# Bridger Formation

The Bridger Formation is a geologic formation in southwestern Wyoming. It preserves fossils dating back to the Bridgerian and Uintan stages of the Paleogene Period. The formation was named by American geologist Ferdinand Vandeveer Hayden for Fort Bridger, which had itself been named for mountain man Jim Bridger. The Bridger Wilderness covers much of the Bridger Formation's area.

## History

Before colonization, the lands making up the Bridger Formation had been inhabited by the Apsáalooke, Bannock, Eastern Shoshone, Hinono'eino, Očhéthi Šakówiŋ, Só'taeo'o, Tsétsêhéstâhese, and Ute nations. European settlers began to settle the area around the Bridger Formation in the 19th century, beginning with the establishment of the Oregon Trail in 1830. Fort Bridger – for which the formation would later be named – was established in 1843 by Jim Bridger and Louis Vasquez. In 1868, the remaining Indigenous communities in the area were displaced by the Treaty of Fort Bridger, removing them to the Fort Hall Indian Reservation and Wind River Indian Reservation.
The first documented fossils to be recovered from the Bridger Formation were discovered on 11 August 1849 by Captain Howard Stansbury, who documented the discovery of fossilized shells and wood in his expedition report while scouting out the region for the United States Army Corps of Topographical Engineers. In the early-1860s, trapper Jack Robinson claimed to have discovered a number of sites along the base of the Uinta Mountains where grizzly bears had been turned to stone. When these claims were called into question by judge William A. Carter, Robinson brought Carter a bag filled with the fossils. One of the specimens recovered by Robinson was a well-preserved skull which resembled that of a grizzly bear. Judger Carter invited Louis Agassiz to observe the local strata, but Agassiz declined as the journey would have involved riding horseback to the site, a mode of transportation Agassiz abhorred. Carter's son-in-law, Dr. J. Van A. Carter, would go on to send a number of fossils to palaeontologist Joseph Leidy at the University of Pennsylvania in 1869. These fossils included the first Bridgerian fossil taxa, Omomys carteri; and the skull discovered by Robinson, which was described as Palaeosyops paludosus. Another researcher responsible for sending off specimens was Dr. Joseph K. Corson, a close friend of Leidy's who hosted him and his family on two three to Fort Bridger in 1872, 1873, and 1879.
The Bridger Formation was described and named in 1869 by H.V. Hayden while conducting a geological survey in the region on behalf of the United States Geological and Geographical Survey of the Territories. The famously fossiliferous Bridger Formation attracted a number of famed palaeontologists including Henry Fairfield Osborn, William Berryman Scott, and F. Speir, Jr. The Bridger Formation also became a battleground in the Bone Wars between Edward Drinker Cope and Othniel Charles Marsh.
The Bridger Formation did not see a proper scientific mission until 1903, when Walter W. Granger and William Diller Matthew initiated a three-year survey of the strata, during which time Matthew identified the Bridger Formation's distinct members by using local limestone layers as marker beds. Later expeditions brought other researchers to the region, including Charles Lewis Gazin.

## Geology

The Bridger Formation overlies the Green River Formation and underlies the Bishop Conglomerate. The boundary with the former occurs in the mid-Eocene after the region completed a transition to a drier environment from a moist climate in the early Eocene. Limestone deposits like the Sage Creek Formation separate the three distinct members which make up the Bridger Formation: Blacks Fork (Bridger B), Twin Buttes (Bridger C & D), and Turtle Bluff (Bridger E). The limestone surrounding the Bridger Formation was deposited on the beds of lakes and ponds at the site during the Eocene. William Diller Matthew used this limestone as marker beds in his initial description of the Bridger Formation in 1909.
Portions formerly considered to be part of the Bridger Formation have since been reassigned to the nearby Uinta Formation.

## Palaeobiology

Dozens of Early Eocene (50.3 - 46.2 Ma) mammalian and invertebrate genera are known from the Bridger Formation.

