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Conodonts are an extinct group of agnathan (jawless) vertebrates resembling eels, classified in the class Conodonta. For many years, they were known only from their tooth-like oral elements, which are usually found in isolation and are now called conodont elements. Knowledge about soft tissues remains limited. They existed in the world's oceans for over 300 million years, from the Cambrian to the beginning of the Jurassic. Conodont elements are widely used as index fossils, fossils used to define and identify geological periods. The animals are also called Conodontophora to avoid ambiguity.
The Late Devonian extinction consisted of several extinction events in the Late Devonian Epoch, which collectively represent one of the five largest mass extinction events in the history of life on Earth. The term primarily refers to a major extinction, the Kellwasser event, also known as the Frasnian-Famennian extinction, which occurred around 372 million years ago, at the boundary between the Frasnian stage and the Famennian stage, the last stage in the Devonian Period. Overall, 19% of all families and 50% of all genera became extinct. A second mass extinction called the Hangenberg event, also known as the end-Devonian extinction, occurred 359 million years ago, bringing an end to the Famennian and Devonian, as the world transitioned into the Carboniferous Period.
The Famennian is the latter of two faunal stages in the Late Devonian Epoch. The most recent estimate for its duration estimates that it lasted from around 371.1 million years ago to 359.3 million years ago. An earlier 2012 estimate, still used by the International Commission on Stratigraphy, estimated that it lasted from 372.2 million years ago to 358.9 million years ago. It was preceded by the Frasnian stage and followed by the Tournaisian stage.
The Eifelian is the first of two faunal stages in the Middle Devonian Epoch. It lasted from 393.3 ± 1.2 million years ago to 387.7 ± 0.8 million years ago. It was preceded by the Emsian Stage and followed by the Givetian Stage.
The Pander Society is an informal organisation founded in 1967 for the promotion of the study of conodont palaeontology. It publishes an annual newsletter. Although there are regular meetings of the Pander Society, at the Annual Meeting of the Geological Society of America, at European Conodont Symposia, and elsewhere, any meeting of three or more "Panderers" is considered an official meeting of the "Pander Society". The society is headed by the Chief Panderer, currently Maria Cristina Perri of the Università di Bologna. The society confers two awards, the Pander Medal for a lifetime of achievement in conodont palaeontology, and the Hinde Medal for an outstanding contribution to conodont palaeontology by a young Panderer.
The Norway Point Formation is a geologic formation in Michigan. It preserves fossils dating back to the middle Devonian period.
The Thunder Bay Limestone is a geologic formation in Michigan. It preserves fossils dating back to the Devonian period.
The Alexo Formation a stratigraphic unit of Late Devonian age. It is present on the western edge of the Western Canada Sedimentary Basin in the central Rocky Mountains and foothills of Alberta. The formation consists primarily of dolomite. It is locally fossiliferous and includes remains of marine animals such as brachiopods and conodonts.
Palmatolepis is an extinct conodont genus in the family Palmatolepidae. It was the most abundant genus of conodonts of the Late Devonian, disappearing during the Devonian/Carboniferous crisis.
Acodus is an extinct genus of conodonts.
Zieglerodina is an extinct conodont genus in the family Spathognathodontidae.
Willi Ziegler was a German paleontologist.
Icriodus is an extinct conodont genus in the family Gnathodontidae.
Eolinguipolygnathus is an extinct genus of conodont from the Early Devonian (Emsian).
Pseudopolygnathus is an extinct genus of conodonts in the family Polygnathidae.
Ancyrodella is an extinct genus of conodonts from the Late Devonian.
Siphonodella is an extinct genus of conodonts.
Cryptotaxis is an extinct genus of conodonts in the family Cryptotaxidae from the Famennian.
Oulodus is a genus of conodonts in the family Prioniodinidae.
Clydagnathus is a genus of conodonts in the family Cavusgnathidae. Species are known from the Carboniferous of India and the Devonian of Morocco.
References
- ↑ Przemysław Świś (2019). "Population dynamics of the Late Devonian conodont Alternognathus calibrated in days". Historical Biology: An International Journal of Paleobiology. in press. doi:10.1080/08912963.2018.1427088.
- Important candidate sections for stratotype of conodont based Devonian-Carboniferous boundary. Willi Ziegler and Charles A. Sandberg, Courier Forschungsinstitut Senckenberg, 1984
- Palmatolepis-based revision of upper part of standard Late Devonian conodont zonation. Willi Ziegler and Charles A. Sandberg, GSA Special Papers, 1984, volume 196, pages 179–194, doi : 10.1130/SPE196-p179
