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'{{short description|Species of amphibian}} {{speciesbox | fossil_range = <br />[[Pennsylvanian (geology)|Pennsylvanian]]–[[Cisuralian]], {{fossilrange|299|278}} | image = Eryops - National Museum of Natural History - IMG 1974.JPG | image_upright = 1.1 | image_caption = Cast of a skeleton and tadpole (formerly known as ''Pelosaurus''), [[National Museum of Natural History]] | genus = Eryops | parent_authority = [[Edward Drinker Cope|Cope]], [[1877 in paleontology|1887]] | species = megacephalus | authority = Cope, 1877 }} '''''Eryops''''' {{IPAc-en|ˈ|ɛ|r|i|.|ɒ|p|s}} meaning "drawn-out face" because most of its skull was in front of its eyes ([[Greek language|Greek]] ἐρύειν, ''eryein'' = drawn-out + ὤψ, ''ops'' = face) is a [[genus]] of extinct, amphibious [[temnospondyl]]s. It contains the single species '''''Eryops megacephalus''''', the [[fossil]]s of which are found mainly in early [[Permian]] (about 295&nbsp;million years ago) rocks of the [[Red Beds of Texas and Oklahoma|Texas Red Beds]], located in [[Archer County, Texas]]. Fossils have also been found in late [[Carboniferous]] period rocks from [[New Mexico]]. Several complete [[skeleton]]s of ''Eryops'' have been found in lower Permian rocks, but [[skull]] bones and [[teeth]] are its most common fossils. == Description == [[File:Eryops1DB.jpg|left|thumb|Life restoration]] ''Eryops'' averaged a little over {{convert|1.5|-|2.0|m|ft}} long and could grow up to {{convert|3|m|ft}},<ref name=Schoch2009>{{cite journal|doi=10.1146/annurev.earth.031208.100113|title=Evolution of life cycles in early amphibians|journal=Annual Review of Earth and Planetary Sciences |volume=37 |issue=1|pages=135–162 |year=2009 |last1=Schoch |first1=Rainer R.|bibcode=2009AREPS..37..135S}}</ref> making them among the largest land animals of their time. Adults weighed about {{convert|90|kg|lbs}}. The skull was proportionately large, being broad and flat and reaching lengths of {{convert|60|cm|ft}}. It had an enormous mouth with many curved teeth like the frog. Its teeth had [[tooth enamel|enamel]] with a folded pattern, leading to its early classification as a "[[labyrinthodont]]" ("maze toothed"). The shape and cross section of ''Eryops'' teeth made them exceptionally strong and resistant to stresses.<ref name= Rinehart&lucas2013/> The palate, or roof of the mouth, contained three pairs of backward-curved fangs, and was covered in backward-pointing bony projections which would have been used to trap slippery prey once caught. This, coupled with the wide gape, suggest an inertial method of feeding, in which the animal would grasp its prey and thrust forward, forcing the prey farther back into its mouth.<ref name= Rinehart&lucas2013>{{cite journal|last1=Rinehart, L. F. |last2=Lucas, S. G. |year=2013 |title=Tooth form and function in temnospondyl amphibians: relationship of shape to applied stress |journal=New Mexico Museum of Natural History Bulletin |volume=61''' |pages=533–542 |url=http://paleo.cortland.edu/globaltriassic2/Bulletin%2061%20Final/40-Rinehart%20and%20Lucas%20(Metopo%20teeth).pdf}}</ref> The skeleton of ''Eryops'' was much more strongly built and sturdy than related temnospondyls. The limbs were especially large and strong. The [[pectoral girdle]] was highly developed, with a larger size for increased [[muscle]] attachments. Most notably, the shoulder girdle was disconnected from the skull, resulting in improved terrestrial locomotion. The crossopterygian [[cleithrum]] was retained as the [[clavicle]], and the [[interclavicle]] was well-developed, lying on the underside of the chest. In primitive forms, the two clavicles and the interclavicle could have grown ventrally in such a way as to form a broad chest plate, although such was not the case in ''Eryops''. The upper portion of the girdle had a flat scapular blade, with the [[glenoid]] cavity situated below performing as the articulation surface for the [[humerus]], while ventrally there was a large flat [[coracoid]] plate turning in toward the midline.<ref name=appendicular_eryops>{{cite journal|last1=Pawley|first1=Kat|last2=Warren|first2=Anne |year=2006 |title=The appendicular skeleton of ''Eryops megacephalus'' Cope, 1877 (Temnospondyli: Eryopoidea) from the Lower Permian of North America |journal=Journal of Paleontology |volume=80 |issue=3 |pages=561–580 |doi=10.1666/0022-3360(2006)80[561:TASOEM]2.0.CO;2 |jstor=4095151}}</ref> The [[Pelvis|pelvic]] girdle also was much larger than the simple plate found in fishes, accommodating more muscles. It extended far dorsally and was joined to the backbone by one or more specialized sacral [[rib]]s. The hind legs were somewhat specialized in that they not only supported weight, but also provided propulsion. The dorsal extension of the pelvis was the ''[[ilium (bone)|ilium]]'', while the broad ventral plate was composed of the [[pubis (bone)|pubis]] in front and the [[ischium]] behind. The three bones met at a single point in the center of the pelvic triangle, called the ''acetabulum'', providing a surface of articulation for the [[femur]].<ref name=appendicular_eryops/> The texture of ''Eryops'' skin was revealed by a fossilized "mummy" described in 1941. This mummy specimen showed that the body in life was covered in a pattern of oval bumps.<ref name=romerwitter1941>{{cite journal|last1=Romer|first1=A. S.