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{{Short description|Extinct genus of tetrapodomorphs}}
{{expand french|topic=paleontology|date=January 2023}}
{{speciesbox
{{speciesbox
| fossil_range = [[Late Devonian]]
| fossil_range = {{fossilrange|Frasnian|Frasnian|[[Frasnian]]}}
| image = Elpistostege watsoni1.JPG
| image = Elpistostege watsoni.jpg
| image_caption = Fossil skull
| image_caption = ''Elpistostege watsoni'' on display at the Miguasha National Park
⚫
| display_parents = 3
| parent_authority = [[Thomas Stanley Westoll|Westoll]], 1938
| parent_authority = [[Thomas Stanley Westoll|Westoll]], 1938
| genus = Elpistostege
| genus = Elpistostege
| species = watsoni
| species = watsoni
| authority = Westoll, 1938
| authority = Westoll, 1938
⚫
| display_parents = 3
}}
}}
⚫
{{Portal|Paleontology}}
'''''Elpistostege''''' is an [[extinct]] genus of [[tetrapod]]-like [[vertebrate]] that lived in the [[Late Devonian]] period (Late [[Givetian]] to Early [[Frasnian]]). [[Fossils]] of its skull and a part of its [[Vertebral column|backbone]] have been found in rocks of the [[Escuminac Formation]] in [[Quebec]], [[Canada]]. A complete specimen of the animal has since been found in the same formation. It has been proposed, by the palaeontologist [[Richard Cloutier]] at [[Université du Québec à Rimouski]], that this species may dethrone its close relative ''[[Tiktaalik]]'' in the position of the most primitive stem-tetrapod, though phylogenetic analyses have shown them to be very close relatives.
The fossil suggests that human hands likely evolved, eventually, from the fins of this fish, according to Cloutier, who claimed "It is the first time that digits, as seen in tetrapods, are found in a fin covered by scales and fin rays, as seen in fishes."<ref>https://www.livescience.com/ancient-fish-fingers.html</ref>


'''''Elpistostege''''' is an [[extinct]] [[genus]] of finned [[tetrapodomorph]]s that lived during the [[Frasnian]] age of the [[Late Devonian]] epoch. Its only known species, '''''E. watsoni''''', was first described in 1938 by the British palaeontologist [[Thomas Stanley Westoll]], based on a single partial [[skull roof]] discovered at the [[Escuminac Formation]] in [[Quebec]], [[Canada]].<ref name="Westoll1938" />
[[File:Elpistostege watsoni.jpg|center|thumb|''Elpistostege watsoni'' on display at the Miguasha National Park.]]

In 2010, a complete specimen was found in the same formation, which was described by Richard Cloutier and colleagues in 2020. It reveals that the paired fins of ''Elpistostege'' contained bones [[Homology (biology)|homologous]] to the [[phalanges]] (digit bones) of modern [[tetrapod]]s; it is the most [[basal (phylogenetics)|basal]] tetrapodomorph known to possess these bones. At the same time, the fins were covered in scales and [[lepidotrichia]] (fin rays), which indicates that the origin of phalanges preceded the loss of fin rays, rather than the other way around.<ref name="Cloutier2020" /><ref name="Livescience" />


==Relationships==
==Relationships==
An analysis conducted by Swartz in 2012 found ''Elpistostege'' to be the sister taxon of ''[[Tiktaalik]]''. Both were found to be primitive members of the group [[Stegocephalia]], along with other primitive stem-tetrapods.<ref name=SB12>{{cite journal | last = Swartz | first = B. | year = 2012 | title = A marine stem-tetrapod from the Devonian of Western North America | journal = PLoS ONE | pmid = 22448265 | volume = 7 | issue = 3 | pmc = 3308997 | pages = e33683 | doi = 10.1371/journal.pone.0033683 | url = http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0033683;jsessionid=E4E007B3FAC50B3B0C7C2B8B0CBE3F83 }}</ref>
An analysis conducted by Swartz in 2012 found ''Elpistostege'' to be the sister taxon of ''[[Tiktaalik]]''. Both were found to be primitive members of the group [[Elpistostegalia]], along with other advanced stem-tetrapods.<ref name="Swartz2012" />


