The Eocene is a geological epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name Eocene comes from the Ancient Greek Ἠώς and καινός and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.
The Oligocene is a geologic epoch of the Paleogene Period that extends from about 33.9 million to 23 million years before the present. As with other older geologic periods, the rock beds that define the epoch are well identified but the exact dates of the start and end of the epoch are slightly uncertain. The name Oligocene was coined in 1854 by the German paleontologist Heinrich Ernst Beyrich from his studies of marine beds in Belgium and Germany. The name comes from Ancient Greek ὀλίγος (olígos) 'few' and καινός (kainós) 'new', and refers to the sparsity of extant forms of molluscs. The Oligocene is preceded by the Eocene Epoch and is followed by the Miocene Epoch. The Oligocene is the third and final epoch of the Paleogene Period.
Lampriformes is an order of ray-finned fish. Members are collectively called lamprids or lampriforms, and unite such open-ocean and partially deep-sea Teleostei as the crestfishes, oarfish, opahs, and ribbonfishes. A synonym for this order is Allotriognathi, while an often-seen, but apparently incorrect, spelling variant is Lampridiformes. They contain seven extant families which are generally small but highly distinct, and a mere 12 lampriform genera with some 20 species altogether are recognized. They are the only extant members of the superorder Lamprimorpha, which was formerly diverse throughout much of the Late Cretaceous.
The Lacertidae are the family of the wall lizards, true lizards, or sometimes simply lacertas, which are native to Afro-Eurasia. It is a diverse family with at about 360 species in 39 genera. They represent the dominant group of reptiles found in Europe.
Plotopteridae is an extinct family of flightless seabirds with uncertain placement, generally considered as member of order Suliformes. They exhibited remarkable convergent evolution with the penguins, particularly with the now extinct giant penguins. That they lived in the North Pacific, the other side of the world from the penguins, has led to them being described at times as the Northern Hemisphere's penguins, though they were not closely related. More recent studies have shown, however, that the shoulder-girdle, forelimb and sternum of plotopterids differ significantly from those of penguins, so comparisons in terms of function may not be entirely accurate. Plotopterids are regarded as closely related to Anhingidae (darters) and Phalacrocoracidae (cormorants). On the other hand, there is a theory that this group may have a common ancestor with penguins due to the similarity of forelimb and brain morphology. However, the endocast morphology of stem group Sphenisciformes differs from both Plotopteridae and modern penguins.
Archaeotrogonidae is a prehistoric bird family known from the Eocene and Oligocene of Europe. They are members of Strisores, and are thought to be closely related to nightjars.
Anosteira is an extinct genus of carettochelyid turtle from the Eocene to the Oligocene of Asia and North America.
Herpetotheriidae is an extinct family of metatherians, closely related to marsupials. Species of this family are generally reconstructed as terrestrial, and are considered morphologically similar to modern opossums. Fossils of herpetotheriids come from North America, Asia, Europe, Africa, and perhaps South America. The oldest representative is Maastrichtidelphys from the latest Cretaceous (Maastrichtian) of the Netherlands and the youngest member is Amphiperatherium from the Middle Miocene of Europe. The group has been suggested to be paraphyletic, with an analysis of petrosal anatomy finding that North American Herpetotherium was more closely related to marsupials than the European Peratherium and Amphiperatherium.
Miocyon is an extinct genus of placental mammals from clade Carnivoraformes, that lived in North America from the early to late Eocene.
Bajaichthys is an extinct Ypresian zeid from the Monte Bolca Lagerstätten of Italy. It contains a single species, B. elegans, and is the only member of the family Bajaichthyidae.
Turkmenidae is an extinct family of lamprids from the Paleogene of the west-central Asia, in what was formerly the Peri-Tethys Ocean. They were small, disk-shaped fish that bore a strong resemblance to their closest living relatives, the opahs.
Aglyptorhynchus is an extinct genus of prehistoric marine billfish that was distributed worldwide from the early Eocene to the early Miocene. Fossils are primarily known from the Northern Hemisphere, but one species is also known to have inhabited the waters off New Zealand.
Ampheristus is an extinct genus of prehistoric marine ray-finned fish. It was a basal or stem member of the family Ophidiidae, which contains modern cusk-eels. Fossils are known from worldwide from the Late Cretaceous to the late Paleogene, making it a rather successful survivor of the Cretaceous-Paleogene extinction event.
Dapalis is an extinct genus of prehistoric glassfish known from the Late Cretaceous to the Early Miocene. It is known from both freshwater and marine habitats of India, Australia, New Zealand, and much of mainland Europe.
Cylindracanthus is an extinct, enigmatic genus of marine ray-finned fish with fossils known throughout North America, Europe, Asia and Africa from the Late Cretaceous to the late Eocene, with potential Oligocene records and a possible Miocene record also known. It is exclusively known from its distinctive partial remains, which are long cylindrical bony spines that are usually considered rostrum fragments, as well as some associated teeth. These spines are abundant & widespread throughout this timespan, and are useful indicators of a nearshore marine environment, but the taxonomic identity of the fish is still highly uncertain and debated.
Palimphyes is an extinct genus of marine ray-finned fish known from the Paleogene period. It was a euzaphlegid, an extinct family of scombroid fish related to the escolars and snake mackerels.
Tomistominae is a subfamily of crocodylians that includes one living species, the false gharial. Many more extinct species are known, extending the range of the subfamily back to the Eocene epoch. In contrast to the false gharial, which is a freshwater species that lives only in southeast Asia, extinct tomistomines had a global distribution and lived in estuaries and along coastlines.
The Belgrade Formation is a limestone geologic formation in North Carolina characterized by limestone coquina mixed with sand, and thinly laminated clays. It preserves fossils dating back to the Paleogene period.
Termastherium is an extinct genus of leontiniid notoungulates that lived during the Early Oligocene of what is now Chile. Fossils of this genus have been found in the Oligocene-aged Abanico Formation of Chile.
Agnopterus is an extinct genus of stem-flamingo phoenicopteriform with fossil material from France, as well as possibly England, Kazakhstan, and Brazil. The holotype specimen for type species A. laurillardi is an incomplete distal tibiotarsus from Late Eocene gypsum from Paris; a coracoid, humeri, a scapula and perhaps a proximal femur have been recovered from Late Eocene to Early Oligocene of England to a possible second species, A. hantoniensis. Two additional species from the Late Oligocene-Early Miocene have been named as well. A. turgaiensis of Kazakhstan and A. sicki of Brazil. While all four species are considered to be close to the ancestry of flamingos, their exact relationships and placement as members of Agnopterus is uncertain.
