Species: vaccinsulensis COPE, 1876 (nomen dubium)
Etymology:
= Plesiosaurus vaccinsulensis (COPE, 1876)

Holotype: In AMNH

Locality: Montana.

Horizon: Judith River Formation.

Biostratigraphy:

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

Material: Weathered vertebral centrum.
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Species: laramiensis BROWN, 1905
Etymology:

Holotype: AMNH 982

Locality: Hell Creek, a tributary of the Missouri River, 130 miles northwest of Miles City, Garfield County, Montana.

Horizon: Tullock Formation.

Biostratigraphy:

Age: Paleocene Epoch, Early Paleogene.

Material: A nearly complete skull and skeleton.

Paratype: AMNH 981: Skull and skeleton lacking only parts of the tail and both hind feet.

Referred material:

SMM P62.10.1:

SMM P63.13.1:

SMM P63.14.1:

SMM P64.20.1:

SMM P65.3.1:

SMM P65.9.1:

SMM P68.55.1:

SMM P68.68.1:

SMM P69.10.1:

SMM P69.13.1:

SMM P69.14.1:

 

HOGANSON, ERICKSON & HOLLAND, 2007

Locality: NDSFC locaity EM196, Emmons County, North Dakota.

Horizon: Fox Hills Formation.
Note: Interfingering of Western Interior Seaway with the Hell Creek Formation.

Biostratigraphy:

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

Material:

ND 02-17.10: Semi-articulated pelvic girdle, including ilia, pubes, and isch, femora and right fibula.

 

 

= ?Champsosaurus cf. laramiensis WHITMORE, 1988

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

Horizon: Lance Formation.

Biostratigraphy:

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

SDSM 12406: 1 dentary fragment.

SDSM 12407: 4 dentary fragments.

SDSM 12399: 3 humeri fragments.

SDSM 12397: 1 femur.

SDSM 12398: 1 femur fragment.

SDSM 12393: 1 cervical vertebrae.

SDSM 12391: 21 dorsal vertebrae.

SDSM 12392: 4 caudal vertebrae.

SDSM 12394: 4 vertebral fragments.

SDSM 12400: 2 rib fragments.

 

Locality: SDSM Locality V852, Hanson Locality, Niobrara County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

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

SDSM 12401: 1 femur fragment.

SDSM 12389: 1 cervical fragments.

SDSM 12390: 8 dorsal vertebrae.

SDSM 12395: 2 vertebral fragments.

SDSM 12402: 2 rib fragments.

 

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

Horizon: Lance Formation.

Biostratigraphy:

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

SDSM 12405: 1 humeral fragment.

SDSM 12404: 1 metatarsal.

SDSM 12396: 1 dorsal vertebra.

 

Locality: SDSM Locality V851A, Lower Zerbst Locality, Niobrara County, Wyoming.

Horizon: Lance Formation.

Biostratigraphy:

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

Material:

SDSM 12403: 1 rib 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, upper Maastrichtian Stage, uppermost Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

SDSM 12780: 1 maxillary fragment.

SDSM 12705: 1 vertebra.

SDSM 12706: 2 rib fragments.

 

= ?Champsosaurus australis COPE, 1881
Etymology: Latin, australis, "the south."

Holotype:

Locality: Puerco, New Mexico.

Horizon:

Biostratigraphy:

Age: Paleocene Epoch, Early Paleogene.

Material: 11 Vertebrae.

 

= ?Champsosaurus puercensis COPE, 1882
Etymology: In reference to Pueroc, New Mexico.

Holotype:

Locality: Puerco, New Mexico.

Horizon:

Biostratigraphy:

Age: Paleocene Epoch, Early Paleogene.

Material: Fragments and badly weathered vertebrae.

 

= ?Champsosaurus saponensis COPE, 1882
Etymology:

Holotype:

Locality: Puerco, New Mexico.

Horizon:

Biostratigraphy:

Age: Paleocene Epoch, Early Paleogene.

Material: 6 cervicals and dorsals.

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Species: albertensis PARKS, 1927
Etymology: In reference to the Alberta Province, Canada.

Holotype: ROM

Locality: Red Deer River, Alberta Province, Canada.

Horizon: Edmonton Formation.

Biostratigraphy:

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

Material: 5th cervical to the second caudal vertebrae, all the dorsal and most of the cervical ribs, the pectoral and pelvic girdles complete, both humeri, 1 ulna, 1 radius, 1 incomplete manus, both tibiae, 1 fibula, a number of scattered caudal vertebrae, chevrons, and transverse processes, a few bones of the tarsus and pes, and a series of abdominal ribs.

Referred material:

= Champsosaurus albertensis? GAO & FOX, 1998

Locality: Red Deer River Valley, Lsd 15, Sec. 14, Tp28, R20, W4, Drumheller, Wheatland County, Alberta Province, Canada.

Horizon: Horseshoe Canyon Formation, Edmonton Group.

