The Oligocene is a geologic epoch of the Paleogene Period and 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 the Ancient Greek ὀλίγος and καινός, 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.
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.
The family Gryllidae contains the subfamilies and genera which entomologists now term true crickets. Having long, whip-like antennae, they belong to the Orthopteran suborder Ensifera, which has been greatly reduced in the last 100 years : taxa such as the spider-crickets and allies, sword-tail crickets, wood or ground crickets and scaly crickets have been elevated to family level. The type genus is Gryllus and the first use of the family name "Gryllidae" was by Francis Walker.
Cynodictis is an extinct amphicyonid carnivoran which inhabited Eurasia from the Late Eocene subepoch to the Early Oligocene subepoch living from 37.2 to 28.4 million years ago, existing for approximately 8.8 million years.
Hyaenodon ("hyena-tooth") is an extinct genus of carnivorous placental mammals from extinct tribe Hyaenodontini within extinct subfamily Hyaenodontinae, that lived in Eurasia and North America from the middle Eocene, throughout the Oligocene, to the early Miocene.
Presbyornis is an extinct genus of anseriform bird. It contains two unequivocally accepted species; the well-known P. pervetus and the much lesser-known P. isoni. P. pervetus was approximately the size and shape of a goose, but with longer legs; P. isoni, known from a few bones, was much larger, more than swan-sized. Other fossils, more doubtfully assigned to this genus, are also known.
Copromorphidae, the "tropical fruitworm moths", is a family of insects in the lepidopteran order. These moths have broad, rounded forewings, and well-camouflaged scale patterns. Unlike Carposinidae the mouthparts include "labial palps" with the second rather than third segment the longest. With other unusual structural characteristics of the caterpillar and adult, it could represent the sister lineage of all other extant members of this superfamily. The genus Sisyroxena from Madagascar is also notable for its unusual venation and wing scale sockets.
Palaeotheriidae is an extinct family of herbivorous perissodactyl mammals that inhabited Europe, with less abundant remains also known from Asia, from the mid-Eocene to the early Oligocene. They are classified in Equoidea, along with the living family Equidae.
The Hampshire Basin is a geological basin of Palaeogene age in southern England, underlying parts of Hampshire, the Isle of Wight, Dorset, and Sussex. Like the London Basin to the northeast, it is filled with sands and clays of Paleocene and younger ages and it is surrounded by a broken rim of chalk hills of Cretaceous age.
Anosteira is an extinct genus of carettochelyid turtle from the Eocene to the Oligocene of Asia and North America.
Sisyridae, commonly known as spongeflies or spongillaflies, are a family of winged insects in the order Neuroptera. There are approximately 60 living species described, and several extinct species identified from the fossil record.
Whitecliff Bay and Bembridge Ledges is a 131.6-hectare (325-acre) Site of Special Scientific Interest that lies around the coastline of the easternmost part of the Isle of Wight from the Bembridge harbour entrance in the north around Foreland to Whitecliff Bay to the south. The site was notified in 1955 for both its biological and geological features.
Allaeochelys is an extinct genus of Carettochelyid turtle, known from the Eocene to Miocene of Europe, Asia, North America and Africa.
The Bouldnor Formation is a geological formation in the Hampshire Basin of southern England. It is the youngest formation of the Solent Group and was deposited during the uppermost Eocene and lower Oligocene.
Mastotermes is a genus of termites. The sole living species is Mastotermes darwiniensis, found only in northern Australia. A number of extinct taxa are known from fossils. It is a very peculiar insect, the most primitive termite alive. As such, it shows notable similarities to cockroaches in the family Cryptocercidae, the termites' closest relatives. These similarities include the anal lobe of the wing and the laying of eggs in bunches, rather than singly. The termites were traditionally placed in the Exopterygota, but such an indiscriminate treatment makes that group a paraphyletic grade of basal neopterans. Thus, the cockroaches, termites and their relatives are nowadays placed in a clade called Dictyoptera.
The geology of the Isle of Wight is dominated by sedimentary rocks of Cretaceous and Paleogene age. This sequence was affected by the late stages of the Alpine Orogeny, forming the Isle of Wight monocline, the cause of the steeply-dipping outcrops of the Chalk Group and overlying Paleogene strata seen at The Needles, Alum Bay and Whitecliff Bay.
The Solent Group is a geological group in the Hampshire Basin of southern England. It preserves fossils ranging in age from Priabonian to Rupelian. The group is subdivided into three formations, the Headon Hill Formation, the Bembridge Limestone Formation and the Bouldnor Formation.
Emplastus is an extinct morphogenus of ants in the subfamily Dolichoderinae, known from fossils found in Asia and Europe. The genus contains twelve species described from sites in England, Eastern Europe and Far Eastern Russia.
Oligobombus is an extinct genus of bumblebee relatives in the tribe Bombini, containing the single species Oligobombus cuspidatus. The genus and species were described by Antropov (2014) based on a single fore-wing from the Late Eocene Bembridge Marls Insect Bed on the Isle of Wight, England. The fossil was described by re-examining a specimen in the Smith Collection. The collection was originally made by A'Court Smith, and purchased by the Natural History Museum in 1877 and 1883.
Phocavis is an extinct genus of flightless seabird, belonging to the family Plotopteridae, and distantly related with modern cormorants. Its fossils, found in the Keasey Formation in Oregon, are dated from the Late Eocene.
