Geologic Time Scale: Oligocene Epoch
(33.9 to 23 million years ago)
The Oligocene Epoch follows the Eocene Epoch and is followed by the Miocene Epoch of the Cenozoic Era. 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 meaning “few” and “new”/”recent”, and refers to the sparsity of extant forms of mollusca.
The Oligocene is often considered an important time of transition, a link between the archaic world of the tropical Eocene and the morn modern ecosystems of the Miocene. Major changes during the Oligocene included a global expansion of grasslands, and a regression of tropical broad leaf forest to the equatorial belt.
Chattian Age/Stage
27.82 to 23.03 million years ago
The Chattian Stage was named after the Chatti, a Germanic tribe by Austrian paleontologist Theodor Fuchs in 1894.
North American Chattian Stage 27.82 to 23.03 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
European Chattian Stage 27.82 to 23.03 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
African Chattian Stage 27.82 to 23.03 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
Asian Chattian Stage 27.82 to 23.03 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
Genus: Paraceratherium ‘Near horn beast”
Diet: Herbivore
Size: 4.8 meters high at the shoulder
Known locations: China, India, Kazakhstan, and Pakistan
Time period: Oligocene (Rupelian to Chattian)
Size: 4.8 meters high at the shoulder
Diet: Herbivore
Rupelian Age/Stage
33.9 to 27.82 million years ago
The Rupelian Stage was named after the small river Rupen in Belgium, a tributary to the Scheldt by Belgian geologist Andre Hubert Dumont in 1850.
North American Rupelian Stage 33.9 to 27.82 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
Genus: Megacerops “Large horned face”
Size: 2.5 meters tall at the shoulder
Locations: Canada, Seskatchewan. USA, Colorado, Montana, South Dakota, Wyoming
Time period: Eocene (Priabonian) to Oligocene (Rupelian)
Diet: Herbivore.
European Rupelian Stage 33.9 to 27.82 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
Genus and species: Eusmilus bidentatus
Common name: False Saber-toothed cat
Classification: Family: Nimravidae – Subfamily: Hoplophoninae
Time: Late Eocene to Early Oligocene
Range: Europe
Diet: Carnivore
Genus: Entelodon ”Perfect teeth”
Known locations: Eurasia
Time period: Bartonian of the Eocene through to Rupelian of the Oligocene
Size: Around 3 meters long
Diet: Omnivore?
Genus: Palaeotherium ”Ancient beast”
Known locations: Europe, France, Germany, Spain, Switzerland and the United Kingdom.
Time period: Eocene (Lutetian to Priabonian) and Oligocene (Rupelian )
Size: 120 centimeters long, 75 to 140 centimeters high at the shoulder
Diet: Herbivore
African Rupelian Stage 33.9 to 27.82 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
Genus: Arsinoitherium “Arsinoe’s beast, after Queen Arsinoe I of Ancient Egypt”
Time: Late Eocene to Early Oligocene 36-27 mya
Locations: Egypt - Jebel Qatrani Formation, Ethiopia, Oman - Aydim Formation, Saudi Arabia - Shumaysi Formation.
Size: 1.75m (5.7ft) hieght and 3m (9.8ft) length
Diet: Herbivore
Asian Rupelian Stage 33.9 to 27.82 million years ago
Genus and species: Hyaenodon horridus
Name meaning: Hyena-tooth
Common name: Hyaenodon
Classification: Order: Hyaenodonta – Family: Hyaenodontidae
Time: Middle Eocene to Middle Miocene
Range: Eurasia, Africa, and North America
Diet: Carnivore
Genus: Entelodon ”Perfect teeth”
Known locations: Eurasia
Time period: Bartonian of the Eocene through to Rupelian of the Oligocene
Size: Around 3 meters long
Diet: Omnivore?