Biostratigraphy:

Age: Edmontonian age, lower Maastrichtian Stage, Upper Senonian subepoch, Upper Gulf Epoch, Late Cretaceous.

Material:

RTMP 86.12.11: Skeleton of a large Champsosaurus, with incomplete skull, both mandibles, partial vertebral column, incomplete girdles, and limb bones.

RTMP 95.11.1: Incomplete postorbital part of skull.

UALVP 830: Fragmentary skull.

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Species: natator PARKS, 1933
Etymology: Latin, natator, "swimming."

Holotype: RTMP 81.47.1
Note: Was ROM 856 (Old ROM 5737), then Texas Memorial Museum, TMM 41269.

Locality: Q047, 3 sec. 11. tp. 21, rge, 12, W. 4th mer., Dinosaur Provinical Park, Red Deer River, 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: Incomplete skull, most of the vertebral column and dorsal ribs, pelvis, and incomplete femora.

Referred material:

AMNH 5364: Fragmentary skull and skeleton.

ROM 5738:

ROM 5739:

SMM P68.55.1:

 

Locality: Sec. 35, tp. 20, rge. 12, W. 4th mer., south side of Little Sandhill Creek, Red Deer River Valley, 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:

NMC 8919: Anterior part of skeleton, including skull, lower jaw, vertebral column to 20th vertebra, pectoral girdle and front limbs, and parasternal ribs.

 

Locality: Near Centre of Sec. 29, tp. 21, rge. 12. W. 4th mer., west side of Red Deer River, 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:

NMC 8921: Fragmentary skull.

 

Locality: 4 miles southwest of mouth of Little Sandhill Creek, presumably in sec. 26, tp. 20, rge, 12, W. 4th mer, Red Deer River Valley, 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:

NMC 8922: Fragmentary skull and parts of skeleton.

NMC 2785: Right mandibular ramus.

 

= Champsosaurus sp. cf. C. natator EBERTH, BRAMAN, & TOKARK, 1990

Locality: Muddy Lake, Kindersley County, west-central Saskatchewan Province, Canada.

Horizon: Judith River Formation.

Biostratigraphy:

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

Material:

Number: Not given:

 

GAO & FOX, 1998

Locality: Sec. 27. Tp. 21, R12, W4, Dinosaur Provincial Park, Newell County, Alberta Province, Canada.

Horizon: Oldman Formation, middle Judith River Group.

Biostratigraphy:

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

Material:

UALVP 33929: Incomplete skull.

UALVP 1937: Incomplete right dentary with partial splenial.

 

= ?Champsosaurus annectens COPE, 1876
Etymology: Latin, annectens, "linking or joining."

Holotype:

Locality: Montana.

Horizon: Judith River Formation.

Biostratigraphy:

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

Material: Centrum of an axis and vertebrae.

 

= ?Champsosaurus profundus COPE, 1876
Etymology: Latin, profundus, "deep, profound."

Holotype:

Locality: Montana.

Horizon: Judith River Formation.

Biostratigraphy:

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

Material: Vertebrae.

 

= ?Champsosaurus breficollis COPE, 1876
Etymology:

Holotype:

Locality: Montana.

Horizon: Judith River Formation.

Biostratigraphy:

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

Material: Weathered axis centrum.

 

= Champsosaurus ambulator BROWN, 1905
Etymology: Latin, ambulator, "walking."

Holotype: AMNH 983

Locality: Hell Creek, a tributary of the Missouri River, 130 miles northwest of Miles City, Montana.

Horizon: Tullock Formation.

Biostratigraphy:

Age: Lower Paleocene Epoch, Early Paleogene.

Material: A nearly complete skull and skeleton.

(Note: KATSURA, 2004 believes this to be a female C. laramiensis)

= Champsosaurus inflatus PARKS, 1933
Etymology: Latin, inflatus, "inflate, puffed up, swollen."

Holotype:

Locality: Alberta Province, Canada.

Horizon: Judith River Formation, Judith River Group.

Biostratigraphy:

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

Material:

 

= Champsosaurus inelegans PARKS, 1933
Etymology: Latin, inelegans, "inelegant."

Holotype:

Locality: Alberta Province, Canada.

Horizon: Judith River Formation, Judith River Group.

Biostratigraphy:

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

Material: A third cervical.

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Species: gigas ERICKSON, 1972
Etymology: Greek, gigas, "giant."

Holotype: SMM P71.2.1

Locality: Ft. Union Gp., NE 1/4SW1/4 Sec. 28, T. 141 N., R. 104 W., Golden Valley County, North Dakota.

Horizon: Sentinel Butte Formation.

Biostratigraphy:

Age: Upper Paleocene Epoch, Early Paleogene.

Material: A partial skull and lower jaw and a nearly complete skeleton of a young adult animal.

Referred material:

SMM P60.2004: Postcranial skeleton lacking portions of limbs, girdles and the feet.

