Archegosaurus is a genus of amphibian which lived during the Asselian to Wuchiapingian ages of the Permian, around 299-253 million years ago.

Archegosaurus Head

Archegosaurus is a genus of amphibian which lived during the Asselian to Wuchiapingian ages of the Permian,…

Archegosaurus is a genus of amphibian which lived during the Asselian to Wuchiapingian ages of the Permian, around 299-253 million years ago. Pictured here is the dorsal vertebrae.

Dorsal Vertebrae of the Archegosaurus

Archegosaurus is a genus of amphibian which lived during the Asselian to Wuchiapingian ages of the Permian,…

Branchiosaurus (Greek for "gill lizard") is a genus of small, lightly-built early prehistoric amphibians. Pictured here is the dorsal vertebra.

Dorsal Vertebra of Branchiosaurus

Branchiosaurus (Greek for "gill lizard") is a genus of small, lightly-built early prehistoric amphibians.…

This illustration shows the track of a Brontozoum Giganteum. The trac is actually eighteen inches long, with the dinosaur standing over twenty feet high.

Brontozoum Giganteum

This illustration shows the track of a Brontozoum Giganteum. The trac is actually eighteen inches long,…

Tracks of Chirotherium or "hand-beast" in Buntsandstein found in Hessbeg, Germany.

Chirotherium Tracks

Tracks of Chirotherium or "hand-beast" in Buntsandstein found in Hessbeg, Germany.

An illustration of a Diplodocus skeleton and the caudal vertebrae (A and B). Diplodocus is a genus of diplodocid sauropod dinosaur whose fossils were first discovered in 1877 by S. W. Williston. It lived in what is now western North America at the end of the Jurassic Period. Diplodocus is one of the more common dinosaur fossils found in the Upper Morrison Formation, a sequence of shallow marine and alluvial sediments deposited about 150 to 147 million years ago, in what is now termed the Kimmeridgian and Tithonian stages.

Diplodocus

An illustration of a Diplodocus skeleton and the caudal vertebrae (A and B). Diplodocus is a genus of…

The skeleton of an elasmosaurus, a dinosaur in the order of plesiosaurs.

Elasmosaurus Skeleton

The skeleton of an elasmosaurus, a dinosaur in the order of plesiosaurs.

Found in Oueensland and other parts of Australia, this lizard belongs to the family Agamidae. It reaches a length of about thirty-two inches, and receives its name from the presence of a large expansion of skin at either side of the neck. This frill is notched at the edge, has special supporting cartilages, and by means of muscles can be folded or expanded at will. The lizard walks upon its hind limbs, like the extinct Iguanodon, having the fore limbs hanging down. When at bay, it expands the frill to its fullest extent and opens the mouth wide, exposing its teeth. It inhabits sandy districts.

Frilled Lizard

Found in Oueensland and other parts of Australia, this lizard belongs to the family Agamidae. It reaches…

"Glyptodon (Glyptodon clavipes). The typical and best-known genus of the family Glyptodontidae; the long-tailed fossil armadillos or glyptodons, with 5 toes on the hind feet and 4 on the fore, the fifth digit of which is wanting." -Whitney, 1911

Glyptodon

"Glyptodon (Glyptodon clavipes). The typical and best-known genus of the family Glyptodontidae; the…

The hylaeosaurus measured between twenty and thirty feet in length, and fed on vegetation.

Hylaeosaurus

The hylaeosaurus measured between twenty and thirty feet in length, and fed on vegetation.

Hylonomus was an early reptile. It lived 315 Ma (million years ago) during the Carboniferous period. Pictured here is the dorsal vertebra

Dorsal Vertebra of the Hylonomus

Hylonomus was an early reptile. It lived 315 Ma (million years ago) during the Carboniferous period.…

African dwarf frogs of genus Hymenochirus, also known as dwarf aquatic frogs, are frogs native to Sub Saharan Africa. Pictured here in the vertebral column.

