Bathonian
From Wikipedia, the free encyclopedia
In the geologic timescale the Bathonian epoch is a stage during the Middle Jurassic, of the Mesozoic era of the Phanerozoic eon. It lasted from approximately 167.7 Ma to around 164.7 Ma (million years ago). The Bathonian age succeeds the Bajocian age and precedes the Callovian age.
The stage takes its name from Bath, a spa town in England built on Jurassic limestone.
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[edit] Vertebrate Fauna
[edit] Dinosaurs
Dinosaurs were vertebrate animals that dominated terrestrial ecosystems for over 160 million years, first appearing approximately 230 million years ago. At the end of the Cretaceous Period, 65 million years ago, a catastrophic extinction event ended the dominance of dinosaurs on land.
- Agilisaurus louderbacki
- A four foot long bipedal herbivore that was built for speed. It was discovered in one of China's many Callovian deposits.
- A sauropod named after the mountains where the mythological figure that held the world on his shoulders, it attained lengths of 15 meters (50 feet) and lived in Morocco.
- A poorly known English sauropod with heart shaped teeth.
- Iliosuchus Image:Megalosaurus dinosaur.pngThe carnivorous Megalosaurus was a Bathonian theropod dinosaur.
- A small, 5 foot long European carnivore related to Tyrannosaurus.
- The first dinosaur to receive a formal scientific description, Megalosaurus was a 30 foot carnivore which prowled Jurassic England.
- Tianchisaurus nedegoapeferima
- A Chinese ankylosaur which lacked a club at the end of its tail. Its species epithet honors the main actors of Jurassic Park.
- Xiaosaurus dashanpensis
- A poorly known Chinese ornithschian that may be related to Hypsilophodon and Lesothosaurus. It was small and vegetarian.
- Yandusaurus hongheensis
- A 5 foot long Chinese herbivore in the family hypsilophodontidae.
[edit] Thalattosuchians
Thalattosuchia is the name given to a clade of marine crocodylomorphs from the Early Jurassic to the Early Cretaceous that had a cosmopolitan distribution.
- An opportunistic carnivore that fed on fish, belemnites and other marine animals and possible carrion. Metriorhynchus grew to an average adult length of 3 meters (9.6 feet), although some individuals may have reached lengths rivaling those of large nile crocodiles.
- The most plesiomorphic known metriorhynchid.
[edit] Invertebrate Fauna
[edit] Ammonitida
Members of the order ammonitda are known as Ammonitic ammonites. They are distinguished primarily by their suture lines. In ammonitic suture patterns, the lobes and saddles are much subdivided (fluted) and subdivisions are usually rounded instead of saw-toothed. Ammonoids of this type are the most important species from a biostratigraphical point of view. This suture type is characteristic of Jurassic and Cretaceous ammonoids but extends back all the way to the Permian.
[edit] Genera Surviving From the Bajocian Stage
The following genera of Ammonites first appear in Bajocian rocks, but survived to this article's eponymous stage.
- Asphinctites
- Cadomites
- Cranocephalites
- Epistrenoceras
- Garantiana
- Lissoceras
- Nannolytoceras
- Oecoptychius
- Oecotraustes
- Okribites
- Oxycerites
- Parkinsonia
- Procerites
- Siemiradzkia
- Somalinautilus
[edit] Belemnites
Belemnites (or belemnoids) are an extinct group of marine cephalopod, very similar in many ways to the modern squid and closely related to the modern cuttlefish. Like them, the belemnites possessed an ink sac, but, unlike the squid, they possessed ten arms of roughly equal length and no tentacles.
[edit] Genera Surviving From the Bajocian
The following genera of Belemnites first appear in Bajocian rocks, but survived to this article's eponymous stage.
- Produvalia
| Jurassic period | ||
|---|---|---|
| Lower/Early Jurassic | Middle Jurassic | Upper/Late Jurassic |
| Hettangian | Sinemurian Pliensbachian | Toarcian | Aalenian | Bajocian Bathonian | Callovian | Oxfordian | Kimmeridgian Tithonian |
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