Bashkirian

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.

This article is about the stage of the Carboniferous. For the defunct Russian airline, see BAL Bashkirian Airlines.
Bashkirian
323.2 ± 0.4 – 315.2 ± 0.2 Ma
Chronology
Key events in the Carboniferous
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-350 —
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-345 —
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-340 —
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-335 —
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-330 —
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-325 —
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-320 —
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-315 —
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-310 —
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-305 —
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-300 —
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Key events of the Carboniferous Period
Axis scale: millions of years ago
Etymology
Name formalityFormal
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitAge
Stratigraphic unitStage
Time span formalityFormal
Lower boundary definitionFAD of the Conodont Declinognathodus nodiliferus
Lower boundary GSSPArrow Canyon, Nevada, USA
36.7333°N 114.7778°W / 36.7333; -114.7778
GSSP ratified1996[1]
Upper boundary definitionNot formally defined
Upper boundary definition candidatesFAD of the Conodont Idiognathoides postsulcatus or Declinognathodus donetzianus
Upper boundary GSSP candidate section(s)

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:

Bashkirian life

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

Coelacanths
Actinistia of the Bashkirian
Taxa Presence Location Description Images
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
British Isles A genus of basal amphibians in the family Baphetidae.
Megalocephalus

Temnospondyls
Temnospondyli of the Bashkirian
Taxa Presence Location Description Images
Nova Scotia, Canada;

Jarrow coal mines, Ireland

 Dendrerpeton is a genus of temnospondyl amphibians.
Dendrerpeton
Jarrow coal mines, Ireland A genus of edopoid temnospondyl within the family Cochleosauridae.

Lepospondyls
Lepospondyli of the Bashkirian
Taxa Presence Location Description Images
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
Jarrow coal mines, Ireland A genus of nectridean salamander-like amphibian, a relative of Diplocaulus.
Nova Scotia, Canada A genus of gymnarthrid microsaur.
Jarrow coal mines, Ireland A genus of nectridean amphibian in the family Urocordylidae.
Jarrow coal mines, Ireland A genus of superficially snake-like aistopod amphibian.
Nova Scotia, Canada A genus of hapsidopareiontid microsaur.
Nova Scotia, Canada A genus of microsaur in the family Pantylidae.
Jarrow coal mines, Ireland A genus of nectridean amphibian in the family Urocordylidae.

Reptiliomorphs
Reptiliomorpha of the Bashkirian
Taxa Presence Location Description Images
Rhein-Ruhr-District, West-Germany Bruktererpeton is a genus of gephyrostegid reptiliomorph.
Bruktererpeton
Pholiderpeton
Pteroplax
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.
Bradford, England A species of large eogyrinid embolomere, around 2 meters long. It's the type species of the genus Pholiderpeton.
Newsham, England A species of large eel-like embolomere, around 3 meters long.

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

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

References
  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.

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.

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