The Cenozoic is Earth's current geological era, representing the last 66 million years of Earth's history. It is characterized by the dominance of mammals, birds and flowering plants, a cooling and drying climate, and the current configuration of continents. It is the latest of three geological eras since complex life evolved, preceded by the Mesozoic and Paleozoic. It started with the Cretaceous–Paleogene extinction event, when many species, including the non-avian dinosaurs, became extinct in an event attributed by most experts to the impact of a large asteroid or other celestial body, the Chicxulub impactor.
The Miocene is the first geological epoch of the Neogene Period and extends from about 23.03 to 5.333 million years ago (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words μείων and καινός and means "less recent" because it has 18% fewer modern marine invertebrates than the Pliocene has. The Miocene is preceded by the Oligocene and is followed by the Pliocene.
The Neogene, informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago (Mya) to the beginning of the present Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868).
Struthioniformes is an order of birds with only a single extant family, Struthionidae, containing the ostriches. Several other extinct families are known, spanning across the Northern Hemisphere, from the Early Eocene to the early Pliocene, including a variety of flightless forms like the Paleotididae, Geranoididae, Eogruidae and Ergilornithidae, the latter two thought to be closely related to Struthionidae.
Amphisbaenia is a group of usually legless squamates, comprising over 200 extant species. Amphisbaenians are characterized by their long bodies, the reduction or loss of the limbs, and rudimentary eyes. As many species have a pink body and scales arranged in rings, they have a superficial resemblance to earthworms. While the genus Bipes retains forelimbs, all other genera are limbless. Although superficially similar to the snakes and blind lizards, recent phylogenetic studies suggest that they are most closely related to wall lizards of the family Lacertidae. Amphisbaenians are widely distributed, occurring in North America, Europe, Africa, South America, Western Asia and the Caribbean. Most species are less than 6 inches (150 mm) long.
Carettochelyidae is a family of cryptodiran turtles belonging to the Trionychia. It contains only a single living species, the pig-nosed turtle native to New Guinea and Northern Australia. Stem-group carettochelyids are known from the Cretaceous of Asia, with the family being widely distributed across North America, Europe and Asia during the Paleogene.
Phorusrhacids, colloquially known as terror birds, were an extinct clade of large carnivorous flightless birds that were one of the largest species of apex predators in South America during the Cenozoic era; their conventionally accepted temporal range covers from 62 to 1.8 million years (Ma) ago.
Chalicotheres are an extinct clade of herbivorous, odd-toed ungulate (perissodactyl) mammals that lived in North America, Eurasia, and Africa from the Middle Eocene until the Early Pleistocene, existing from 46.2 mya to 781,000 years ago. They are one of the five major radiations of perissodactyls, with three groups living, and two extinct.
Peltosaurus is an extinct genus of anguid lizard from North America that lived from the Eocene to the Oligocene. Peltosaurus belongs to the anguid subfamily Glyptosaurinae. The type species Peltosaurus granulosus was named in 1873 by American paleontologist Edward Drinker Cope. Many additional species have been named, but most have been reassigned to different genera. For example, Peltosaurus piger, named in 1928, was reclassified as Odaxosaurus piger, and P. jepseni, named in 1942 from the Paleocene of Wyoming, but was later reclassified as Proxestops jepseni. In 1955 a new species, Peltosaurus macrodon, was named from the Eocene of California. Lizard bones from the Late Miocene of Nebraska were attributed to a new species of Peltosaurus called P. minimus in 1976, extending the fossil range of Peltosaurus and Glyptosaurinae into the Neogene. However, these bones were later referred to a genus of skinks called Eumeces, meaning that the fossil range of Peltosaurus and Glyptosaurinae does not go beyond the Paleogene.
The Pelagornithidae, commonly called pelagornithids, pseudodontorns, bony-toothed birds, false-toothed birds or pseudotooth birds, are a prehistoric family of large seabirds. Their fossil remains have been found all over the world in rocks dating between the Early Paleocene and the Pliocene-Pleistocene boundary.
Madtsoiidae is an extinct family of mostly Gondwanan snakes with a fossil record extending from early Cenomanian to late Pleistocene strata located in South America, Africa, India, Australia and Southern Europe. Madtsoiidae include very primitive snakes, which like extant boas and pythons would likely dispatch their prey by constriction. Genera include Gigantophis, one of the longest snakes known, at an estimated 10.7 metres (35 ft), and the Australian Wonambi and Yurlunggur. As a grouping of basal forms the composition and even the validity of Madtsoiidae is in a state of flux as new pertinent finds are described.
Rhineuridae is a family of amphisbaenians that includes one living genus and species, Rhineura floridana, as well as many extinct species belonging to both Rhineura and several extinct genera. The living R. floridana is found only in Georgia and Florida, but extinct species ranged across North America, some occurring as far west as Oregon. The family has a fossil record stretching back 60 million years to the Paleocene and was most diverse in the continental interior during the Eocene and Oligocene.
