| System (period) | Series | Stage (age) | Lower boundary, Ma | |
|---|---|---|---|---|
| Ordovician | Lower | Tremadocian | 485.4±1.9 | |
| Cambrian | Furongian | Stage 10 | ~489.5 | |
| Jiangshanian |  ~494
| |||
| Paibian | ~497
| |||
| Miaolingian | Guzhangian | ~500.5
| ||
| Drumian | ~504.5
| |||
| Wuliuan | ~509
| |||
| Series 2 | Stage 4 | ~514 | ||
| Stage 3 | ~521 | |||
| Terreneuvian | Stage 2 | ~529 | ||
| Fortunian | 538.8±0.2
| |||
| Ediacaran | older | |||
| Subdivisions and "golden spikes" according to IUGS as of September 2023[1] | ||||
The Paibian is a lower stage of the Furongian series, corresponding to the Paibian age of the Furongian epoch. It lasted from approximately 497 Ma to around 494 Ma (million years ago). It is preceded by the Guzhangian age of the Miaolingian and is followed by the Jiangshanian age of the Furongian. The Guzhangian-Paibian extinction ended around 495.5 Ma. The oldest phacopid trilobites are known from this stage.
Paibian corresponds to Idamean stage from the regional Australian chart.
Definition[]
The GSSP of the Paibian stage and the whole Furongian series was ratified in 2003. The lower boundary is fixed at 396 m in the Huaqiao Formation in Wuling Mountains, Huayuan County, Hunan Province, China, and related to the first appearance of agnostoid arthropod Glyptagnostus reticulatus.[2]
Paibian life[]
Paibian fauna is not well known. In many locations in the USA, Sweden, Russia, China and Argentina, only brachiopods, trilobites or agnostids are found in Paibian sediments.
The extinction continued for about 1.5 million years after the end of the previous Guzhangian age. Such animals as anomalocaridids and probably megacheirans became completely extinct. later, biodiversity, which had decreased by 45%, return to its previous level. As before, most living organisms lived in the ocean. Crinoids (Cambrocrinus) and brachiopods (Angulotreta, Obolus, Orusia, Saccogonum) lived in shallow waters. Various graptolites, a group of hemichordates, inhabited seas. Paibian genera include Mastigograptus, Archaeolafoea, Polygonograptus, Desmograptus, Aellograptus and other.
Olenus
Prochuangia
Trilobites remained diverse, although the number of redlichiids declined markedly. Ptychopariid (Dytremacephalus, Shengia, Acrocephalites, Acrocephalaspis), olenid (Protopeltura, Olenus, Stigmatoa, Nganasanella), corynexochid (Prochuangia, Cheilocephalus, Corynexochus, Anhuiaspis), lichid (Paraacidaspis) and asaphid (Proceratopyge, Blandicephalus, Hungaia, Briscoia) trilobites survived. Asteropyge, the earliest phacopid trilobite, is known from the Paibian strata of Huaqiao Formation in China. Agnostids like Glyptagnostus, Pseudagnostus, Agnostus, and Aspidagnostus also remain numerous. Aglaspidids, close relatives of trilobites and agnostids, also existed at that time. Australaglaspis is known from the Idamean (Paibian) sediments of Australia. Among radiodonts, only hurdiids survived, but their fossils of the post-Miaolingian sediments are rare.
Several conodonts are known from the stratotypic sediments of Hunan, China. These include Furnishina, Phakelodus, Muellerodus, Westergaardodina and Prosagittodontus.
References[]
- ↑ "Latest version of international chronostratigraphic chart". International Commission on Stratigraphy. https://stratigraphy.org/chart#latest-version.
- ↑ "GSSP Table - Paleozoic Era". https://timescalefoundation.org/gssp/index.php?parentid=77.