{{clade| style=font-size:85%;line-height:85%
{{clade|style=font-size:85%;line-height:85%
|label1=[[Elpistostegalia]]
|label1=[[Elpistostegalia]]
|1={{clade
|1={{clade
|1=''[[Panderichthys]]'' [[File:Panderichthys BW.jpg|70 px]]
|1=''[[Panderichthys]]'' <span style="{{MirrorH}}">[[File:Panderichthys BW.jpg|70 px]]</span>
|label2=Stegocephalia
|label2=[[Stegocephalia]] |sublabel2=sensu Laurin, 1998
|2={{clade
|2={{clade
|1={{clade
|1={{clade
|1=''[[Tiktaalik]]'' [[File:Tiktaalik BW.jpg|70 px]]
|1=''[[Tiktaalik]]'' <span style="{{MirrorH}}">[[File:Tiktaalik restoration (side view) by ObsidianSoul 02.png| 70px]]</span>
|2='''''Elpistostege'''''}}
|2='''''Elpistostege'''''}}
|label2=[[Stegocephali]] |sublabel2=sensu Laurin, 2020
⚫
|2={{clade
|2={{clade
|1=''[[Elginerpeton]]'' [[File:Elginerpeton BW.jpg|70 px]]
|1=''[[Elginerpeton]]'' [[File:Elginerpeton BW.jpg|70 px]]
⚫
|2={{clade
|2={{clade
|1=''[[Ventastega]]''
|1=''[[Ventastega]]'' <span style="{{MirrorH}}">[[File:Ventastega life restoration white background.jpg|70 px]]</span>
|2={{clade
|2={{clade
|1=''[[Acanthostega]]'' [[File:Acanthostega BW.jpg|70 px]]
|1=''[[Acanthostega]]'' [[File:Acanthostega model (for cladogram).png|70 px]]
|2={{clade
|2={{clade
|1=''[[Ichthyostega]]'' [[File:Ichthyostega BW.jpg|70 px]]
|1=''[[Ichthyostega]]'' [[File:Ichthyostega model-removebg.png|70 px]]
|2={{clade
|2={{clade
|1=[[Whatcheeriidae]] [[File:Pederpes22small.jpg|70 px]]
|1=[[Whatcheeriidae]] <span style="{{MirrorH}}">[[File:Pederpes22small.jpg|70 px]]</span>
|2={{clade
|2={{clade
|1=[[Colosteidae]] [[File:Greererpeton BW.jpg|70 px]]
|1=[[Colosteidae]] <span style="{{MirrorH}}">[[File:Greererpeton BW.jpg|70 px]]</span>
|2={{clade
⚫
|2={{clade
|1=''[[Crassigyrinus]]'' [[File:Crassigyrinus BW.jpg|70 px]]
|1=''[[Crassigyrinus]]'' [[File:Crassigyrinus BW.jpg|70 px]]
|2={{clade
⚫
|2={{clade
|1=[[Baphetidae]]
|2=[[Crown group]] [[Tetrapoda]] [[File:Seymouria BW.jpg|70 px]]
|1=[[Baphetidae]] <span style="{{MirrorH}}">[[File:Loxomma1DB.jpg|70 px]]</span>
|2=[[Crown group]] [[Tetrapoda]] <span style="{{MirrorH}}">[[File:Seymouria2.jpg|70 px]]</span>
}} }} }} }} }} }} }} }} }} }} }}
}} }} }} }} }} }} }} }} }} }} }}


A 2020 paper instead recovers ''Elpistostege'' as the sister taxon of all tetrapods, crownward of ''Tiktaalik'':<ref name=Cloutier2020>{{cite journal |last1=Cloutier |first1=R. |last2=Clement |first2=A. M. |last3=Lee |first3=M. S. Y. |last4=Noël |first4=R. |last5=Béchard |first5=I. |last6=Roy |first6=V. |last7=Long |first7=J. A. |title=Elpistostege and the origin of the vertebrate hand |journal=Nature |date=2020 |volume=579 |issue=7800 |pages=549–554 |doi=10.1038/s41586-020-2100-8}}</ref>
The 2020 study by Cloutier ''et al.'' instead recovers ''Elpistostege'' as the sister taxon of all limbed vertebrates, crownward of ''Tiktaalik'':<ref name="Cloutier2020" />