## Eutherians
### Artiodactyls
#### Achaenodontidae

| Genus | Species | Location | Stratigraphic position | Material |
| Achaenodon | A. insolens | Wyoming | | AMNH 5143, fragmentary mandible |
| Achaenodon | A. robustus | Wyoming | | PU 10033, partial skull and mandible |
| Helohyus | H. lentus | Sweetwater County, Wyoming | | |
| Helohyus | H. milleri | Sweetwater County, Wyoming | Bridger B & C | |
| Helohyus | H. plicodon | southwestern Wyoming | Bridger B & C | |
| Parahyus | P. vagus | Wyoming | | YPM 10972, partial mandible |

#### Homacodontidae

| Genus | Species | Location | Stratigraphic position | Material |
| Antiacodon | A. pygmaeus | southwestern Wyoming | Bridger C & D | |
| Antiacodon | A. venustus | Sweetwater County, Wyoming | Bridger D | YPM 11765, a tooth |
| Homacodon | H. vagans | southwestern Wyoming | Bridger C & D | YPM 13129, skull and jaws |
| Microsus | M. cuspidatus | southwestern Wyoming | Bridger B - D | |

### Carnivoramorphans
#### stem Carnivoramophans

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Oodectes | O. herpestoides | Uinta County, Wyoming | | AMNH 140008, nearly-complete skull | |

#### Miacidae

| Genus | Species | Location | Stratigraphic position |
| Harpalodon | H. sylvestris | Washakie County, Wyoming | |
| Miacis | M. bathygnathus | Henry's Fork Hill, Sweetwater County, Wyoming | Bridger C |
| Miacis | M. edax | Wyoming | |
| Miacis | M. parvivorus | Lincoln and Uinta Counties, Wyoming | Bridger B & C |
| Miacis | M. vorax | Wyoming | |
| Miacis | M. vulpinus | Wyoming | |
| Miocyon | M. major | Blue Point Marker, Park County, Wyoming | |
| Uintacyon | U. jugulans | Henry's Fork Hill, Sweetwater County, Wyoming | Bridger C |
| Vulpavus | V. ovatus | Little Dry Creek, Uinta County, Wyoming | |
| Vulpavus | V. profectus | Uinta County, Wyoming | |

#### Viverravidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Viverravus | V. nitidus | Wyoming | | | |

### Carnivorans

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Palaearctonyx | P. meadi | Twin Buttes, Sweetwater Counties, Wyoming | | | |

### Cimolestans
#### Apatemyidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Apatemys | A. bellus | central and southern Wyoming | Bridger C | YPM 13512, partial mandible | |
| Apatemys | A. bellulus | southwestern and central Wyoming | Bridger C | YPM 13513, partial mandible USNM 22386, mandible | |

#### Esthonychidae

| Genus | Species | Location | Material |
| Megalesthonyx | M. hopsoni | Wyoming | |
| Tillodon | T. fodiens | Millersville, Uinta County, Wyoming | |
| Trogosus | T. castoridens | southwestern Wyoming | |
| Trogosus | T. gazini | Uinta County, Wyoming | USNM 364762, partial skeleton |
| Trogosus | T. hyracoides | Granger Station, Sweetwater County, Wyoming | |
| Trogosus | T. latidens | Lincoln and Sweetwater counties, Wyoming | |
| Trogosus | T. vetulus | Lincoln and Sweetwater counties, Wyoming | |

#### Pantolestidae

| Genus | Species | Location |
| Pantolestes | P. elegans | Wyoming |
| Pantolestes | P. intermedius | Wyoming |
| Pantolestes | P. longieundus | Wyoming |
| Pantolestes | P. natans | Wyoming |
| Pantolestes | P. phocipes | Wyoming |

