View source for Embolomeri

{{Short description|Extinct order of tetrapods}}
{{Automatic taxobox
| name = Embolomeres
| fossil_range = [[Mississippian age|Mississippian]] - [[Wuchiapingian]]{{fossilrange|330|254|}}
| image = Archeria2DB.jpg
| image_caption = Restoration of ''[[Archeria (animal genus)|Archeria]]'' from the Lower Permian of Texas.
| display_parents = 2
| taxon = Embolomeri
| authority = [[Edward Drinker Cope|Cope]], [[1885 in paleontology|1885]]
| subdivision_ranks = Genera
| subdivision = See text.
}}
'''Embolomeri''' is an [[Order (biology)|order]] of [[Tetrapod|tetrapods]] or [[Stem-group|stem]]-tetrapods, possibly members of [[Reptiliomorpha]]. Embolomeres first [[evolution|evolved]] in the Early [[Carboniferous]] ([[Mississippian age|Mississippian]]) Period and were the largest and most successful predatory tetrapods of the Late Carboniferous ([[Pennsylvanian (geology)|Pennsylvanian]]) Period. They were specialized semiaquatic predators with long bodies for eel-like undulatory swimming. Embolomeres are characterized by their [[Vertebra|vertebral centra]], which are formed by two cylindrical segments, the pleurocentrum at the rear and intercentrum at the front. These segments are equal in size. Most other tetrapods have pleurocentra and intercentra which are drastically different in size and shape.<ref>{{Cite journal|last=Panchen|first=A. L.|date=10 February 1972|title=The skull and skeleton of ''Eogyrinus attheyi'' Watson (Amphibia: Labyrinthodontia)|journal=Phil. Trans. R. Soc. Lond. B|language=en|volume=263|issue=851|pages=279–326|doi=10.1098/rstb.1972.0002|bibcode=1972RSPTB.263..279P|issn=0080-4622|doi-access=free}}</ref>

Embolomeres were among the earliest large carnivorous tetrapods, with members such as the crocodilian-like ''[[Proterogyrinus]]'' appearing in the [[Viséan|Visean]] stage of the Carboniferous. They declined in diversity during the Permian period, though at least one representative (''[[Archeria (animal)|Archeria]])'' was common in the [[Early Permian]].<ref name=":1" /> Embolomeres went extinct shortly before the end of the Permian.<ref>{{Cite journal|last1=Chen|first1=Jianye|last2=Liu|first2=Jun|date=2020-12-01|title=The youngest occurrence of embolomeres (Tetrapoda: Anthracosauria) from the Sunjiagou Formation (Lopingian, Permian) of North China|url=https://fr.copernicus.org/articles/23/205/2020/|journal=Fossil Record|language=English|volume=23|issue=2|pages=205–213|doi=10.5194/fr-23-205-2020|issn=2193-0066|doi-access=free}}</ref>

==Classification==
[[File:The Osteology of the Reptiles p98.png|left|thumb|208x208px|Vertebrae from several different tetrapods, with those of "''Cricotus''" (''[[Archeria (animal)|Archeria]]'') in A-C, showing the large, cylindrical intercentra (I) and pleurocentra (P)]]
The order Embolomeri was first named by [[Edward Drinker Cope]] in 1884 during his revision of "[[Batrachia|batrachian]]" ([[amphibian]]) evolution. Embolomeri was differentiated from several other newly named amphibian orders, such as "[[Rachitomi]]", by the presence of intercentra and pleurocentra of the same size and shape, that being large cylinders. At the time, embolomere fossils were uncommon, so Cope could only identify "cricotids" such as ''[[Cricotus]]'' as possessing embolomerous vertebrae.<ref name=":0">{{Cite journal|last=Cope|first=E.D.|date=January 1884|title=The Batrachia of the Permian Period of North America|journal=The American Naturalist|volume=18|pages=26–39|doi=10.1086/273563|s2cid=84133633}}</ref> The genus name "''Cricotus''" is dubious, as it has been used by Cope to refer to embolomere fossils spanning anywhere between mid-[[Pennsylvanian (geology)|Pennsylvanian]] deposits of Illinois and the Permian [[Red Beds of Texas and Oklahoma|red beds]] of [[Texas]]. Most paleontologists now refer the red bed "''Cricotus''" specimens to the genus ''Archeria''.<ref name=":1">{{Cite journal|last=Romer|first=Alfred Sherwood|date=11 January 1957|title=The Appendicular Skeleton of the Permian Embolomerous Amphibian ''Archeria''|url=https://deepblue.lib.umich.edu/bitstream/handle/2027.42/48305/ID145.pdf?sequence=2|journal=Contributions from the Museum of Paleontology|volume=13|issue=5|pages=105–159}}</ref>