{{clade| style=font-size:85%;line-height:85%
{{clade| style=font-size:85%;line-height:85%
|1={{clade
|1={{clade
|1=''[[Panderichthys]]'' [[File:Panderichthys BW.jpg|70 px]]
|1=''[[Panderichthys]]'' <span style="{{MirrorH}}">[[File:Panderichthys BW.jpg|70 px]]</span>
|2={{clade
|2={{clade
|1={{clade
|1={{clade
|1=''[[Tiktaalik]]'' [[File:Tiktaalik BW.jpg|70 px]]
|1=''[[Tiktaalik]]'' <span style="{{MirrorH}}">[[File:Tiktaalik restoration (side view) by ObsidianSoul 02.png| 70px]]</span>
|2={{clade
|2={{clade
|1='''''Elpistostege'''''
|1='''''Elpistostege'''''
|label2=Limbed vertebrates
|label2=Tetrapoda (apomorphy-based)
|2={{clade
|2={{clade
|1=''[[Ventastega]]'' <span style="{{MirrorH}}">[[File:Ventastega life restoration white background.jpg|70 px]]</span>
|1=''[[Ventastega]]''
|2={{clade
|2={{clade
|1=''[[Acanthostega]]'' [[File:Acanthostega BW.jpg|70 px]]
|1=''[[Acanthostega]]'' [[File:Acanthostega model (for cladogram).png|70 px]]
|2={{clade
|2={{clade
|1=''[[Ichthyostega]]'' [[File:Ichthyostega BW.jpg|70 px]]
|1=''[[Ichthyostega]]'' [[File:Ichthyostega model-removebg.png|70 px]]
|2=''[[Tulerpeton]]''
|2=''[[Tulerpeton]]'' <span style="{{MirrorH}}">[[File:Tulerpeton12DB.jpg|70 px]]</span>
}} }} }} }} }} }} }} }}
}} }} }} }} }} }} }} }}


==References==
==References==
{{Reflist}}
{{Reflist|refs=
<ref name="Cloutier2020">{{cite journal |last1=Cloutier |first1=R. |last2=Clement |first2=A. M. |last3=Lee |first3=M. S. Y. |last4=Noël |first4=R. |last5=Béchard |first5=I. |last6=Roy |first6=V. |last7=Long |first7=J. A. |title=''Elpistostege'' and the origin of the vertebrate hand |journal=Nature |date=2020 |volume=579 |issue=7800 |pages=549–554 |doi=10.1038/s41586-020-2100-8|pmid=32214248 |bibcode=2020Natur.579..549C |s2cid=213171029 }}</ref>
<ref name="Livescience">{{cite news |last1=Geggel |first1=Laura |title=Fish sprouted fingers before they ventured onto land, fossil shows |url=https://www.livescience.com/ancient-fish-fingers.html |work=livescience.com |date=2020 |language=en}}</ref>
<ref name="Swartz2012">{{cite journal | last = Swartz | first = B. | year = 2012 | title = A marine stem-tetrapod from the Devonian of Western North America | journal = PLOS ONE | pmid = 22448265 | volume = 7 | issue = 3 | pmc = 3308997 | pages = e33683 | doi = 10.1371/journal.pone.0033683 | bibcode = 2012PLoSO...733683S | doi-access = free }}</ref>
<ref name="Westoll1938">{{cite journal |last1=Westoll |first1=T. S. |title=Ancestry of the Tetrapods |journal=Nature |date=1938 |volume=141 |issue=3559 |pages=127–128 |doi=10.1038/141127a0|bibcode=1938Natur.141..127W |s2cid=4086668 }}</ref>
}}