### Creodontans
#### Hyaenodontidae

| Genus | Species | Location | Stratigraphic position | Material |
| Didelphodus | D. altidens | southwestern Wyoming | | |
| Entemodon | E. comptus | Honeycomb Buttes, Fremont County, Wyoming | | |
| Iridodon | I. datzae | Cathedral Bluffs, Sweetwater County, Wyoming | | UMMP 103465, mandible |
| Limnocyon | L. cuspidens | Ice Castle, Uinta County, Wyoming | | UMMP 103465, mandible |
| Limnocyon | L. medius | Henry's Fork Hill, Uinta County, Wyoming | Bridger D | |
| Limnocyon | L. velox | southwestern Wyoming | | |
| Limnocyon | L. verus | Uinta County, Wyoming | Bridger C | |
| Prolimnocyon | P. antiquus | Sweetwater County, Wyoming | | |
| Proviverra | P. americana | Wyoming | | |
| Sinopa | S. aculeatus | Wyoming | | |
| Sinopa | S. agilis | Uinta County, Wyoming | | |
| Sinopa | S. eximia | Wyoming | | |
| Sinopa | S. grangeri | Cottonwood Creek, Sublette County, Wyoming | | |
| Sinopa | S. insectivorus | Cottonwood Creek, Sublette County, Wyoming | | |
| Sinopa | S. major | southwestern Wyoming | | |
| Sinopa | S. minor | Church Buttes, Uinta County, Wyoming | | |
| Sinopa | S. pungens | Cottonwood Creek, Sublette County, Wyoming | | |
| Sinopa | S. rapax | southwestern Wyoming | | |
| Tritemnodon | T. hians | Wyoming | | |
| Tritemnodon | T. strenuus | Davis Ranch, Johnson County, Wyoming | | |

#### Oxyaenidae

| Genus | Species | Location |
| Aelurotherium | A. bicuspis | Henry's Fork, Uinta County, Wyoming |
| Aelurotherium | A. latidens | Grizzly Butte, Uinta County, Wyoming |
| Machaeroides | M. eothen | Twin Buttes, Sweetwater County, Wyoming |
| Machaeroides | M. simpsoni | Davis Ranch, Johnson County, Wyoming |
| Patriofelis | P. ferox | central and southwestern Wyoming |
| Patriofelis | P. ulta | southwestern Wyoming |

### Dinoceratans

| Genus | Species | Location | Stratigraphic position |
| Bathyopsis | B. fissidens | southwestern Wyoming | Bridger B. |
| Eobasileus | E. cornutus | southwestern Wyoming | |
| Uintatherium | U. anceps | southwestern Wyoming | Bridger C & D. |

### Eulipotyphlans
#### Erinaceomorpha

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Talpavus | T. nitidus | southwestern Wyoming | Bridger C | YPM 13511, fragmentary jaw | |

#### Geolabididae

| Genus | Species | Location | Stratigraphic position |
| Centetodon | C. bacchanalis | Hyopsodus Hill, Sublette County, Wyoming | |
| Centetodon | C. bembicophagus | southwestern Wyoming | |
| Centetodon | C. pulcher | southwestern Wyoming | Bridger C & D |
| Marsholestes | M. dasypelix | Uinta County, Wyoming | |

#### Nyctitheriidae

| Genus | Species | Location | Material |
| Nyctilestes | N. serotinus | Uinta County, Wyoming | |
| Nyctitherium | N. gunnelli | Uinta County, Wyoming | SDSNH 110393, partial mandible |
| Nyctitherium | N. priscus | Wyoming | |
| Nyctitherium | N. serotinum | central and southwestern Wyoming | |
| Nyctitherium | N. velox | Hyopsodus Hill, Sublette County, Wyoming | |

### Leptictidans

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Hypictops | H. syntaphus | Uinta County, Wyoming | Bridger D | | |
| Palaeictops | P. bridgeri | central Wyoming | | | |

### Macroscelids

| Genus | Species | Location |
| Scenopagus | S. curtidens | western Wyoming |
| Scenopagus | S. edenensis | southwestern Wyoming |
| Scenopagus | S. priscus | western Wyoming |

### Mesonychids

| Genus | Species | Location | Material |
| Harpagolestes | H. immanis | southern Wyoming | AMNH 13143, a partial skull and jaws |
| Harpagolestes | H. macrocephalus | Lincoln and Uinta counties, Wyoming | |
| Mesonyx | M. lanius | Wyoming | |
| Mesonyx | M. obtusidens | Uinta County, Wyoming | |
| Synoplotherium | S. canius | Bitter Creek, Sweetwater County, Wyoming | |

### Perissodactyls
#### Amynodontidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Orthocynodon | O. antiquus | Wyoming | | | |

