Species: distincta HAY, 1908
Etymology:

Holotype: USNM 5732

Locality: Lance Creek, Niobrara County (old Converse County), Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

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

Material: Fragment of one costal plate and a portion of one hypoplastron or hyoplastron.

Referred material:

BREITHAUPT, 1982

Locality: UW Locality V-79032, east flank of Rock Springs Uplift, Sweetwater County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

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

Material:

UW 14117: Miscellaneous carapace fragments.

 

BYRANT, 1990

Locality: Eastern Montana.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

UCMP 129204: Hyohyoplastron.

 

McCORD, TEGOWSKI & SCARBOROUGH, 2002

Localites: MSM 99-75, Adobe Canyon, Santa Rita Mountains, Santa Cruz County, Arizona.

Horizon: Fort Crittenden Formation.

Biostratigraphy:

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

Material:

MSM p99-75: Plastron fragment.

ASDM 1949, 1188 : Shell fragments.

 

HOLYROD & HUTCHISON, 2002

Locality: V 86050, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

177928:

 

Locality: V 86051, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

177946-177948:

 

Locality: V 86073, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

172144:

Locality: V 86075, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

177916:

 

Locality: V 86095, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

172195:

 

Locality: V 91092, western North Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

177845:

 

HUTCHISON & HOLROYD, 2003

Locality: UCM locality 73175, Denver Basin, Colorado.

Horizon: Laramie Formation.

Biostratigraphy:

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

Material:

UCM 13747b: Ho- or hypoplastron fragment and 2 costal fragments.

 

Locality: UCM locality 77062, Denver Basin, Colorado.

Horizon: Laramie Formation.

Biostratigraphy:

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

Material:

UCM 38725: Most of right dentary and symphyseal part of left dentary.

UCM 42334: Medial and latral parts of hypoplastron and anterior fragment of xiphiplastron.

UCM 42341: Plastral and costal fragments.

 

Locality: DMNH 1513, Denver Basin, Colorado.

Horizon: Denver Formation, D1 sequence.

Biostratigraphy:

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

Material:

DMNH 45108: Anteriolateral quadrant of the left xiphiplastron.

 

 

Locality: DMNH 2389, Denver Basin, Colorado.

Horizon: Denver Formation, D1 sequence.

Biostratigraphy:

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

Material:

DMNH 45126: Medial part of a left hyoplastron.

 

JOYCE & LYSON, 2018

Locality: NDGS locality 64, Slope County, North Dakota.

Horizon: 25 m of the Hell Creek Formation.

Biostratigraphy:

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

Material:

NDGS 353; A nearly complete carapace.

 

Locality: DMNH loality 7179, Fallon County, Montana.

Horizon: Hell Creek Formation,

Biostratigraphy:

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

Material:

DMNH EPV.125902: A fragmentary, disarticulated shell, including among others, a partial right nuchal and the distal portions of costls I-III.

 

Locality: DMNH locaclity 5873, Slope County, North Dakota.

Horizon: Hell Creek Formation,

Biostratigraphy:

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

Material:

DMNH EPV.125900: A nearly complete left hyo/hypoplastron and left xiphiplastron.

DMNH EPV.125901: A partial right hyo/hypoplastron.

 

Locality: PTRM loclaity V86006, Slope County, North Dakota.

Horizon: Hell Creek Formation,

Biostratigraphy:

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

Material:

PTRM 2767: A fragmented, partial carapace.

 

Locality: UCMP locality V79116, Garfield County, Montana.

Horizon: Hell Creek Formation,

Biostratigraphy:

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

Material:

UCMP 130112, 130113: A left hypoplastron and right and left xiphiplastra.

 

Loclaity: UCMP locality V84187, McCone County, Montana.

Horizon: Hell Creek Formation,

Biostratigraphy:

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

Material:

UCMP 131614: A left hypoplastron.

 

Locality: UCMP locality V87080, McCone County, Montana.

Horizon: Hell Creek Formation,

Biostratigraphy:

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

Material:

UCMP 134502: An assortment of shell fragments including left costals IV and VII.

 

 

 

STENERSON & O’CONNER, 1994

Locality: Northwestern South Dakota.

Horizon: Hell Creek Formation.

Biostratigraphy:

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

Material:

Number: Not given:

 

WHITMORE, 1988

Locality: SDSM Locality V851, Zerbst Locality, east of the Cheyenne River, Niobrara County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

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

Material:

SDSM 12471: 2 carapace fragments.

SDSM 12472: 1 plastron fragment.

SDSM 12473: 3 miscellaneous carapace and plastron fragment.

 

Locality: SDSM Locality V853, Leonard’s Lizard Site, Niobrara County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

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

Material:

SDSM 12474: 1 plastron fragment.

 

Locality: SDSM Locality V685, Greasewood Creek Locality, northern side of the south fork of the Greasewood Creek, Niobrara County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

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

Material:

SDSM 12699: 2 plastron fragments.

 

WROBLEWSKI, 1998

Locality: Western Hanna Basin, Carbon County, Southcentral Wyoming.

Horizon: Ferris Formation.

Biostratigraphy:

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

Material:

Number: Not given: