Bashkirian

Bashkirian
	323.2 ± 0.4 – 315.2 ± 0.2 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Chronology
	Key events in the Carboniferous -360 — – -355 — – -350 — – -345 — – -340 — – -335 — – -330 — – -325 — – -320 — – -315 — – -310 — – -305 — – -300 — – P; a; l; e; o; z; o; i; c D C; a; r; b; o; n; i; f; e; r; o; u; s P M; i; s; s; i; s; s; i; p; p; i; a; n P; e; n; n; s; y; l; v; a; n; i; a; n L; D E; a; r; l; y M; i; d; d; l; e L; a; t; e E; a; r; l; y M; i; d L; a; t; e C; S Famennian Tournaisian Viséan Serpuk. Bashkirian Moscovian Kasimovian Gzhelian Asselian ← Carboniferous Rainforest Collapse ← Mazon Creek Fossils ← End of Romer's Gap ← Start of Romer's Gap Key events of the Carboniferous Period; Axis scale: millions of years ago
Etymology
Name formality	Formal
Usage information
Celestial body	Earth
Regional usage	Global (ICS)
Time scale(s) used	ICS Time Scale
Definition
Chronological unit	Age
Stratigraphic unit	Stage
Time span formality	Formal
Lower boundary definition	FAD of the Conodont Declinognathodus nodiliferus
Lower boundary GSSP	Arrow Canyon, Nevada, USA; 36.7333°N 114.7778°W
GSSP ratified	1996[1]
Upper boundary definition	Not formally defined
Upper boundary definition candidates	FAD of the Conodont Idiognathoides postsulcatus or Declinognathodus donetzianus
Upper boundary GSSP candidate section(s)	Southern Ural mountains; Nashui, Luodian County, Guizhou, China;

The Bashkirian is in the ICS geologic timescale the lowest stage or oldest age of the Pennsylvanian. The Bashkirian age lasted from 323.2 to 315.2 Ma,[2] is preceded by the Serpukhovian and is followed by the Moscovian.

The Bashkirian overlaps with the upper part of the Namurian and lower part of the Westphalian stages from regional European stratigraphy. It also overlaps with the North American Morrowan and Atokan stages and the Chinese Luosuan and lower Huashibanian stages.[3]

Name and definition

The Bashkirian was named after Bashkiria, the then Russian name of the republic of Bashkortostan in the southern Ural Mountains of Russia, home of the Bashkir people. The stage was introduced by Russian stratigrapher Sofia Semikhatova in 1934.

The base of the Bashkirian is at the first appearance of conodont species Declinognathodus noduliferus. The top of the stage (the base of the Moscovian) is at the first appearance of the conodonts Declinognathodus donetzianus or Idiognathoides postsulcatus,[4] or at the first appearance of fusulinid Aljutovella aljutovica.[5] The GSSP (type location for the base of a stage) for the Bashkirian is in the Battleship Wash Formation at Arrow Canyon, Nevada.[6]

Subdivision

The Bashkirian contains six biozones based on conodont index fossils:

Neognathodus atokaensis Zone
Declinognathodus marginodosus Zone
Idiognathodus sinuosus Zone
Neognathodus askynensis Zone
Idiognathoides sinuatus Zone
Declinognathodus noduliferus Zone

Bashkirian life

Arthropods

Arthropoda of the Bashkirian
Taxa	Presence	Location	Description	Images
Arthropleura	Pennsylvanian	Scotland and northeastern North America	A 2 m (6.6 ft) long millipede	Arthropleura

Cartilaginous fishes

Chondrichthyes of the Bashkirian
Taxa	Presence	Location	Description	Images
Campodus	Carboniferous to Cisuralian	Belgium	A eugeneodontid holocephalian	Campodus Edestus Xenacanthus
Denaea	Pennsylvanian	Kentucky, Ohio, Nebraska, Oklahoma, United States	A symmoriid holocephalian
Edestus	Carboniferous to Cisuralian	England	A eugeneodontid holocephalian
Janassa	Carboniferous to Lopingian	Ohio, Illinois, United States; England	a petalodontiform holocephalian
Hagenoselache	Carboniferous to Cisuralian	Germany	A xenacanthidan elasmobranch
Xenacanthus	Carboniferous to Cisuralian	Scotland, Wales, Ireland	A xenacanthidan elasmobranch

Coelacanths

Actinistia of the Bashkirian
Taxa	Presence	Location	Description	Images
Allenypterus		Bear Gulch Limestone, Montana, USA	A genus of actinistian fish in the family Hadronectoridae, distant relatives to coelacanths.	Allenypterus

Amphibians

Tetrapodomorphs

Tetrapodomorphs of the Bashkirian
Taxa	Presence	Location	Description	Images
Megalocephalus M. pachycephalus		British Isles	A genus of basal amphibians in the family Baphetidae.	Megalocephalus

Temnospondyls

Temnospondyli of the Bashkirian
Taxa	Presence	Location	Description	Images
Dendrerpeton		Nova Scotia, Canada; Jarrow coal mines, Ireland	Dendrerpeton is a genus of temnospondyl amphibians.	Dendrerpeton
Procochleosaurus		Jarrow coal mines, Ireland	A genus of edopoid temnospondyl within the family Cochleosauridae.

