Stage 10

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

Stage 10 is an unnamed upper stage of the Furongian series and the whole Cambrian system, corresponding to the Stage 10 age of the Furongian epoch of the Cambrian period. It lasted from approximately 489.5 Ma to around 485.4 Ma (million years ago). It is preceded by the Jiangshanian age of the Furongian and is followed by the Tremadocian age of the Early Ordovician. GSSP and naming have not yet been chosen for this stage. The earliest endocerids are known from Stage 10.

Definition

The GSSP of Stage 10 has not yet been accepted and there are no sections selected as candidates. Stratigraphers propose the first appearance of agnostoid species Lotagnostus americanus as a marker of the lower boundary. The first appearance of conodont Eoconodontus notchpeakensis is also suggested by some researchers.

Coincidences with regional stages

Some regional stages overlap partially or completely with Stage 10. From upper to lower:

Siberia:

• Batyrbaian (upper part)

North America:

• Skullrockian (lower part)

Australia:

• Datsonian
• Payntonian

China:

• Niuchehean

Britain:

• Dolgellian/Trempealeauan
• Festiniogian (upper part)

Life during Stage 10 age

The vast majority of species still lived in the ocean. Kiringellids, ahelled animals probably related to brachiopods or molluscs, lived in the sea soil. Kirengella and Hypseloconus had a cone-shaped curved shell. Brachiopods (Kozhuchinella, Ocnerorthis, Tetralobula) lived on the seabed and fed on suspended matter carried by currents. Rostroconchs, an extinct class of shelled molluscs similar to bivalves, are widely known from marine sediments. Stage 10 genera include Ribeiria, Tolmachovia, Technophorus, Pinnocaris and Cymatopegma. Cephalopods were already quite numerous, although they had not yet reached such a wide distribution as in the Ordovician. Various ellesmerocerids (Antacaroceras, Zhuibianoceras, Huaiheceras, Parapalaeoceras) have been discovered in Siyangshan Formation of China. Eocameroceras, the oldest known endocerid, is known from the same strata.

Olenus

Cambrocaris

Arthropods were probably the most numerous group of animals. Trilobites (Charchaqia, Hedinaspis, Olenus, Proteuloma) and close related agnostids (Trilobagnostus, Leiagnostus, Neoagnostus, Micragnostus) are the most common fossils of this age. Cambrocaris, a small multilegged marine arthropod possibly related to crustaceans, was found in Dolgellian of Poland.

Oneotodus teeth

Among chordates, conodonts were the most abundant. Numerous genera including Cordylodus, Eoconodontus, Monocostodus, Oneotodus and Teridontus inhabited seas on a territory of modern Australia. There is no agreement among scientists whether conodonts were vertebrates. In their lifestyle, conodonts probably resembled today's lampreys and hagfishes. Undoubted vertebrates had probably not yet reached the diversity observed in subsequent periods. Agnathan similar to Ordovician pteraspidomorph Porophoraspis has been reported from Queensland, Australia.

External links

• https://paleobiodb.org/classic/displayTimescale?interval=Stage%2010