Phylum | Class | Order | Family | Chordata | Reptilia | Ornithischia | Pachycephalosauridae | Age | Geologic time | 75 - 66 Ma | | Cretaceous | | Pachycephalosaurus wyomingensis | Phylum | Class | Order | Family | Chordata | Reptilia | Ornithischia | Pachycephalosauridae | Age | Geologic time | 75 - 66 Ma | | Cretaceous | |
PachycephalosaurusThe bone-headed dinosaur lived in Cretaceous Period of North America. The plants in this environment were not too different from what we see today, including familiar flowering plants such as Magnolia. |
Phylum | Class | Order | Family | Chordata | Reptilia | Ornithischia | Ceratopsidae | Age | Geologic time | 73.5 - 69 Ma | | Cretaceous | |
Pachyrhinosaurus canadensisUnlike its better-known cousin Triceratops, Pachyrhinosaurus had no horns on its face. The lumpy mass of bone, called a nasal boss, was likely used for combat with its own species. | Phylum | Class | Order | Family | Chordata | Mammalia | Artiodactyla | Pakicetidae | Age | Geologic time | 52 - 48 Ma | | Paleogene | |
PakicetusIt lived roughly 50 million years ago and is widely regarded as the earliest known whale. With its four long legs, it was more similar in appearance to its even-toed ungulate relatives, like pigs and the hippopotamus. |
|
|
Phylum | Class | Order | Family | Chordata | Mammalia | Rodentia | Castoridae | Age | Geologic time | | | Paleogene | Neogene | |
Palaeocastor“Devil’s Corkscrew” is the name given to the fossilized burrows dug by the extinct beaver Palaeocastor. The strangely-shaped burrows were previously believed to be freshwater sponges or some kind of vegetation. | Phylum | Class | Order | Family | Chordata | Mammalia | Carnivoria | Felidae | Age | Geologic time | 1.3 Ma - 11,000 | | Quaternary | |
Panthera leo spelaeaWhile many cave lion fossils have been found in caves, this extinct big cat actually lived in various ecosystems from Spain to Alaska. Prehistoric paintings and figurines made by ice age societies help us understand what the cats would've looked like in life. |
Phylum | Class | Order | Family | Mollusca | Cephalopoda | Ammonitida | Desmoceratidae | Age | Geologic time | 94 - 72 Ma | | Cretaceous | |
ParapuzosiaParapuzosia was a large Cretaceous ammonite which could grow up to 3 m (9.8 ft) in diameter. It lived in a sea full of predators like the monitor lizard-like Mosasaurus. | Phylum | Class | Order | Family | Chordata | Reptilia | Ornithischia | Hadrosauridae | Age | Geologic time | 76 - 65 Ma | | Cretaceous | | Parasaurolophus |
Phylum | Class | Order | Family | Chordata | Mammalia | Rodentia | Dinomyidae | Age | Geologic time | | | Neogene | |
PhoberomysAs a giant caiman, Purussaurus grew up to 12.5 m (41 ft) long and had twice the bite force of Tyrannosaurus. In life, it could have preyed on large animals such as the rhinoceros-sized rodent Phoberomys. | Phylum | Class | Order | Family | Chordata | Reptilia | Phytosauria | Phytosauridae | Age | Geologic time | 245 - 199.6 Ma | | Triassic | |
PhytosauridaePhytosaurs are an extinct group of large, mostly semiaquatic Late Triassic archosauriform reptiles. Phytosaurs were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodilians in size, appearance, and lifestyle, as an example of convergence or parallel evolution. |
Phylum | Class | Order | Family | Chordata | Mammalia | Proboscidea | Amebelodontidae | Age | Geologic time | 15 - 10 Ma | | Neogene | |
Platybelodon grangeriPlatybelodon, or "Flat-spear tusk", was an elephant relative from the Miocene Epoch. Despite its shovel-like appearance, its jaw was likely used to cut vegetation like a scythe. | Phylum | Class | Order | Family | Chordata | Mammalia | Proboscidea | Amebelodontidae | Age | Geologic time | 15 - 4 Mo | | Neogene | | Platybelodon holyokensis |