Lepospondyls

Lepospondyli of the Bashkirian
Taxa	Presence	Location	Description	Images
Adelospondyli Acherontiscidae Acherontiscus Adelogyrinidae Adelogyrinus Adelospondylus Dolichopareias Palaeomolgophis	Bashkirian	Scotland	An order of rare elongated basal lepospondyls or stem-tetrapods related to Colosteids, that had robust skulls, large eyes and no limbs.	Adelospondylus Palaeomolgophis Ophiderpeton Urocordylus
Keraterpeton		Jarrow coal mines, Ireland	A genus of nectridean salamander-like amphibian, a relative of Diplocaulus.
Leiocephalikon		Nova Scotia, Canada	A genus of gymnarthrid microsaur.
Lepterpeton		Jarrow coal mines, Ireland	A genus of nectridean amphibian in the family Urocordylidae.
Ophiderpeton		Jarrow coal mines, Ireland	A genus of superficially snake-like aistopod amphibian.
Ricnodon		Nova Scotia, Canada	A genus of hapsidopareiontid microsaur.
Trachystegos		Nova Scotia, Canada	A genus of microsaur in the family Pantylidae.
Urocordylus		Jarrow coal mines, Ireland	A genus of nectridean amphibian in the family Urocordylidae.

Reptiliomorphs

Reptiliomorpha of the Bashkirian
Taxa	Presence	Location	Description	Images
Bruktererpeton		Rhein-Ruhr-District, West-Germany	Bruktererpeton is a genus of gephyrostegid reptiliomorph.	Bruktererpeton Pholiderpeton Pteroplax
Pholiderpeton attheyi		Hannah Pit, Newsham, England	A species of giant eogyrinid embolomere, at over 4,5 meters long it was one of the largest carboniferous tetrapods. Originally described as Eogyrinus attheyi, the type species of that genus, it was later subsumed into Pholiderpeton though, according to even later research, it might had not been closely related to the type species of its current genus.
Pholiderpeton scutigerum		Bradford, England	A species of large eogyrinid embolomere, around 2 meters long. It's the type species of the genus Pholiderpeton.
Pteroplax		Newsham, England	A species of large eel-like embolomere, around 3 meters long.

Eureptiles

Eureptilia of the Bashkirian
Taxa	Presence	Location	Description	Images
Hylonomus	Pennsylvanian	Nova Scotia, Canada	A romeriid. It is the earliest known unquestionable reptile.	Hylonomus

Synapsids

Synapsida of the Bashkirian
Taxa	Presence	Location	Description	Images
Asaphestera		Nova Scotia, Canada	Possibly the oldest known synapsid, originally thought to be a lepospondyl.
Protoclepsydrops		Nova Scotia, Canada	Possibly the oldest known synapsid.

References

Lane, H.; Brenckle, Paul; Baesemann, J.; Richards, Barry (December 1999). "The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA". Episodes. 22 (4): 272–283. doi:10.18814/epiiugs/1999/v22i4/003. Retrieved 23 December 2020.
Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.
Heckel, P.H. & Clayton, G.; 2006: The Carboniferous system, use of the new official names for the subsystems, series and stages, Geologica Acta 4(3), pp 403–407.
Nemyrovska, T.I.; 1999: Bashkirian conodonts of the Donets Basin, Ukraine. Scr. Geol. 119, pp 1–115 (in Russian).
Solovieva, M.N.; 1986: Zonal fusulinid scale of the Moscovian Stage based on a revision of the type sections of intrastage subdivisions, Vopr. Mikropaleontol. 28, pp 3–23 (in Russian).
Lane, H.R.; Brenckle, P.L.; Baesemann, J.F. & Richards, B.; 1999: The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA, Episodes 22(4), pp 272–283.

Literature

Menning, M.; Alekseev, A.S.; Chuvashov, B.I.; Davydov, V.I.; Devuyst, F.-X.; Forke, H.C.; Grunt, T.A.; Hance, L.; Heckel, P.H.; Izokh, N.G.; Jin, Y.-G.; Jones, P.J.; Kotlyar, G.V.; Kozur, H.W.; Nemyrovska, T.I.; Schneider, J.W.; Wang, X.-D.; Weddige, K.; Weyer, D. & Work, D.M.; 2006: Global time scale and regional stratigraphic reference scales of Central and West Europe, East Europe, Tethys, South China, and North America as used in the Devonian–Carboniferous–Permian Correlation Chart 2003 (DCP 2003), Palaeogeography, Palaeoclimatology, Palaeoecology 240(1-2): pp 318–372.

External links

Carboniferous timescale at the website of the Norwegian network of offshore records of geology and stratigraphy
Bashkirian, Geowhen Database

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[1] Lane, H.; Brenckle, Paul; Baesemann, J.; Richards, Barry (December 1999). "The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA". Episodes. 22 (4): 272–283. doi:10.18814/epiiugs/1999/v22i4/003. Retrieved 23 December 2020.

[2] Gradstein, F.M.; Ogg, J.G. & Smith, A.G.; 2004: A Geologic Time Scale 2004, Cambridge University Press.

[3] Heckel, P.H. & Clayton, G.; 2006: The Carboniferous system, use of the new official names for the subsystems, series and stages, Geologica Acta 4(3), pp 403–407.

[4] Nemyrovska, T.I.; 1999: Bashkirian conodonts of the Donets Basin, Ukraine. Scr. Geol. 119, pp 1–115 (in Russian).

[5] Solovieva, M.N.; 1986: Zonal fusulinid scale of the Moscovian Stage based on a revision of the type sections of intrastage subdivisions, Vopr. Mikropaleontol. 28, pp 3–23 (in Russian).

[6] Lane, H.R.; Brenckle, P.L.; Baesemann, J.F. & Richards, B.; 1999: The IUGS boundary in the middle of the Carboniferous: Arrow Canyon, Nevada, USA, Episodes 22(4), pp 272–283.