PU 16239: Skull with partial lower jaw.

PU 16240: Skull.

SDSM 53508: Postcranial skeleton lacking most of the anterior half.

USNM 20521: Partial postcranial skeleton.

FMNH PR93: Partial skull and skeleton.

FMNH P26132: Partial skull and skeleton.

ERICKSON, 1985

Locality: 1 mile north of Wannagan Creek Quarry in section 7, T 141 N, R 102 W, Billings County, North Dakota.

Horizon: Bullion Creek (Tongue River) Formation.

Biostratigraphy:

Age: Upper Paleocene Epoch, Early Paleogene.

Material:

SMM P77.33.24: Skull and skeleton.

 

GAO & FOX, 1998

Locality: UAR2L locality, NW ¼, Sec. 28, Tp1, R6, W2, near the village of Roche Percee, Southeastern Saskatchewan Province, Canada.

Horizon: Ravenscrage Formation.

Biostratigraphy:

Age: Late Tiffanian, Late Paleocene Epoch, Early Paleogene.

Material:

UALVP 33931: A nearly complete skull, and many unnumbered disarticulated vertebrae.

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Species: dolloi SIGOGNEAU-RUSSELL, 1979
Etymology: In honor of Louis Dollo.

Holotype: IRHN R21

Locality: Belgium.

Horizon:

Biostratigraphy:

Age: Inferior Thanetian (Landenian) Stage, Upper Paleocene Epoch, Lower Palegoene Period, Lowermost Tertiary Sub-era, Lowermost Cenozoic era.

Material: Prefrontal, centrum of atlas, 7 cervical vertebrae, interclavical, scapula, humerus, ilium, femur missing anterior end, and phalanges.

Referred material:

IRHN R22: Clavicle and interclavicle.

IRHN R82: Cranium base, pterygoid, mandible, atlas, scapula, coracoid, humerus, ilium, femur, and incomplete skeleton.

IRHN R83: Mandible.

IRHN R81: Fragment of mandible, and isolated postcrainal material.

IRHN R85: Caudal vertebrae.

IRHN R 84/116: Fragment of mandible.

IRHN R84/33: Interclavicle.

IRHN R84/40: Distal end of femur.

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Species: tenuis ERICKSON, 1981
Etymology: Latin, tenuis, "narrow, thin."

Holotype: SMM P79.14.1

Locality: NE1/4 SW1/4 Sec. 4, T. 143N, R.101!, Billings County, North Dakota.

Horizon: Bullion Creek Formation.

Biostratigraphy:

Age: Late Tiffanian, Late Paleocene Epoch, Early Paleogene.

Material: A nearly complete skull and a partial skeleton.
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Species: lindoei GAO & FOX, 1998
Etymology: In honor of L. A. Lindoe, who found and collected the holotype in 1962.

Holotype: UALVP 931

Locality: Outcrop in Dinosaur Provincial Park, Q129, in Sec. 17, Tp20, R12, W 4, Newell County, Alberta Province, Canada.

Horizon: Oldman Formation, middle Judith River Group.

Biostratigraphy:

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

Material: Nearly complete skull with mandibles, most of the vertebral column, pectoral and pelvic girdles, and limbs.

Referred material:

UALVP 33928: Incomplete skull with broken snout.

RTMP 80.16.631: Skull of a juvenile missing the anterior tip and left and right side of posterior portion of the skull.

RTMP 88.116.48: Incomplete right mandible.

RTMP 94.163.1: Small but well-preserved skull lacking anterior extremity of snout.

 

Locality: Dinosaur Provincial Park, Q189, 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:

RTMP 87.36.41: Nearly complete skull with premaxillae and left temporal region missing.

 

DUDGEON, MALLON & EVANS, 2023

Locality: North of Dupuyer, in either Section 29 or 30, Township 29N, Range 7W, Pondera County, Montana.

Horizon: Two Medicine Formation, Judith Group.

Biostratigraphy:

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

Material:

UALVP 931: Nearly complete skull and skeleton, missing tip of tail and front legs except for on manus.

 

= Champsosaurus natator RUSSELL, 1956

Locality: Dinosaur Provincial Park, Sec. 28, tp. 21, rge 12, W. 4th mer. west side of Red Deer River, 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:

CMN (old NMC) 8920: Small skull, and almost complete skeleton.

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Species: norelli BROWNSTEIN, 2022
Etymology: In honor of Mark Norell, curator of vertebrate paleontology at the American Museum of Natural Histtory, for his extensive contributions to tetrapod paleontology and evolution.

Holotype: YPM YPPU 16511

Locality: Fritz Quarry, Park County, Wyoming.

Horizon: Silver Coulee beds horizon, Polecat Bench Formation.

Biostratigraphy:

Age: Late Tiffanian Stage, Late Paleocene Epoch, Early Paleogene Period, Early Tertiary Sub-era, Cenozoic Era.

Material: Complete skull, mandibles, and partial skeleton.