Lazarussuchus is an extinct genus of amphibious reptile, known from the Cenozoic of Europe. It is the youngest known member of Choristodera, an extinct order of aquatic reptiles that first appeared in the Middle Jurassic. Fossils have been found in Late Paleocene, Late Oligocene, Early Miocene and Late Miocene deposits in France, Germany, and the Czech Republic. Two species have been named: the type species L. inexpectatus ("unexpected") from the late Oligocene of France. and L. dvoraki from the early Miocene of the Czech Republic. It was not a large animal; the skull of L. inexpectatus was only about 4.53 centimeters long (1.78 in), with the total preserved body and tail length being just over 30 centimetres. A complete specimen of Lazarussuchus with preserved soft tissue was found from the Late Paleocene of France, but has not been assigned to a species.
Pseudodontornis is a rather disputed genus of the prehistoric pseudotooth birds. The pseudotooth birds or pelagornithids were probably rather close relatives of either pelicans and storks, or of waterfowl, and are here placed in the order Odontopterygiformes to account for this uncertainty. Up to five species are commonly recognized in this genus.
Orthogenysuchus is an extinct genus of caimanine alligatorids. Fossils have been found from the Wasatch Beds of the Willwood Formation of Wyoming, deposited during the early Eocene. The type species is O. olseni. The holotype, known as AMNH 5178, is the only known specimen belonging to the genus and consists of a skull lacking the lower jaws. The braincase is filled in by the matrix and most of the suture lines between bones are indiscernible, making comparisons with other eusuchian material difficult.
Sebecus is an extinct genus of sebecid crocodylomorph from Eocene of South America. Like other sebecosuchians, it was entirely terrestrial and carnivorous. The genus is currently represented by two species, the type S. icaeorhinus and S. ayrampu. Several other species have been referred to Sebecus, but were later reclassified as their own genera.
Dyticonastis is an extinct genus of amphisbaenians, or worm lizards, that includes a single species, Dyticonastis rensbergeri, that lived during the late Oligocene and early Miocene in what is now Oregon. Fossils of the species come from the John Day Formation. It belongs to Rhineuridae, a family that includes many other extinct North American amphisbaenians but only one living species, Rhineura floridana, from Florida. Dyticonastis rensbergeri occurs the farthest west of all rhineurid species. Like all rhineurids, Dyticonastis has a shovel-like snout adapted for burrowing underground, but it differs from most other members of the group in having a relatively shallow angle to its snout wedge and in having a widened snout tip. The only other rhineurids that share these features are species of the genus Spathorhynchus, which lived from the Middle Eocene to the Early Oligocene in what is now Wyoming. A 2007, phylogenetic analysis of amphisbaenians found that Dyticonastis and Spathorhynchus are each other's closest relatives, suggesting that both taxa may have evolved through vicariant speciation; the growth of the Rocky Mountains during the earliest stages of the Laramide orogeny in the early Paleogene would have separated North American rhineurids into eastern and western populations, with the western population producing Dyticonastis and Spathorhynchus.
Spathorhynchus is an extinct genus of amphisbaenians or worm lizards that existed from the Middle Eocene to the Early Oligocene in what is now Wyoming. It includes two species, the type species S. fossorium, named in 1973 from the Middle Eocene Bridger and Wind River Formations, and the species S. natronicus, named in 1977 from the Lower Oligocene White River Formation. Spathorhynchus belongs to the family Rhineuridae, which includes many other extinct species that ranged across North America at various times in the Cenozoic but only has one surviving member, Rhineura floridana, from Florida. Spathorhynchus differs from all other rhineurids except Dyticonastis from the Late Oligocene-Early Miocene of Oregon in having a slightly widened, spatula-shaped snout tip with a low angle of about 30 degrees. The two taxa may be closely related, having evolved in isolation in western North America after the formation of the Rocky Mountains separated them from rhineurids further east.
Ototriton is an extinct genus of rhineurid amphisbaenian or worm lizard from the Early Eocene of the western United States, including the type and only species Ototriton solidus. Paleontologist F. B. Loomis named Ototriton in 1919 on the basis of a single skull from the Wind River Formation in Wyoming, misinterpreting it as the skull of a salamander. Unlike salamanders and like other rhineurids, Ototriton has a shovel-shaped snout that it presumably used for burrowing underground. Ototriton is one of the earliest known rhineurids and also one of the largest.
Hyaenodonta is an extinct order of hypercarnivorous placental mammals from clade Ferae. Hyaenodonts were important mammalian predators that arose during the early Paleocene in Europe and persisted well into the late Miocene.