#### Brontotheriidae

| Genus | Species | Location | Stratigraphic position | Material |
| Eotitanops | E. borealis | central Wyoming | | |
| Palaeosyops | P. fontinalis | western Wyoming | | |
| Palaeosyops | P. paludosus | central & southwestern Wyoming | | |
| Palaeosyops | P. robustus | southwestern Wyoming | | |
| Palaeosyops | P. ultimus | | | |
| Telmatherium | T. validum | Duncan Ranch, Fremont County, Wyoming | Bridger D | |
| Telmatherium | T. validus | Sweetwater County, Wyoming | Bridger D | YPM 11120, a partial skull |
| Mesatirhinus | M. megarhinus | Duncan Ranch, Fremont County, Wyoming | | PU 10008 |

#### Equidae

| Genus | Species | Location | Material |
| Oligotomus | O. cinctus | Wyoming | |
| Orohippus | O. agilis | Wyoming | YPM 1268, partial skeleton |
| Orohippus | O. ballardi | Wyoming | YPM 1268, partial skeleton |
| Orohippus | O. major | Millersville, Uinta County, Wyoming | YPM 11270, fragmentary maxilla |
| Orohippus | O. osbornianus | Blacks Fork, Uinta County, Wyoming | |
| Orohippus | O. procyoninus | Wyoming | |
| Orohippus | O. progressus | Wyoming | AMNH 12120, partial skull |
| Orohippus | O. pumilus | southwestern Wyoming | |
| Orohippus | O. sylvaticus | Uinta County, Wyoming | |
| Orohippus | O. uintanus | Wyoming | |

#### Hyopsodontidae

| Genus | Species | Location | Stratigraphic position |
| Hyopsodus | H. minusculus | southern and central Wyoming | Bridger B |
| Hyopsodus | H. lepidus | southwestern Wyoming | Bridger C |
| Hyopsodus | H. paulus | southwestern Wyoming | Bridger B - D |
| Hyopsodus | H. pygmaeus | Wyoming | |
| Hyopsodus | H. tonski | north and central Wyoming | |

#### Hyrachyidae

| Genus | Species | Location |
| Hyrachyus | H. eximius | southwestern Wyoming |
| Hyrachyus | H. minor | southwestern Wyoming |
| Hyrachyus | H. paradoxus | Wyoming |

#### Hyracodontidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Triplopus | T. cubitalis | Wyoming | | | |
| Triplopus | T. obliquidens | Wyoming | | | |

#### Isectolophidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Isectolophus | I. latidens | Lone Tree, Uinta County, Wyoming | Bridger D | PU 10251, fragmentary skull YPM 12563, partial skull | |
| Isectolophus | I. radinskyi | Lone Spring, Uinta County, Wyoming | Bridger D | | |

#### Tapiroidea

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Helaletes | H. nanus | central & southwestern Wyoming | | YPM 11080, partial jaws and cheek teeth YPM 11807, partial skeleton | |

### Palaeanodonta

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Brachianodon | B. westorum | southwestern Wyoming | | | |
| Metacheiromys | M. marshi | southwestern Wyoming | Bridger C | | |

### Pholidotans

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Tetrapassalus | T. proius | southwestern Wyoming | | | |

### Plesiadapiformes

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Alveojunctus | A. minutus | Vass Quarry, Hot Springs County, Wyoming | | | |

### Primates
#### Microsyopidae

| Genus | Species | Location | Stratigraphic position | Material |
| Microsyops | M. angustidens | Blackrock Meadows, Teton County, Wyoming | | |
| Microsyops | M. annectens | Sublette County, Wyoming | | |
| Microsyops | M. elegans | southwestern Wyoming | | YPM 11794, fragmentary mandible |
| Microsyops | M. knightensis | Honeycomb Buttes, Sweetwater County, Wyoming | | YPM 11794, fragmentary mandible |
| Microsyops | M. scottianus | southern Wyoming | | YPM 11794, fragmentary mandible |
| Uintasorex | U. parvulus | southwestern Wyoming | Bridger D | AMNH 12052, partial mandible |

#### Notharctidae

| Genus | Species | Location | Stratigraphic position | Material |
| Notharctus | N. robinsoni | southwestern Wyoming | | UW 3007, fragmentary mandibles |
| Notharctus | N. robustior | southwestern Wyoming | Bridger C & D | USNM 3750, fragmentary mandibles |
| Notharctus | N. tenebrosus | southwestern Wyoming | | |
| Notharctus | N. venticolus | Sweetwater County, Wyoming | | AMNH 4715b, partial upper and lower jaws |
| Smilodectes | S. gracilis | southwestern Wyoming | | YPM 11800, partial mandible |

#### Omomyidae

| Genus | Species | Location | Material |
| Anaptomorphus | A. aemulus | southwestern Wyoming | AMNH 5010, partial mandible |
| Anaptomorphus | A. westi | southwestern Wyoming | |
| Gazinius | G. amplus | central and southern Wyoming | |
| Gazinius | G. bowni | Uinta County, Wyoming | |
| Hemiacodon | H. engardae | Donna's Locality, Uinta County, Wyoming | UCM 67874, fragmentary mandible |
| Hemiacodon | H. gracilis | Uinta County, Wyoming | YPM 11806, fragmentary mandible |
| Omomys | O. carteri | southwestern Wyoming | |
| Trogolemur | T. myodes | Sweetwater County, Wyoming | AMNH 12399, partial mandible |
| Washakius | W. insignis | southwestern Wyoming | ANSP 10332, partial mandible AMNH 55672 |

### Rodentia
#### Cylindrodontidae

| Genus | Species | Location |
| Mysops | M. fraternus | Green Locality, Sweetwater County, Wyoming |
| Mysops | M. minimus | Grizzly Buttes, Uinta County, Wyoming |
| Mysops | M. parvus | Grizzly Buttes, Uinta County, Wyoming |

#### Ischyromyidae

| Genus | Species | Location | Material |
| Acritoparamys | A. wyomingensis | southern Wyoming | |
| Leptotomus | L. parvus | southwestern Wyoming | |
| Mytonomys | M. coloradensis | Van Houten's Locality, Park County, Wyoming | |
| Paramys | P. delicatior | southwestern Wyoming | |
| Paramys | P. delicatus | southwestern Wyoming | |
| Pseudotomus | P. hians | Cottonwood Creek, Sublette County, Wyoming | |
| Pseudotomus | P. horribilis | Grizzly Buttes, Uinta County, Wyoming | AMNH 5025, skull |
| Pseudotomus | P. robustus | southwestern Wyoming | |
| Quadratomus | Q. grandis | southwestern Wyoming | |
| Thisbemys | T. corrugatus | southern and central Wyoming | |
| Thisbemys | T. perditus | Sweetwater County, Wyoming | |

#### Paramyidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Franimys | F. buccatus | Wyoming | | | |

#### Reithroparamyidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Reithroparamys | R. delicatissimus | western Wyoming | | | |
| Reithroparamys | R. huerfanensis | southern Wyoming | | | |

#### Sciuravidae

| Genus | Species | Location |
| Knightomys | K. cuspidatus | Vass Quarry, Hot Springs County, Wyoming |
| Knightomys | K. depressus | central and southern Wyoming |
| Knightomys | K. huerfanensis | central and southern Wyoming |
| Knightomys | K. senior | central and southern Wyoming |
| Taxymys | T. lucaris | Sublette County, Wyoming |
| Tillomys | T. parvidens | Grizzly Buttes, Uinta County, Wyoming |
| Tillomys | T. senex | Sublette County, Wyoming |

## Metatherians
### Herpetotheriidae

Herpetotheriids reported from the Bridger Formation :
| Genus | Species | Location |
| Herpetotherium | H. innominatum | western Wyoming |
| Herpetotherium | H. knighti | western Wyoming |
| Peratherium | P. comstocki | central Wyoming |
| Peratherium | P. marsupium | southwestern Wyoming |

### Peradectidae

Peradectids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Armintodelphys | A. blacki | Lightning Butte, Sweetwater County, Wyoming | | | |
| Peradectes | P. chesteri | southwestern Wyoming | | | |

## Birds
### Gruiformes

Gruiformes reported from the Bridger Formation :
| Genus | Species | Location |
| Aletornis | A. bellus | Grizzly Buttes, Uinta County, Wyoming |
| Aletornis | A. gracilis | Henry's Fork, Sweetwater County, Wyoming |
| Aletornis | A. nobilis | Grizzly Buttes, Uinta County, Wyoming |
| Aletornis | A. pernix | Henry's Fork, Sweetwater County, Wyoming |
| Aletornis | A. venustus | Henry's Fork, Sweetwater County, Wyoming |

### Strigiformes

Owls reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Minerva | M. leptosteus | Grizzly Buttes, Uinta County, Wyoming | | YUPM 512, partial tibia | |
| Minerva | M. saurodosis | Lodge-Pole Trail, Uinta County, Wyoming | | ANSP 9131, partial humerus | |

## Fish
### Amiidae

Amia includes the genus jr synonyms Hypamia, Protamia, and Pappichthys. The amiids A. (Pr.) gracilis and A. (Pr.) media were first listed as Bridger Formation taxa, but were listed as from the Laney Member of the Green river Formation by Grande and Bemis (1998). The species A. (Pa.) cornsonii, A. depressus, A. (H.) elegans, and A. newberrianus are either Bridger formation or Green River Formation per Grande and Bemis.
| Genus | Species | Location | Material | Notes |
| Amia | A. (Pa.) cornsonii | "Upper Green River", southwestern Wyoming | USNM 3961, a centrum and dentary fragment (holotype) USNM 5476, 5475 and 3960 isolated centra (plesiotypes) | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |
| Amia | A. depressus | "Southwestern Wyoming" | Isolated "vertebrae and cranial bones" (Holotype, now lost?) | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |
| Amia | A. (H.) elegans | Dry Creek, Uinta County, Wyoming | ANSP 5580, isolated centrum | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |
| Amia | A. (Pr.) laevis | "Cottonwood Creek", Wyoming | USNM 3968 - Fragmentary premaxilla, dentary, quadrate, cranium, branchiostegal, pterygoid, and two centra | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |
| Amia | A. newberrianus | "Southwestern Wyoming" | ANSP 5632, vertebral centrum (Now lost?) | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |
| Amia | A. (Pa.) plicatus | Wyoming | AMNH 2539 - skull bones and vertebrae (syntypes) USNM 3958 - skull bones and vertebrae (syntypes) | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |
| Amia | A. (Pa.) sclerops | "bluffs of Cottonwood Creek", Wyoming | USNM 3965, partial left dentary | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |
| Amia | A. (Pr.) uintaensis | Dry Creek Cañon, Uinta County, Wyoming | ANSP 3151, 5558, 5622, 8044 - vertebral centra, a basioccipital (Syntypes) | Nomen dubium per Grande & Bemis (1998) as Amiinae indeterminate |

### Ariidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Rhineastes | R. peltatus | Wyoming | | | |
| Rhineastes | R. smithii | Wyoming | | | |

### Lepisosteidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Lepisosteus | L. atrox | Wyoming | | | |
| Lepisosteus | L. simplex | Wyoming | | | |

### Osteoglossidae

| Genus | Species | Location | Stratigraphic position | Material | Images |
| Phareodus | P. encaustus | Wyoming | | | |
| Phareodus | P. testis | Wyoming | | | |

## Reptiles
### Crocodilia

Crocodilians reported from the Bridger Formation :
| Genus | Species | Location |
| Crocodilus | C. elliottii | Wyoming |
| Crocodilus | C. grypus | Wyoming |
| Crocodilus | C. parvus | Wyoming |
| Crocodilus | C. sulciferus | Wyoming |
| Boverisuchus | B. vorax | Wyoming |
| Borealosuchus | B. wilsoni | Wyoming |
| Allognathosuchus | A. polyodon | Wyoming |
| Brachyuranochampsa | B. zangerli | Wyoming |

### Squamates
#### Anguidae

Anguids reported from the Bridger Formation :
| Genus | Species | Location | Material |
| Glyptosaurus | G. sphenodon | Henry's Fork, Sweetwater County, Wyoming | YPM 1051, partial maxilla and two teeth |
| Glyptosaurus | G. sylvestris | Big Horn and Uinta counties, Wyoming | YPM 526, left frontal YPM 521, fragmentary skull and jaws; several cervical and dorsal vertebrae; and several osteoderms YPM 522, a skull fragment; frontal; and two body scutes YPM 523, patch of cranial scutes |
| Paraglyptosaurus | P. princeps | southwestern Wyoming | YPM 524, partially-complete skull and jaw; dermal scutes USNM 6004, partially-complete skull YPM 525, partially-complete frontal bones |
| Xestops | X. vagans | southwestern Wyoming | YPM 541, partial skeleton AMNH 3819, left frontal |

#### Boidae

Boas reported from the Bridger Formation :
| Genus | Species | Location | Material |
| Boavus | B. brevis | Grizzly Buttes, Uinta County, Wyoming | PMNH 468, a thoracic vertebra |
| Boavus | B. occidentalis | Grizzly Buttes, Uinta County, Wyoming | PMNH 511, a dorsal vertebra YPM 467, vertebra YPM 2765, vertebra YPM 2766, vertebra |
| Lithophis | L. sargenti | Grizzly Buttes, Uinta County, Wyoming | YPM 2719, a thoracic vertebra |
| Protagras | P. lacustris | Cottonwood Creek, Sublette County, Wyoming | |

#### Chamaeleonidae

Chameleons reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Tinosaurus | T. pristinus | Uinta County, Wyoming | | PAS 9134, partial dentary and eight teeth | |
| Tinosaurus | T. stenodon | Henry's Fork Hill, Sweetwater County, Wyoming | | YUM 615, partial dentary and three teeth | |

#### Rhineuridae

Rhineurids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material |
| Lestophis | L. anceps | Grizzly Buttes, Uinta County, Wyoming | | YPM 520, vertebra |
| Lestophis | L. crassus | Marsh Creek, Uinta County, Wyoming | | YPM 531, cervical vertebra |
| Spathorhynchus | S. fossorium | Twin Buttes, Sweetwater County, Wyoming | Bridger B | |

#### Teiidae

Teiids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Iguanavus | I. exilis | Henry's Fork, Sweetwater County, Wyoming | | | |

#### Varanidae

Varanids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Saniwa | S. ensidens | southern Wyoming | | USNM 2185, partial skeleton and skull LACM CIT 5117, four vertebrae YPM 609, partial skeleton and a tooth YPM 610, fragmentary skeleton including several vertebrae YPM 611, partial vertebra YPM 612, partial skeleton | |
| Saniwa | S. major | Lodge-Pole Trail, Uinta County, Wyoming | | | |

### Testudines
#### Baenidae

Baenids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material |
| Baena | B. arenosa | Uinta County, Wyoming | | USNM 103, partial carapace AMNH 1675, carapace AMNH 5971, skull; carapace; vertebrae AMNH 5977, mostly-complete skeleton ANSP 10055, carapace CM 3227, partial carapace CM 3406, nearly-complete carapace |
| Chisternon | C. hebraicum | Cottonwood Creek, Sublette County, Wyoming | Bridger B | USNM 2275, partial carapace |
| Chisternon | C. undatum | Uinta County, Wyoming | | |

#### Carettochelyidae

Carettochelyids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Anosteira | A. ornata | southwestern Wyoming | | | |
| Anosteira | A. radulina | Ham's Fork, Lincoln County, Wyoming | | USNM 4096, partial carapace | |

#### Dermatemydidae

Dermatemydids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Baptemys | B. wyomingensis | Natrona and Uinta Counties, Wyoming | | AMNH 5934, complete carapace; fragmentary cervical vertebrae; pelvis AMNH 5967, partially-complete skull; crushed carapace YPM 484, nearly complete skull; crushed carapace with complete plastron; partial limb bones; one complete toe | |