|last2=Witter|first2=R. V. |year=1941 |title=The skin of the rachitomous amphibian ''Eryops'' |journal=American Journal of Science |volume=239 |issue=11 |pages=822–824 |doi=10.2475/ajs.239.11.822}}</ref> ==Discovery and species== [[File:Eryops megacephalus (cast) at Göteborgs Naturhistoriska Museum 2355.jpg|thumb|Cast of the skull]] ''Eryops'' is currently thought to contain only one species, ''E. megacephalus'', which means "large-headed ''Eryops''". ''E. megacephalus'' fossils have been found only in rocks dated to the early [[Permian]] period ([[Sakmarian]] age, about 295 million years ago) in the southwestern United States, primarily in the [[Admiral Formation]] of the [[Red Beds of Texas and Oklahoma|Texas Red Beds]].<ref>Gould, Stephen Jay, ed. [https://books.google.com/books?id=9DIloiBThhIC&lpg=PA94&ots=oZiPTp-IWw&dq=eryops%20archer%20county&pg=PA94#v=onepage&q=eryops%20archer%20county&f=false The Book Of Life: An Illustrated History of the Evolution of Life on Earth.] W.W. Norton: 2001, pg. 94. Retrieved August 28, 2017.</ref> During the mid-20th century, some older fossils were classified as a second species of ''Eryops'', ''E. avinoffi''. This species, known from [[Carboniferous]] period fossil found in [[Pennsylvania]], had originally been classified in the genus ''[[Glaukerpeton]]''. Beginning in the late 1950s, some scientists concluded that ''Glaukerpeton'' was too similar to ''Eyrops'' to deserve its own genus. However, later studies supported the original classification of ''Glaukerpeton'', finding that it was more primitive than ''Eryops'' and some other early temnospondyls.<ref name=werneburg&berman2012>{{cite journal|doi=10.2992/007.081.0103|title=Revision of the aquatic eryopid temnospondyl ''Glaukerpeton avinoffi'' Romer, 1952, from the Upper Pennsylvanian of North America|journal=Annals of Carnegie Museum|volume=81|pages=33–60 |year=2012|last1=Werneburg|first1=Ralf|last2=Berman|first2=David S}}</ref> Supposed ''Eryops'' fossils also found in older [[Pennsylvanian (geology)|Pennsylvanian]] epoch rocks of the [[Conemaugh Group]] in West Virginia<ref>{{cite journal| last1=Murphy |first1=James L. |year=1971 |title=Eryopsid Remains from the Conemaugh Group, Braxton County, West Virginia |journal=Southeastern Geology |volume=13 |issue=4 |pages=265–273}}</ref> also turned out to be remains of ''Glaukerpeton''.<ref name=werneburg&berman2012/> In 2005, a skull clearly belonging to ''Eryops'' was found in upper [[Pennsylvanian (geology)|Pennsylvanian]] epoch rocks of the [[El Cobre Canyon Formation]] in [[New Mexico]], representing the oldest known specimen.<ref name=werneburgetal2010a>{{cite book| last1=Werneburg |first1=R. |author2=S.G. Lucas |author3=J.W. Schneider |author4=L.F. Rinehart |year=2010 |chapter=First Pennsylvanian ''Eryops'' (Temnospondyli) and its Permian record from New Mexico |pages=129–135 |editor1=Lucas, S.G. |editor2=J.W. Schneider |editor3=J.A. Spielmann |title=Carboniferous-Permian transition in Canõn del Cobre, northern New Mexico |series=New Mexico Museum of Natural History and Science Bulletin |volume=49}}</ref> ==Paleobiology== ''Eryops'' were among the most formidable early Permian carnivores and perhaps the only ones capable of competing with the dominant [[synapsid]]s of the time, though because they were semi-aquatic, if not mostly aquatic, as suggested by long bone microanatomy,<ref name=Qu13>{{cite journal| last1=Quémeneur |first1=S. | last2=de Buffrénil |first2=V.| last3=Laurin |first3=M.|year=2013 |title=Microanatomy of the amniote femur and inference of lifestyle in limbed vertebrates |journal=Biological Journal of the Linnean Society |volume=109 |issue=3 |pages=644–655 |doi=10.1111/bij.12066 }}</ref> they probably did not come into frequent competition with synapsids.<ref>{{cite journal |last1=Van Valkenburgh, B. |last2=Jenkins, I. |year=2002 |title=Evolutionary patterns in the history of Permo-Triassic and Cenozoic synapsid predators |journal=Paleontological Society Papers |volume=8 |pages=267–288}}</ref> ''Eryops'' lived in lowland habitats in and around ponds, streams, and rivers, and the arrangement and shape of their teeth suggests that they probably ate mostly large fish and aquatic tetrapods.<ref name=Schoch2009/> The torso of ''Eryops'' was relatively stiff and the tail stout, which would have made them poor swimmers. While they probably fed on fish, adult ''Eryops'' must have spent most of their time on land.<ref name=Schoch2009/> Like other large primitive temnospondyls, ''Eryops'' would have grown slowly and gradually from aquatic larvae, but they did not go through a dramatic [[metamorphosis]] like many modern [[amphibian]]s. While adults probably lived in ponds and rivers, or may have ventured onto their banks, juvenile ''Eryops'' may have lived in swamps, which may have offered more shelter from predators.<ref name=Schoch2009/> == References == {{Reflist|30em}} {{Portal|Paleontology}} {{Euskelia|E.}} {{Taxonbar|from=Q680153}} [[Category:Carboniferous temnospondyls of North America]] [[Category:Cisuralian temnospondyls of North America]] [[Category:Pennsylvanian first appearances]] [[Category:Cisuralian genus extinctions]] [[Category:Eryopids]] [[Category:Taxa named by Edward Drinker Cope]] [[Category:Fossil taxa described in 1887]] [[Category:Prehistoric amphibian genera]]'