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Coryphodon incisor Willwood Formation of Wyoming Eocene Age (56 to 33.9 million years ago) The tooth with the root sits 7/8" tall and measures approximately 5/8" across the bottom. Coryphodon (from Greek "point", and "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of mammal. Coryphodon was a pantodont, a member of the world's first group of large browsing mammals. It migrated across what is now northern North America, replacing Barylambda, an earlier pantodont. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia. Coryphodon is known from many specimens in North America and considerably fewer in Europe, Mongolia, and China. It is a small to medium-sized coryphodontid who differs from other members of the family in dental characteristics. Coryphodon had one of the smallest brain/body ratios of any mammal, living or extinct, possessing a brain weighing just 90 grams (3.2 oz) and a body weight of around 500 kilograms (1,100 lb). Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: †Cimolesta Suborder: †Pantodonta Family: †Coryphodontidae Genus: †Coryphodon

Coryphodon incisor Willwood Formation of Wyoming Eocene Age (56 to 33.9 million years ago) The tooth with the root sits 7/8" tall and measures approximately 5/8" across the bottom. Coryphodon (from Greek "point", and "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of mammal. Coryphodon was a pantodont, a member of the world's first group of large browsing mammals. It migrated across what is now northern North America, replacing Barylambda, an earlier pantodont. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia. Coryphodon is known from many specimens in North America and considerably fewer in Europe, Mongolia, and China. It is a small to medium-sized coryphodontid who differs from other members of the family in dental characteristics. Coryphodon had one of the smallest brain/body ratios of any mammal, living or extinct, possessing a brain weighing just 90 grams (3.2 oz) and a body weight of around 500 kilograms (1,100 lb). Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: †Cimolesta Suborder: †Pantodonta Family: †Coryphodontidae Genus: †Coryphodon

Coryphodon incisor Willwood Formation of Wyoming Eocene Age (56 to 33.9 million years ago) The tooth with the root sits 7/8" tall and measures approximately 5/8" across the bottom. Coryphodon (from Greek "point", and "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of mammal. Coryphodon was a pantodont, a member of the world's first group of large browsing mammals. It migrated across what is now northern North America, replacing Barylambda, an earlier pantodont. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia. Coryphodon is known from many specimens in North America and considerably fewer in Europe, Mongolia, and China. It is a small to medium-sized coryphodontid who differs from other members of the family in dental characteristics. Coryphodon had one of the smallest brain/body ratios of any mammal, living or extinct, possessing a brain weighing just 90 grams (3.2 oz) and a body weight of around 500 kilograms (1,100 lb). Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: †Cimolesta Suborder: †Pantodonta Family: †Coryphodontidae Genus: †Coryphodon

Coryphodon incisor Willwood Formation of Wyoming Eocene Age (56 to 33.9 million years ago) The tooth with the root sits 7/8" tall and measures approximately 5/8" across the bottom. Coryphodon (from Greek "point", and "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of mammal. Coryphodon was a pantodont, a member of the world's first group of large browsing mammals. It migrated across what is now northern North America, replacing Barylambda, an earlier pantodont. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia. Coryphodon is known from many specimens in North America and considerably fewer in Europe, Mongolia, and China. It is a small to medium-sized coryphodontid who differs from other members of the family in dental characteristics. Coryphodon had one of the smallest brain/body ratios of any mammal, living or extinct, possessing a brain weighing just 90 grams (3.2 oz) and a body weight of around 500 kilograms (1,100 lb). Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: †Cimolesta Suborder: †Pantodonta Family: †Coryphodontidae Genus: †Coryphodon

Coryphodon incisor Willwood Formation of Wyoming Eocene Age (56 to 33.9 million years ago) The tooth with the root sits 7/8" tall and measures approximately 5/8" across the bottom. Coryphodon (from Greek "point", and "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of mammal. Coryphodon was a pantodont, a member of the world's first group of large browsing mammals. It migrated across what is now northern North America, replacing Barylambda, an earlier pantodont. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia. Coryphodon is known from many specimens in North America and considerably fewer in Europe, Mongolia, and China. It is a small to medium-sized coryphodontid who differs from other members of the family in dental characteristics. Coryphodon had one of the smallest brain/body ratios of any mammal, living or extinct, possessing a brain weighing just 90 grams (3.2 oz) and a body weight of around 500 kilograms (1,100 lb). Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: †Cimolesta Suborder: †Pantodonta Family: †Coryphodontidae Genus: †Coryphodon

Coryphodon incisor Willwood Formation of Wyoming Eocene Age (56 to 33.9 million years ago) The tooth with the root sits 7/8" tall and measures approximately 5/8" across the bottom. Coryphodon (from Greek "point", and "tooth", meaning peaked tooth, referring to "the development of the angles of the ridges into points [on the molars].") is an extinct genus of mammal. Coryphodon was a pantodont, a member of the world's first group of large browsing mammals. It migrated across what is now northern North America, replacing Barylambda, an earlier pantodont. It is regarded as the ancestor of the genus Hypercoryphodon of Mid Eocene Mongolia. Coryphodon is known from many specimens in North America and considerably fewer in Europe, Mongolia, and China. It is a small to medium-sized coryphodontid who differs from other members of the family in dental characteristics. Coryphodon had one of the smallest brain/body ratios of any mammal, living or extinct, possessing a brain weighing just 90 grams (3.2 oz) and a body weight of around 500 kilograms (1,100 lb). Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: †Cimolesta Suborder: †Pantodonta Family: †Coryphodontidae Genus: †Coryphodon

Diplomystus dentatus Fish Fossil GREEN RIVER formation, Kemmerer, Wyoming USA Eocene age (56 Million years ago) Diplomystus is an extinct genus of freshwater clupeomorph fish distantly related to modern-day extant herrings, alewives, and sardines. The genus was first named and described by Edward Drinker Cope in 1877. There are seven species of Diplomystus: D. dentatus (Cope, 1877), D. birdii, D. dubetreiti, D. shengliensis (Chang 1983), D. kokuraensis (Uyeno 1979), D. primotinus (Uyeno 1979), and D. altiformis. D. dentatus (Cope, 1877) is well known from lower Eocene deposits from the Green River Formation in Wyoming. Specimens range from larval size to 65 cm and are commonly found in close association with the extinct herring Knightia sp. The Green River Formation is the remnant of a large lake whose mud would eventually be transformed into soft calcite-bearing shale. D. kokuraensis (Uyeno 1979), D. primotinus (Uyeno 1979), and D. altiformis were dominant members of an Early Cretaceous lake fauna (the "Diplomystus-Wakinoichthys Fauna") in what is now Japan and Korea. Dimensions: 4.6 Inches Long & 3 Inches Wide (Plate) Fish is 4.2 Inches Long & 1.5 Inch Wide. Diplomystus Dentatus morphology, including its upturned mouth, is prototypic of a surface feeding fish. The genus is herrings that likely fed on small surface-dwelling fish as Knightia is evidenced by numerous fossils found with Knightia is the stomach or mouth. The unusual chemistry of fossil lake prevented decay and scavenging of dead organisms while millimeter-thick layers of alternating limestone matter slowly accumulated. The result is laminated limestones that contained the highest concentration of fossil fish in the world. These fish, other aquatic organisms, and associated geologic features make Fossil Lake the world's best Paleogene record of the freshwater lake ecosystem. Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Clupeiformes Family: †Ellimmichthyidae Genus: †Diplomystus Species: †dentatus

Phareodus encaustus fish fossil Green River Formation, Kemmerer Wyoming Eocene Age (56 Million Years ago) Phareodus is a genus of freshwater fish from the Eocene to the Oligocene of Australia, Europe and North America. This genus includes at least four species, P. testis (Leidy, 1873) and P. encaustus of North America, P. muelleri of Europe, and P. queenslandicus of Australia. Representatives have been found from the middle Eocene to the Oligocene of Australia, Europe and North America, including the Green River Formation in Wyoming, United States P. testis was a freshwater fish with an oval outline, a small head, and a slightly pointed snout. Its dorsal and anal fins were situated posteriorly, with the anal fin being larger. Its caudal fin was slightly forked. It had small pelvic fins but long, narrow pectoral finsPhareodus belongs to the osteoglossids, which are represented today by the Arawana. Arawana is found in tropical and semitropical fresh waters of South America, central Africa, Southeast Asia, and northern Australia. Phareodus lived during the Eocene Epoch and is about 55 million years old They can be found in the fine-grained limestone layers of the River Formation. Fifty million years ago ancient Fossil Lake existed in what is now southwest Wyoming. Of its estimated maximum extent of 930 square miles, approximately 500 square miles of sediment remain. The 230 square miles across the center of the ancient lake-bed contain exceptionally fossiliferous sediments and associated geologic features including deltas, beaches, springs, and rocks from the center and near shore environments. Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Infraphylum: Gnathostomata Superclass: Osteichthyes Class: Actinopterygii Family: Osteoglossidae Genus: †Phareodus Species: †encaustus

Phareodus encaustus fish fossil Green River Formation, Kemmerer Wyoming Eocene Age (56 Million Years ago) Phareodus is a genus of freshwater fish from the Eocene to the Oligocene of Australia, Europe and North America. This genus includes at least four species, P. testis (Leidy, 1873) and P. encaustus of North America, P. muelleri of Europe, and P. queenslandicus of Australia. Representatives have been found from the middle Eocene to the Oligocene of Australia, Europe and North America, including the Green River Formation in Wyoming, United States P. testis was a freshwater fish with an oval outline, a small head, and a slightly pointed snout. Its dorsal and anal fins were situated posteriorly, with the anal fin being larger. Its caudal fin was slightly forked. It had small pelvic fins but long, narrow pectoral finsPhareodus belongs to the osteoglossids, which are represented today by the Arawana. Arawana is found in tropical and semitropical fresh waters of South America, central Africa, Southeast Asia, and northern Australia. Phareodus lived during the Eocene Epoch and is about 55 million years old They can be found in the fine-grained limestone layers of the River Formation. Fifty million years ago ancient Fossil Lake existed in what is now southwest Wyoming. Of its estimated maximum extent of 930 square miles, approximately 500 square miles of sediment remain. The 230 square miles across the center of the ancient lake-bed contain exceptionally fossiliferous sediments and associated geologic features including deltas, beaches, springs, and rocks from the center and near shore environments. Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Infraphylum: Gnathostomata Superclass: Osteichthyes Class: Actinopterygii Family: Osteoglossidae Genus: †Phareodus Species: †encaustus

Phareodus encaustus fish fossil Green River Formation, Kemmerer Wyoming Eocene Age (56 Million Years ago) Phareodus is a genus of freshwater fish from the Eocene to the Oligocene of Australia, Europe and North America. This genus includes at least four species, P. testis (Leidy, 1873) and P. encaustus of North America, P. muelleri of Europe, and P. queenslandicus of Australia. Representatives have been found from the middle Eocene to the Oligocene of Australia, Europe and North America, including the Green River Formation in Wyoming, United States P. testis was a freshwater fish with an oval outline, a small head, and a slightly pointed snout. Its dorsal and anal fins were situated posteriorly, with the anal fin being larger. Its caudal fin was slightly forked. It had small pelvic fins but long, narrow pectoral finsPhareodus belongs to the osteoglossids, which are represented today by the Arawana. Arawana is found in tropical and semitropical fresh waters of South America, central Africa, Southeast Asia, and northern Australia. Phareodus lived during the Eocene Epoch and is about 55 million years old They can be found in the fine-grained limestone layers of the River Formation. Fifty million years ago ancient Fossil Lake existed in what is now southwest Wyoming. Of its estimated maximum extent of 930 square miles, approximately 500 square miles of sediment remain. The 230 square miles across the center of the ancient lake-bed contain exceptionally fossiliferous sediments and associated geologic features including deltas, beaches, springs, and rocks from the center and near shore environments. Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Infraphylum: Gnathostomata Superclass: Osteichthyes Class: Actinopterygii Family: Osteoglossidae Genus: †Phareodus Species: †encaustus

Diplomystus Dentatus Fish Fossil GREEN RIVER formation, Kemmerer, Wyoming USA Eocene age (56 Million years ago) Diplomystus is an extinct genus of freshwater clupeomorph fish distantly related to modern-day extant herrings, alewives, and sardines. The genus was first named and described by Edward Drinker Cope in 1877. There are seven species of Diplomystus: D. dentatus (Cope, 1877), D. birdii, D. dubetreiti, D. shengliensis (Chang 1983), D. kokuraensis (Uyeno 1979), D. primotinus (Uyeno 1979), and D. altiformis. D. dentatus (Cope, 1877) is well known from lower Eocene deposits from the Green River Formation in Wyoming. Specimens range from larval size to 65 cm and are commonly found in close association with the extinct herring Knightia sp. The Green River Formation is the remnant of a large lake whose mud would eventually be transformed into soft calcite-bearing shale. D. kokuraensis (Uyeno 1979), D. primotinus (Uyeno 1979), and D. altiformis were dominant members of an Early Cretaceous lake fauna (the "Diplomystus-Wakinoichthys Fauna") in what is now Japan and Korea. Dimensions: 4.6 Inches Long & 3 Inches Wide (Plate) Fish is 4.2 Inches Long & 1.5 Inch Wide. Diplomystus Dentatus morphology, including its upturned mouth, is prototypic of a surface feeding fish. The genus is herrings that likely fed on small surface-dwelling fish as Knightia is evidenced by numerous fossils found with Knightia is the stomach or mouth. The unusual chemistry of fossil lake prevented decay and scavenging of dead organisms while millimeter-thick layers of alternating limestone matter slowly accumulated. The result is laminated limestones that contained the highest concentration of fossil fish in the world. These fish, other aquatic organisms, and associated geologic features make Fossil Lake the world's best Paleogene record of the freshwater lake ecosystem. Kingdom: Animalia Phylum: Chordata Class: Actinopterygii Order: Clupeiformes Family: †Ellimmichthyidae Genus: †Diplomystus Species: †dentatus

Merycoidodontoidea (Oreodont) Fossil Jaw Bone with Teeth SITE LOCATION: Badlands of South Dakota, USA TIME PERIOD: Eocene age (40-53 million years ago) Data: Weight: .9 Ounces, Dimensions: 1.9 Inches Long & 1.2 Inches Wide. Merycoidodontoidea, sometimes called "oreodonts," or "ruminating hogs", is an extinct superfamily of prehistoric cud-chewing artiodactyls with short faces and fang-like canine teeth. As their name implies, some of the better known forms were generally hog-like, and the group was once thought to be a member of Suina, the pigs, peccaries and their ancestors, though recent work indicates they were more closely related to camels. Oreodonts are extinct Artiodactylids most closely related to camels and pigs, with no close relatives living today. All are herbivorous, browsing on a diet of leaves and young shoots. Oreodonts fed on different types of vegetation than many modern artiodactyls do and therefore occupied an ecologically different niche than many living ungulates. Found only in North America, oreodonts would eventually rival the large and diverse extant populations of modern bovid artiodactyls in Africa (antelopes, wildebeest, and buffalo) or the equally diverse populations of deer and goats of Asia. Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Artiodactyla Family: †Merycoidodontidae

Merycoidodontoidea (Oreodont) Fossil Jaw Bone with Teeth SITE LOCATION: Badlands of South Dakota, USA TIME PERIOD: Eocene age (40-53 million years ago) Data: Weight: .9 Ounces, Dimensions: 1.9 Inches Long & 1.2 Inches Wide. Merycoidodontoidea, sometimes called "oreodonts," or "ruminating hogs", is an extinct superfamily of prehistoric cud-chewing artiodactyls with short faces and fang-like canine teeth. As their name implies, some of the better known forms were generally hog-like, and the group was once thought to be a member of Suina, the pigs, peccaries and their ancestors, though recent work indicates they were more closely related to camels. Oreodonts are extinct Artiodactylids most closely related to camels and pigs, with no close relatives living today. All are herbivorous, browsing on a diet of leaves and young shoots. Oreodonts fed on different types of vegetation than many modern artiodactyls do and therefore occupied an ecologically different niche than many living ungulates. Found only in North America, oreodonts would eventually rival the large and diverse extant populations of modern bovid artiodactyls in Africa (antelopes, wildebeest, and buffalo) or the equally diverse populations of deer and goats of Asia. Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Artiodactyla Family: †Merycoidodontidae

Merycoidodontoidea (Oreodont) Fossil Jaw Bone with Teeth SITE LOCATION: Badlands of South Dakota, USA TIME PERIOD: Eocene age (40-53 million years ago) Data: Weight: .9 Ounces, Dimensions: 1.9 Inches Long & 1.2 Inches Wide. Merycoidodontoidea, sometimes called "oreodonts," or "ruminating hogs", is an extinct superfamily of prehistoric cud-chewing artiodactyls with short faces and fang-like canine teeth. As their name implies, some of the better known forms were generally hog-like, and the group was once thought to be a member of Suina, the pigs, peccaries and their ancestors, though recent work indicates they were more closely related to camels. Oreodonts are extinct Artiodactylids most closely related to camels and pigs, with no close relatives living today. All are herbivorous, browsing on a diet of leaves and young shoots. Oreodonts fed on different types of vegetation than many modern artiodactyls do and therefore occupied an ecologically different niche than many living ungulates. Found only in North America, oreodonts would eventually rival the large and diverse extant populations of modern bovid artiodactyls in Africa (antelopes, wildebeest, and buffalo) or the equally diverse populations of deer and goats of Asia. Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Artiodactyla Family: †Merycoidodontidae