horizon: Hunter Wash Member, Kirtland Formation.

Biostratigraphy:

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

Material:

SMP VP-1553: Carapace fragments and associated fragments.

 

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Species:  hemispherica GILMORE, 1935
Etymology:

Holotype: USNM 12818

Locality: 3 m northeast of Hunter's Store (Bisti Post Office), SW 1/4, T 24N, R13W,  San Juan County, New Mexico.

Horizon: Hunter Wash Member, Kirtland Formation.

Biostratigraphy:

Age: Kirtlandian age, Upper Campanian Stage- Lower Maastrichtian Stage, Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material: Incomplete carapace and plastron.

Referred material:

= Thescelus cf. T. hemispherica SULLIVAN, JASINSKI, & LUCAS, 2013

Locality: ?, New Mexico.

Horizon: Hunter Wash Member, Kirtland Formation.

Biostratigraphy:

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

Material:

PMU.R 23: Incomplete carapace and plastron.