Phylum | Class | Order | Family | Chordata | Reptilia | Plesiosauria | | Age | Geologic time | 203.6 - 66 Ma | | Jurassic | Cretaceous | |
PlesiosauriaPlesiosaurs had a broad flat body and a short tail. Their limbs had evolved into four long flippers, which were powered by strong muscles attached to wide bony plates formed by the shoulder girdle and the pelvis. The flippers made a flying movement through the water. Plesiosaurs breathed air, and bore live young; there are indications that they were warm-blooded. | Phylum | Class | Order | Family | Chordata | Reptilia | Rauisuchia | Rauisuchidae | Age | Geologic time | 220 - 215 Ma | | Triassic | | Postosuchus kirkpatricki |
Phylum | Class | Order | Family | Chordata | Reptilia | Ornithischia | Pachycephalosauridae | Age | Geologic time | 80 - 75 Ma | | Cretaceous | |
Prenocephale prenesThis Late Cretaceous dinosaur is related to the better known dome-headed dinosaur, Pachycephalosaurus. Its thick dome is decorated with spikes and bumps, and was likely used in combat. | Phylum | Class | Order | Family | Chordata | Amphibia | Anura | Pelobatoidea | Age | Geologic time | +/- 60 Ma | | Paleogene | |
Prospea holoseriscaCrown-group spadefoot toads (Anura: Pelobatoidea) are the best-known fossorial frog clade to inhabit arid environments, with species utilizing a characteristic bony spade on their foot for burrowing. Here we report a rare fossil of a crown-group spadefoot toad from the late Paleocene of Mongolia. The late Paleocene age and other information suggestive of a mild climate cast doubt on the conventional assertion that burrowing evolved as an adaptation to aridity in spadefoot toads. Quantitative biogeographic analysis suggests that Scaphiopodidae, despite originating in North America, dispersed into East Asia via Beringia in the Early Cenozoic. |
Phylum | Class | Order | Family | Chordata | Reptilia | Ornithischia | Protoceratopsidae | Age | Geologic time | 85 - 75 Ma | | Cretaceous | | Protoceratops andrewsi | Psittacosaurus mongolensis |
Phylum | Class | Order | Family | Chordata | Reptilia | Pterosauria | Pteranodontidae | Age | Geologic time | 115 - 70 Ma | | Cretaceous | | Pteranodon sternbergi | Phylum | Class | Order | Family | Chordata | Reptilia | Pterosauria | Pteranodontidae | Age | Geologic time | 115 - 70 Ma | | Cretaceous | |
PteranodonWith over 1,200 specimens found, the fish-eating Pteranodon is the best understood pterosaur genus. It lived by the ancient sea that once divided North America and could have shared this habitat with the aquatic bird Hesperornis. |
Phylum | Class | Order | Family | Chordata | Reptilia | Pterosauria | Ctenochasmatidae | Age | Geologic time | 145 - 100 Ma | | Cretaceous | | Pterodaustro guinazui | Phylum | Class | Order | Family | Chordata | Reptilia | Saurischia | ? | Age | Geologic time | | | Jurassic | |
Pulanesaura eocollumUnlike its later relatives which fed on taller trees, this Early Jurassic sauropod was a low browser. Its name comes from the Sesotho word meaning "comes with rain", referring to the rain that poured during its excavation. |
Phylum | Class | Order | Family | Chordata | Reptilia | Crocodilia | Alligatoridae | Age | Geologic time | | | Neogene | |
PurussaurusAs a giant caiman, Purussaurus grew up to 12.5 m (41 ft) long and had twice the bite force of Tyrannosaurus. In life, it could have preyed on large animals such as the rhinoceros-sized rodent Phoberomys. | Phylum | Class | Order | Family | Chordata | Reptilia | Saurischia | Abelisauridae | Age | Geologic time | 70 a | | Cretaceous | |
PycnonemosaurusPycnomemosaurus and Carnotaurus were South American abelisaurids. These strange Cretaceous theropods with vestigial arms, powerful legs and ornamented heads were the apex predators in their ecosystems. |