#### Emydidae

Emydids reported from the Bridger Formation :
| Genus | Species | Location | Material |
| Emys | E. jaensi | Sweetwater County, Wyoming | USNM 962, partial carapace |
| Emys | E. latilabiatus | Blacks Fork, Uinta County, Wyoming | |
| Emys | E. stevensonianus | Fort Bridger, Uinta County, Wyoming | USNM 963, partial carapace USNM 965, partial carapace USNM 967, partial carapace |
| Emys | E. wyomingensis | Fort Bridger, Uinta County, Wyoming | ANSP 9777, plastron fragment |
| Hybemys | H. arenarius | Little Sandy Creek, Sublette County, Wyoming | |

#### Geoemydidae

Geoemydids reported from the Bridger Formation :
| Genus | Species | Location | Material |
| Echmatemys | E. haydeni | Levett Creek Quarry, Uinta County, Wyoming | USNM 109, partial carapace |
| Echmatemys | E. septaria | Uinta County, Wyoming | |
| Echmatemys | E. wyomingensis | Uinta County, Wyoming | |

#### Testudinidae

Testudinids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material |
| Hadrianus | H. allabiatus | Cottonwood Creek, Sublette County, Wyoming | Bridger B | |
| Hadrianus | H. corsoni | Cottonwood Creek, Sublette County, Wyoming | Bridger B | ANSP 10050, plastron |
| Hadrianus | H. octonaria | Cottonwood Creek, Sublette County, Wyoming | Bridger B | |
| Hadrianus | H. quadratus | Cottonwood Creek, Sublette County, Wyoming | Bridger B | |

#### Trionychidae

Trionychids reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material |
| Apalone | A. extensa | Grizzly Buttes, Uinta County, Wyoming | | AMNH 5951, partial carapace |
| Apalone | A. heteroglypta | Wyoming | | |
| Apalone | A. postera | Uinta County, Wyoming | Bridger C | AMNH 6133, partial carapace |
| Apalone | A. trionychoides | Cottonwood Creek, Sublette County, Wyoming | | USNM 4094, partial carapace |
| Axestemys | A. byssina | Blacks Fork, Sweetwater County, Wyoming | | USNM 4089, partial skeleton USNM 12589, fragmentary skull and partial plastron |
| Axestemys | A. cerevisia | Opal, Lincoln County, Wyoming | | UW 2382, carapace with plastron; cervical vertebra; partial girdles |
| Axestemys | A. salebrosa | Dry Creek, Uinta County, Wyoming | Bridger C | AMNH 3941, partial carapace |
| Axestemys | A. uintaensis | Little Dry Creek, Uinta County, Wyoming | | |
| Hummelichelys | H. annae | Sweetwater County, Wyoming | | FMNH P 27241, nearly-complete carapace with plastron |
| Hummelichelys | H. ellipticus | Grizzly Buttes, Uinta County, Wyoming | | AMNH 1117, carapace |
| Hummelichelys | H. grangeri | Cottonwood Creek, Sublette County, Wyoming | | AMNH 3942, partial carapace |
| Hummelichelys | H. guttatus | Uinta County, Wyoming | | |
| Plastomenus | P. molopinus | Grizzly Buttes, Uinta County, Wyoming | | AMNH 6072, fragmentary carapace |
| Plastomenus | P. oedemius | Sublette and Uinta Counties, Wyoming | Bridger B | AMNH 3937, a partial carapace |
| Plastomenus | P. tantillus | Cottonwood Creek, Sublette County, Wyoming | Bridger B | AMNH 6018, partial carapace |
| Plastomenus | P. thomasi | Sublette and Uinta Counties, Wyoming | | AMNH 5980, nearly-complete carapace with plastron |
| Plastomenus | P. visendus | Rattlesnake Hills, Fremont County, Wyoming | | AMNH 1895, carapace |
| Platypeltis | P. serialis | | | |
| Platypeltis | P. trepida | Grizzly Buttes, Uinta County, Wyoming | | AMNH 5925, partial carapace |
| Trionyx | T. concentricus | Cottonwood Creek, Sublette County, Wyoming | | AMNH 1049, partial carapace |

### Incertae sedis

Reptiles of uncertain placement reported from the Bridger Formation :
| Genus | Species | Location | Stratigraphic position | Material | Images |
| Naocephalus | N. porrectus | Cottonwood Creek, Sublette County, Wyoming | Bridger B | | |