Famennian
Encyclopedia
The Famennian is one of two faunal stage
s in the Late Devonian epoch. It lasted from 374.5 ± 2.6 million years ago to 359.2 ± 2.5 million years ago. It was preceded by the Frasnian
stage and followed by the Tournaisian
stage and is named after Famenne
, a natural region in southern Belgium.
It was during this age that tetrapod
s first appeared. In the seas, a novel major group of ammonoid cephalopod
s called clymeniids appeared, underwent tremendous diversification
and spread worldwide, then just as suddenly went extinct.
The beginning of the Famennian is marked by a major extinction event
, and the end with a smaller but still quite severe extinction event.
North American subdivisions of the Famennian include the Chautauquan, Canadaway, Conneaut, Conneautan, Conewango and Conewangan.
Faunal stage
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries.Rock...
s in the Late Devonian epoch. It lasted from 374.5 ± 2.6 million years ago to 359.2 ± 2.5 million years ago. It was preceded by the Frasnian
Frasnian
The Frasnian is one of two faunal stages in the Late Devonian epoch. It lasted from 385.3 ± 2.6 million years ago to 374.5 ± 2.6 million years ago. It was preceded by the Givetian stage and followed by the Famennian stage...
stage and followed by the Tournaisian
Tournaisian
The Tournaisian is in the ICS geologic timescale the lowest stage or oldest age of the Mississippian, the oldest subsystem of the Carboniferous. The Tournaisian age lasted from 359.2 ± 2.5 Ma to 345.3 ± 2.1 Ma...
stage and is named after Famenne
Famenne
Famenne is a natural region in southern Belgium. Together with The Fagne or la Fagne, west of the river Meuse, it is part of the Fagne-Famenne natural region...
, a natural region in southern Belgium.
It was during this age that tetrapod
Tetrapod
Tetrapods are vertebrate animals having four limbs. Amphibians, reptiles, birds and mammals are all tetrapods; even snakes and other limbless reptiles and amphibians are tetrapods by descent. The earliest tetrapods evolved from the lobe-finned fishes in the Devonian...
s first appeared. In the seas, a novel major group of ammonoid cephalopod
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s called clymeniids appeared, underwent tremendous diversification
Biodiversity
Biodiversity is the degree of variation of life forms within a given ecosystem, biome, or an entire planet. Biodiversity is a measure of the health of ecosystems. Biodiversity is in part a function of climate. In terrestrial habitats, tropical regions are typically rich whereas polar regions...
and spread worldwide, then just as suddenly went extinct.
The beginning of the Famennian is marked by a major extinction event
Late Devonian extinction
The Late Devonian extinction was one of five major extinction events in the history of the Earth's biota. A major extinction, the Kellwasser Event, occurred at the boundary that marks the beginning of the last phase of the Devonian period, the Famennian faunal stage, , about 374 million years ago...
, and the end with a smaller but still quite severe extinction event.
North American subdivisions of the Famennian include the Chautauquan, Canadaway, Conneaut, Conneautan, Conewango and Conewangan.
Fauna
- Fish
- CabonnichthysCabonnichthysCabonnichthys is an extinct genus of Tristichopterid fish that lived in the Late Devonian period of Australia....
- MandageriaMandageriaMandageria is an extinct genus of lobe-finned fish. Mandageria lived in the Late Devonian period...
- Cabonnichthys
- Tetrapods
- AcanthostegaAcanthostegaAcanthostega is an extinct labyrinthodont genus, among the first vertebrate animals to have recognizable limbs. It appeared in the Upper Devonian about 365 million years ago, and was anatomically intermediate between lobe-finned fishes and the first tetrapods fully capable of coming onto...
- ElginerpetonElginerpetonElginerpeton is a monotypic genus of early tetrapod, the fossils of which were recovered from Scat Craig, Scotland, in rocks dating to the late Devonian Period...
- IchthyostegaIchthyostegaIchthyostega is an early tetrapod genus that lived at the end of the Upper Devonian period . It was a labyrinthodont, one of the first fossil record of tetrapods. Ichthyostega possessed lungs and limbs that helped it navigate through shallow water in swamps...
- VentastegaVentastegaVentastega was a basal tetrapod that lived during the Famennian subdivision of the Late Devonian period approximately 374.5 to 359.2 million years ago, though Ventastega origins as a tetrapod lineage are probably seated in the preceding Frasnian period of the Late Devonian when a surge of...
- Acanthostega