Vertebral Column of Hymenochirus

African dwarf frogs of genus Hymenochirus, also known as dwarf aquatic frogs, are frogs native to Sub…

An illustration of an Ichthyosaurus skeleton. Ichthyosaurus is an extinct genus of ichthyosaur from the Early Jurassic (Hettangian - Sinemurian) of Europe (Belgium, England and Germany). It is among the best known ichthyosaur genera, with the Order Ichthyosauria being named after it. Ichthyosaurus was the first complete fossil to be discovered in the early 1800's by Mary Anning in England.

Archaeopteryx Skeleton

An illustration of an Ichthyosaurus skeleton. Ichthyosaurus is an extinct genus of ichthyosaur from…

An illustration of an Ichthyosaurus skull. Ichthyosaurus is an extinct genus of ichthyosaur from the Early Jurassic (Hettangian - Sinemurian) of Europe (Belgium, England and Germany). It is among the best known ichthyosaur genera, with the Order Ichthyosauria being named after it. Ichthyosaurus was the first complete fossil to be discovered in the early 1800's by Mary Anning in England.

Ichthyosaurus Skull

An illustration of an Ichthyosaurus skull. Ichthyosaurus is an extinct genus of ichthyosaur from the…

The full-grown iguanodon is estimated to have reached lengths of thirty feet.

Iguanadon

The full-grown iguanodon is estimated to have reached lengths of thirty feet.

Some Late Mesozoic reptiles. Shown are the Tyrannosaurus, Trachodon, Triceratops, Pterodactyls, and the Archaeopteryx. The six-foot man is drawn to the same scale as the other animals.

Late Mesozoic Age Reptiles

Some Late Mesozoic reptiles. Shown are the Tyrannosaurus, Trachodon, Triceratops, Pterodactyls, and…

"Megalosaurus—a great terrestrial reptile." -Taylor, 1904

Megalosaurus

"Megalosaurus—a great terrestrial reptile." -Taylor, 1904

A pair of megalosauruses, with a group of pterodactyls in the background.

Megalosaurus and pterodactyls

A pair of megalosauruses, with a group of pterodactyls in the background.

Megatherium ("Great Beast") was a genus of elephant-sized ground sloths that lived from two million to 8,000 years ago. A related genus was Nothrotheriops, which were primarily bear-sized ground sloths. The rhinoceros-sized Promegatherium is suggested to be the ancestor of Megatherium.

Megatherium Skeleton

Megatherium ("Great Beast") was a genus of elephant-sized ground sloths that lived from two million…

Some Mesozoic reptiles. Shown are the Brontosaurus, Stegosaurus, Pterodactyl, Camptosaurus, and the Diplodocus. The six-foot man is drawn to the same scale as the other animals.

Mesozoic Age Reptiles

Some Mesozoic reptiles. Shown are the Brontosaurus, Stegosaurus, Pterodactyl, Camptosaurus, and the…

A remarkable genus of fossil lizards, peculiar to the Mesozoic strata. Its anomalous structure was long a puzzle to comparative anatomists.

Pterodactyl

A remarkable genus of fossil lizards, peculiar to the Mesozoic strata. Its anomalous structure was long…

A remarkable genus of fossil lizards, peculiar to the Mesozoic strata. Its anomalous structure was long a puzzle to comparative anatomists.

Pterodactyl

A remarkable genus of fossil lizards, peculiar to the Mesozoic strata. Its anomalous structure was long…

"A genus of extinct flying reptiles of the order Pterosauria, found in the Jura Limestone formation, in the Lias at Lyme-Regis, in the Oolite slate of Stonefield." -Marshall

Pterodactyl

"A genus of extinct flying reptiles of the order Pterosauria, found in the Jura Limestone formation,…

"So peculiar and strange is the structure of these animals, that the first specimen discovered was classed by one naturalist as a bird, by another as a species of bat, and by yet a third as a flying reptile." — Goodrich, 1844

Pterodactyle skeleton

"So peculiar and strange is the structure of these animals, that the first specimen discovered was classed…

A large reptile sunning itself on a rocky island.

Reptile

A large reptile sunning itself on a rocky island.

An illustration of the skull of a megalosaurus. Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period (Bathonian) of Europe (Southern England, France, Portugal). It is significant as the first genus of dinosaur (outside of birds) to be described and named.

Megalosaurus Skull

An illustration of the skull of a megalosaurus. Megalosaurus is a genus of large meat-eating theropod…