| System (period) | Series (epoch) | Stage (age) | Lower boundary, Ma | |
|---|---|---|---|---|
| Paleogene | Paleocene | Danian | 66,0 | |
| Cretaceous | Upper (Late) | Maastrichtian |  72.1±0.2
| |
| Campanian | 83.6±0.2
| |||
| Santonian | 86.3±0.5
| |||
| Coniacian | 89.8±0.3
| |||
| Turonian | 93.9
| |||
| Cenomanian | 100.5
| |||
| Lower (Early) | Albian | ~113.0
| ||
| Aptian | ~121.4 | |||
| Barremian | 125.77* | |||
| Hauterivian | ~132.6
| |||
| Valanginian | ~139.8 | |||
| Berriasian | ~145.0 | |||
| Jurassic | Upper | Tithonian | older | |
| Subdivisions and "golden spikes" according to IUGS as of September 2023[1] *A golden spike is seen in chart but not ratified yet. | ||||
The Albian is a sixth and upper stage of the Lower Cretaceous series, corresponding to the Albian age of the Early Cretaceous epoch. It lasted from approximately 113.0 Ma to around 100.5 Ma (million years ago). It is preceded by the Aptian age of the Early Cretaceous and is followed by the Cenomanian age of the Late Cretaceous.
The last temnospondyls existed during this age.
Definition[]
The GSSP of the Albian stage was ratified in 2016. The lower boundary is fixed in the Marnes Bleues Formation in France, and related to the first appearance of the planktonic foraminiferan Microhedbergella renilaevis.[2]
Albian life[]
Numerous bivalves lived on the seabed, and cephalopod ammonites swam in the water column above them. Albian ammonites include genera Hypacanthoplites, Sonneratia, Otohoplites and Protohoplites. Bony fish of the time include members of the extinct order Ellimmichthyiformes such as Ellimmichthys, Diplomystus, Foreyclupea and Armigatus. Coelacanths like Axelrodichthys were still quite common. The diversity of ichthyosaurs gradually declined, although their fossils are still not very rare in Albian deposits. Most of them belong to the genus Platypterygius, its specimens have been reported from the Albian of Australia, Eupore and North America. Its close relatives, Sisteronia and Maiaspondylus, were found in France and Canada respectively. Among the plesiosaurs, long-necked elasmosaurids like Eromangasaurus have been spreading. Around this time, some dinosaurs transitioned to life in the sea. These were birds (avian dinosaurs) of the order Hesperornithiformes. Enaliornis, probably the oldest of them, is known from the Late Albian of Gault Formation in the United Kingdom.
Several Deinonychus attacking Tenontosaurus
Land dinosaurs became more and more diverse, spreading across all continents. The most numerous were ornithopods with such animals as Altirhinus, Tenontosaurus, Ouranosaurus and Muttaburrasaurus known from Asia, North America, Africa and Australia respectively. Herds of these herbivores, eating low vegetation, probably influenced such giant animals as sauropods, whose numbers by this time were falling markedly, especially in the northern hemisphere. Despite this, some of them grew to enormous sizes. Sauroposeidon, one of the highest land animal, existed in North Aremica during this age. Patagotitan, another huge sauropod, lived in what is now Argentina. Thyreophoran armoured polacanthids grazed on the plains and near the coasts.
All these animals were hunted by a variety of theropods from small and medium-sized dromaeosaurids like Deinonychus to huge carcharodontosaurids like Acrocanthosaurus, Eocarcharia, Carcharodontosaurus and Tyrannotitan. Several theropods like Harpymimus probably became omnivores. One theropod family, Abelisauridae, spread primarily on southern continents. However, Genusaurus, one of the earliest abelisaurid, inhabited the territory of modern France. Kryptops, another abelisaurid, was discovered in Aptian-Albian strata of Niger where the fish-eating Suchomimus, a spinosaurid, has also been found.
The rivers and lakes were home to numerous turtles (Teneremys, Taquetochelys, Hangaiemys), choristoderes (Tchoiria, Khurendukhosaurus, Irenosaurus) and crocodylomorphs (Elosuchus). Sarcosuchus, the giant relative of modern crocodiles, lived in what is now northern Africa. Notosuchia, a special group of crocodylomorphs, transitioned to life on land. The unusual duck-billed Anatosuchus reached only about 70 cm in length and lived together with large Sarcosuchus and dinosaurs.
Albian is the last age when temnospondyls existed. The last known member of these ancient group of amphibians is Koolasuchus whose fossils were found in the state of Victoria, Australia. The reason why temnospondyls survived for so long in this region may be due to climate conditions or geographic isolation from more northern territories by mountains, deserts, etc.
References[]
- ↑ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. https://stratigraphy.org/chart#latest-version.
- ↑ "GSSP Table - Mesozoic Era". https://timescalefoundation.org/gssp/index.php?parentid=35.