[[Michel Laurin]] (1998) formally defined Embolomeri as "the [[Most recent common ancestor|last common ancestor]] of ''Proterogyrinus'' and ''Archeria'' and all of its descendants."<ref>{{Cite journal|last=Laurin|first=Michel|date=1998|title=The importance of global parsimony and historical bias in understanding tetrapod evolution. Part I. Systematics, middle ear evolution and jaw suspension|url=https://www.academia.edu/1177174|journal=Annales des Sciences Naturelles - Zoologie et Biologie Animale|volume=19|issue=1|pages=1–42|doi=10.1016/S0003-4339(98)80132-9}}</ref> This definition excludes ''[[Eoherpeton]]'', which is almost always considered a close ally of the group. Some authors place ''[[Silvanerpeton]]'' or [[Chroniosuchia|chroniosuchians]] as close relatives as well, though they are generally agreed to lie outside Embolomeri proper.<ref>{{Cite journal|last1=Chen|first1=Jianye|last2=Liu|first2=Jun|date=2020-12-01|title=The youngest occurrence of embolomeres (Tetrapoda: Anthracosauria) from the Sunjiagou Formation (Lopingian, Permian) of North China|url=https://fr.copernicus.org/articles/23/205/2020/|journal=Fossil Record|language=en|volume=23|issue=2|pages=205–213|doi=10.5194/fr-23-205-2020|issn=2193-0066|doi-access=free}}</ref><ref>{{Cite journal|last1=Klembara|first1=Jozef|last2=Clack|first2=Jennifer A.|last3=Čerňanský|first3=Andrej|date=2010-09-16|title=The anatomy of palate of Chroniosaurus dongusensis (Chroniosuchia, Chroniosuchidae) from the Upper Permian of Russia|journal=Palaeontology|language=en|volume=53|issue=5|pages=1147–1153|doi=10.1111/j.1475-4983.2010.00999.x|issn=0031-0239}}</ref><ref>{{Cite journal|last=Carroll|first=Robert L.|date=2012-10-18|title=The Importance of Recognizing Our Limited Knowledge of the Fossil Record in the Analysis of Phylogenetic Relationships among Early Tetrapods|journal=Fieldiana Life and Earth Sciences|language=en-US|volume=5|pages=5–16|doi=10.3158/2158-5520-5.1.5|s2cid=85114894|issn=2158-5520}}</ref><ref>{{Cite journal|last1=Sookias|first1=Roland B.|last2=Böhmer|first2=Christine|last3=Clack|first3=Jennifer A.|date=2014-10-07|title=Redescription and Phylogenetic Analysis of the Mandible of an Enigmatic Pennsylvanian (Late Carboniferous) Tetrapod from Nova Scotia, and the Lability of Meckelian Jaw Ossification|journal=PLOS ONE|language=en|volume=9|issue=10|pages=e109717|doi=10.1371/journal.pone.0109717|issn=1932-6203|pmc=4188710|pmid=25290449|bibcode=2014PLoSO...9j9717S|doi-access=free}}</ref>

The poorly-defined group '''Anthracosauria''' is sometimes considered synonymous with Embolomeri, and the group's namesake, ''[[Anthracosaurus]]'', is an embolomere. However, other authors use the term "Anthracosauria" in reference to a broader group which includes embolomeres in combination with various other reptile-like amphibians ([[Reptiliomorpha|reptiliomorphs]]). Reptiliomorphs are all tetrapods more closely related to living reptiles and synapsids (mammals and their ancestors), rather than living amphibians. Despite this, reptiliomorphs likely had amphibian-like biological traits, such as water-based reproduction.