==External links==
==External links==
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* [http://www.radio-canada.ca/nouvelles/science/2013/10/30/002-elpistostege-watsoni-presentation-la.shtml Recent Discovery of an entire well-preserved fossil of ''Elpistostege watsoni'']
* [http://www.radio-canada.ca/nouvelles/science/2013/10/30/002-elpistostege-watsoni-presentation-la.shtml Recent Discovery of an entire well-preserved fossil of ''Elpistostege watsoni'']


⚫
{{Portal|Paleontology}}
{{Tetrapodomorpha|St.}}
{{Tetrapodomorpha|St.}}
{{Taxonbar|from=Q3723656}}
{{Taxonbar|from=Q3723656}}


⚫
[[Category:Elpistostegalians]]
[[Category:Prehistoric lobe-finned fish genera]]
[[Category:Prehistoric lobe-finned fish genera]]
[[Category:Stegocephalians]]
[[Category:Late Devonian sarcopterygians]]
[[Category:Late Devonian animals]]
[[Category:Devonian sarcopterygians of North America]]
⚫
[[Category:Late Devonian fish]]
⚫
[[Category:Devonian bony fish]]
[[Category:Devonian animals of North America]]
[[Category:Paleozoic life of Quebec]]
[[Category:Paleozoic life of Quebec]]
[[Category:Transitional fossils]]
[[Category:Fossil taxa described in 1938]]
⚫
[[Category:Frasnian genera]]




{{paleo-lobefinned-fish-stub}}
{{Paleo-tetrapodomorph-stub}}
{{Devonian-animal-stub}}

Latest revision as of 16:04, 28 March 2024

Elpistostege
Temporal range: Frasnian
Elpistostege watsoni on display at the Miguasha National Park
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Sarcopterygii
Clade: Tetrapodomorpha
Clade: Stegocephali
Family: †Elpistostegidae
Genus: †Elpistostege
Westoll, 1938
Species:
†E. watsoni
Binomial name
†Elpistostege watsoni
Westoll, 1938

Elpistostege is an extinct genus of finned tetrapodomorphs that lived during the Frasnian age of the Late Devonian epoch. Its only known species, E. watsoni, was first described in 1938 by the British palaeontologist Thomas Stanley Westoll, based on a single partial skull roof discovered at the Escuminac Formation in Quebec, Canada.[1]

In 2010, a complete specimen was found in the same formation, which was described by Richard Cloutier and colleagues in 2020. It reveals that the paired fins of Elpistostege contained bones homologous to the phalanges (digit bones) of modern tetrapods; it is the most basal tetrapodomorph known to possess these bones. At the same time, the fins were covered in scales and lepidotrichia (fin rays), which indicates that the origin of phalanges preceded the loss of fin rays, rather than the other way around.[2][3]

Relationships

[edit]

An analysis conducted by Swartz in 2012 found Elpistostege to be the sister taxon of Tiktaalik. Both were found to be primitive members of the group Elpistostegalia, along with other advanced stem-tetrapods.[4]

Elpistostegalia

The 2020 study by Cloutier et al. instead recovers Elpistostege as the sister taxon of all limbed vertebrates, crownward of Tiktaalik:[2]

References

[edit]
  1. ^ Westoll, T. S. (1938). "Ancestry of the Tetrapods". Nature. 141 (3559): 127–128. Bibcode:1938Natur.141..127W. doi:10.1038/141127a0. S2CID 4086668.
  2. ^ a b Cloutier, R.; Clement, A. M.; Lee, M. S. Y.; Noël, R.; Béchard, I.; Roy, V.; Long, J. A. (2020). "Elpistostege and the origin of the vertebrate hand". Nature. 579 (7800): 549–554. Bibcode:2020Natur.579..549C. doi:10.1038/s41586-020-2100-8. PMID 32214248. S2CID 213171029.
  3. ^ Geggel, Laura (2020). "Fish sprouted fingers before they ventured onto land, fossil shows". livescience.com.
  4. ^ Swartz, B. (2012). "A marine stem-tetrapod from the Devonian of Western North America". PLOS ONE. 7 (3): e33683. Bibcode:2012PLoSO...733683S. doi:10.1371/journal.pone.0033683. PMC 3308997. PMID 22448265.
[edit]


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