Many studies conducted since the 1990s have also placed the group [[Lepospondyli]] as closer to amniotes than embolomeres were. Lepospondyls are a particularly unusual group of tetrapods, with some members (i.e. [[Brachystelechidae|brachystelechids]]) very similar to lissamphibians and others (i.e. [[Tuditanidae|tuditanids]]) very similar to amniotes. If lepospondyls are both close relatives of amniotes and the ancestors of modern amphibians, then that means that crown-Tetrapoda (descendants of the common ancestor to all living tetrapods) is a much more restricted group than previously assumed. In this situation, various traditional orders of Tetrapoda such as Embolomeri and Temnospondyli actually would qualify as stem-tetrapods due to having evolved prior to the split between modern amphibians and amniotes.<ref name="LR99">{{cite journal|last=Laurin|first=M.|author2=Reisz, R.R.|year=1999|title=A new study of ''Solenodonsaurus janenschi'', and a reconsideration of amniote origins and stegocephalian evolution|url=https://www.academia.edu/1177181|journal=Canadian Journal of Earth Sciences|volume=36|issue=8|pages=1239–1255|doi=10.1139/e99-036}}</ref>

However, most authors consider temnospondyls to be the ancestors of modern amphibians. This would suggest that embolomeres are likely reptiliomorphs (closer to reptiles) and within the clade Tetrapoda.<ref name="RCQ03" /> However, even this classification is not stable, as some analyses have found embolomeres to be more basal than temnospondyls.<ref>{{Cite journal|last=Clack|first=J. A.|date=July 2002|title=An early tetrapod from 'Romer's Gap'|journal=Nature|language=En|volume=418|issue=6893|pages=72–76|doi=10.1038/nature00824|pmid=12097908|s2cid=741732|issn=0028-0836}}</ref>

Below is a [[cladogram]] from Ruta ''et al.'' (2003):<ref name=RCQ03>{{cite journal |author=Marcello Ruta, Michael I. Coates and Donald L. J. Quicke |year=2003 |title=Early tetrapod relationships revisited |url=http://pondside.uchicago.edu/oba/faculty/coates/5.RutCoaQuick2003.pdf |journal=Biological Reviews |volume=78 |issue=2 |pages=251–345 |doi=10.1017/S1464793102006103 |pmid=12803423 |s2cid=31298396 |access-date=2012-05-26 |archive-date=2008-05-22 |archive-url=https://web.archive.org/web/20080522124644/http://pondside.uchicago.edu/oba/faculty/coates/5.RutCoaQuick2003.pdf |url-status=dead }}</ref>

{{clade| style=font-size:100%;line-height:100%
|label1=[[Tetrapoda]]   
|1={{clade
   |1={{clade
      |1=''[[Eucritta melanolimnetes]]''
      |2=[[Temnospondyli]]}}
   |2={{clade
      |1=''[[Caerorhachis bairdi]]''
      |2={{clade
         |1={{clade
            |1=''[[Eoherpeton watsoni]]''
            |label2='''Embolomeri'''
            |2={{clade
               |1=''[[Proterogyrinus scheelei]]''
               |2={{clade
                  |1=''[[Archeria crassidisca]]''
                  |2=''[[Pholiderpeton scutigerum]]''
                  |3={{clade
                     |1=''[[Anthracosaurus russelli]]''
                     |2=''[[Eogyrinus|Pholiderpeton (Eogyrinus) attheyi]]''}} }} }} }}
         |2={{clade
            |1=[[Gephyrostegidae]]
            |2={{clade
               |1=''[[Solenodonsaurus janenschi]]''
               |2={{clade
                  |1=[[Seymouriamorpha]]
                  |2={{clade
                     |1=[[Lepospondyli]]
                     |2={{clade
                        |1=[[Diadectomorpha]]
                        |2=[[Amniota]]
}} }} }} }} }} }} }} }} }}

==Genera==
{| class="wikitable mw-collapsible" align="center" width="100%"
|colspan=6, style="text-align: center"|<strong>List of genera</strong>
|-
! Name
! Year
! Age
! Location
! Notes
! Images
|-
|''[[Anthracosaurus]]''
| [[1863 in paleontology|1863]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Westphalian (stage)|Westphalian]] A-B)
| {{flag|United Kingdom}} ({{flag|Scotland}})
| The namesake of [[Anthracosauria]], possessed a small number of large fangs compared to other embolomeres
|[[File:Anthracosaurus_russeli12DB.jpg|200px]]
|-
|''[[Archeria (animal)|Archeria]]''
| [[1918 in paleontology|1918]]
| [[Early Permian]]
| {{flag|United States}} ({{flag|Texas}})
| A common, late-surviving member of the group, sometimes considered a species of ''Cricotus''
|[[File:Cricotus_crassidens.JPG|200px]]
|-
|''[[Aversor]]''
| [[1985 in paleontology|1985]]
| [[Early Permian]] (Ufimian)
| {{flag|Russia}}
| Supposedly the latest surviving eogyrinid, but very poorly known
|
|-
|''[[Calligenethlon]]''
| [[1934 in paleontology|1934]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Bashkirian]])
| {{flag|Canada}} ({{flag|Nova Scotia}})
| The largest named tetrapod preserved inside lycopod tree stumps in the [[Joggins]] Fossil Cliffs
|
|-
|''[[Cricotus]]''
| [[1875 in paleontology|1875]]
| [[Pennsylvanian (geology)|Pennsylvanian]]
| {{flag|United States}} ({{flag|Illinois}})
| Responsible for the identification of Embolomeri as a unique order of tetrapods, although its history is convoluted and its taxonomic validity is questionable
|
|-
|''[[Carbonoherpeton]]''
| [[1985 in paleontology|1985]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Westphalian (stage)|Westphalian]] D)
| {{flag|Canada}} ({{flag|Nova Scotia}})
| A lightly built member of the group with characteristics of both archeriids and eogyrinids
|
|-
|''[[Diplovertebron]]''
| [[1879 in paleontology|1879]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Moscovian (Carboniferous)|Moscovian]])
| {{flag|Czech Republic}}
| A small member of the group sometimes confused with ''[[Gephyrostegus]]''
| [[File:Diplovertebron_BW.jpg|200px]]
|-
|''[[Eobaphetes]]''
| [[1916 in paleontology|1916]]
| [[Pennsylvanian (geology)|Pennsylvanian]]
| {{flag|United States}} ({{flag|Kansas}})
| A possible relative of ''Anthracosaurus'', originally named "''Erpetosuchus''" until it was determined that the name was preoccupied by a [[Erpetosuchus|Triassic reptile]].
|
|-
|''[[Eogyrinus]]''
| [[1926 in paleontology|1926]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Westphalian (stage)|Westphalian]] B)
| {{flag|United Kingdom}} ({{flag|England}})
| One of the largest and most well-known of the eogyrinids, although sometimes synonymized with ''Pholiderpeton''
| [[File:Eogyrinus_by_Abelov2014.jpg|200px]]
|-
|''[[Eoherpeton]]''
| [[1975 in paleontology|1975]]
| [[Mississippian (geology)|Mississippian]]-[[Pennsylvanian (geology)|Pennsylvanian]] ([[Visean]]-[[Bashkirian]])
| {{flag|United Kingdom}} ({{flag|Scotland}})
| One of the oldest and most basal members of the group (if it even counts as part of it), without vertebrae that were not fully embolomerous
| [[File:Eoherpeton NT.jpg|200px]]
|-
|''[[Leptophractus]]''
| [[1873 in paleontology|1873]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Westphalian (stage)|Westphalian]] D)
| {{flag|United States}} ({{flag|Ohio}})
| Known from a skull found at the Linton Diamond Mine
| 
|-
|''[[Neopteroplax]]''
| [[1963 in paleontology|1963]]
| [[Pennsylvanian (geology)|Pennsylvanian]]
| {{flag|United States}} ({{flag|Ohio}})
| One of the largest Carboniferous limbed vertebrates known from North America
| [[File:Neopteroplax conemaughensis (fossil amphibian) (Birmingham Shale, Upper Pennsylvanian; Bloomingdale, Ohio, USA) 1 (49761151626).jpg|200px]]
|-
|''[[Palaeoherpeton]]''
| [[1970 in paleontology|1970]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Westphalian (stage)|Westphalian]] A-B)
| {{flag|United Kingdom}} ({{flag|Scotland}})
| An eogyrinid known as ''Palaeogyrinus'' from 1926 to 1970, until it was determined that this name was occupied by a genus of [[beetle]]s
| 
|-
|
''[[Papposaurus]]''
| [[1914 in paleontology|1914]]
| [[Mississippian (geology)|Mississippian]]-[[Pennsylvanian (geology)|Pennsylvanian]] ([[Namurian]])
| {{flag|United Kingdom}} ({{flag|Scotland}})
| Known from a femur, may have been a relative of ''Proterogyrinus''
| 
|-
|''[[Pholiderpeton]]''
| [[1869 in paleontology|1869]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Westphalian (stage)|Westphalian]] A-B)
| {{flag|United Kingdom}} ({{flag|England}}, {{flag|Scotland}})
| An eogyrinid similar to ''Eogyrinus'' which would take priority if the two were synonymized
| [[File:Pholiderpeton NT.jpg|200px]]
|-
|''[[Proterogyrinus]]''
| [[1970 in paleontology|1970]]
| [[Mississippian (geology)|Mississippian]] ([[Serpukhovian]])
| {{flag|United States}} ({{flag|West Virginia}}), {{flag|United Kingdom}} ({{flag|Scotland}})
| An early member of the group possessing robust limbs but lacking certain adaptations of later members of the group
| [[File:Proterogyrinus DB.jpg|200px]]
|-
|''[[Pteroplax]]''
| [[1868 in paleontology|1868]]
| [[Pennsylvanian (geology)|Pennsylvanian]] ([[Westphalian (stage)|Westphalian]] B)
| {{flag|United Kingdom}} ({{flag|England}})
| Poorly known despite being among the first embolomeres to be described
| [[File:Pteroplax DB.jpg|200px]]
|-
|''[[Seroherpeton]]''
| [[2020 in paleontology|2020]]
| [[Late Permian]] ([[Wuchiapingian]])
| {{flag|China}}
| The youngest known embolomere
|
|-
|''[[Spondylerpeton]]''
| [[1912 in paleontology|1912]]
| [[Pennsylvanian (geology)|Pennsylvanian]]
| {{flag|United States}} ({{flag|Illinois}})
| A close relative of ''Cricotus'' known from vertebrae found at the [[Mazon Creek fossil beds]]
|
|-
|}

==References==
{{Reflist}}

{{Tetrapodomorpha|St.}}
{{Reptiliomorpha}}
{{Taxonbar|from=Q136529}}

[[Category:Embolomeri| ]]
[[Category:Mississippian first appearances]]
[[Category: Permian extinctions]]
[[Category:Taxa named by Edward Drinker Cope]]
[[Category:Tetrapodomorph orders]]