{{Short description|Extinct genus of amphibians}} {{Automatic taxobox | fossil_range = [[Early Triassic]],<br />~{{fossil range|251.902|246.7}}{{period fossil range|Triassic|251.902|246.7}} | image = Trematosaurus brauni.JPG | image_caption = ''T. brauni'' skull | taxon = Trematosaurus | authority = [[Hermann Burmeister|Burmeister]], 1849 | subdivision_ranks = Species | subdivision = *{{extinct}}'''''T. brauni''''' <small>Burmeister, 1849 ([[type species|type]])</small> *{{extinct}}'''''T. thuringiensis''''' <small>Werneburg, 1993</small> *{{extinct}}'''''T. galae''''' <small>Novikov, 2010</small> }}
'''''Trematosaurus''''' is an [[extinct]] [[genus]] of [[Trematosauridae|trematosaurid]] [[temnospondyl]] [[amphibian]] found in [[Germany]] and [[Russia]].<ref name=Novikov>{{Cite journal |author=I. V. Novikov |year=2010 |title=New data on trematosauroid labyrinthodonts of Eastern Europe: 2. ''Trematosaurus galae'' sp. nov.: Cranial morphology|journal=Paleontological Journal |volume=44 |issue=4 |pages=457–467 |doi=10.1134/S003103011004012X |bibcode=2010PalJ...44..457N |s2cid=85353510 }}</ref> It was first named by Hermann Burmeister in 1849 and the type species is ''Trematosaurus brauni''.<ref name=Novikov/><ref name=":0">{{Cite book |last=Burmeister |first=Hermann |title=Die Labyrinthodonten aus dem bunten Sandstein von Bernburg: zoologisch geschildert / von Hermann Burmeister. |date=1849 |publisher=G. Reimer |location=Berlin |doi=10.5962/bhl.title.5493 }}</ref>
== History of study == ''Trematosaurus'' was one of the first temnospondyls to be described. The type locality, called Merkel's Quarry, is in east-central [[Germany]] at [[Bernburg an der Saale]] within the Bausandstein ([[Olenekian]]) and was collected for several decades from the 1840s into the early 20th century, producing extensive cranial remains, although the majority of these are preserved as internal molds (steinkerns) or natural molds. The name ''Trematosaurus'' was in fact coined in 1842 by Carl von Braun, a frequent collector who used the Greek suffix ''trema'' ('hole') in reference to the [[pineal foramen]] to form the generic epithet, but as he provided no formal description, the name was not considered valid until the work of Burmeister,<ref name=":0" /> who named the type species after Braun. Burmeister's work was largely reconstructive and frequently omitted references to which specimens were being described, and as a result, it remains unknown which specimens exactly were covered in his description. This was remedied by subsequent workers who provided specimen illustrations for material reposited at numerous museums across Europe.<ref>{{Cite journal |last=Fraas |first=Eberhaard |date=1913 |title=Neue Labyrinthodonten aus der schwäbischen Trias |journal=Palaeontographica |volume=60 |pages=275–294}}</ref><ref>{{Cite journal |last=Drevermann |first=Friedrich E. |date=1914 |title=Über einen Schädel von Trematosaurus brauni Burmeister |journal=Centralblatt für Mineralogie, Geologie und Paläontologie |volume=1914 |pages=627–628}}</ref><ref>{{Cite journal |last=Drevermann |first=Friedrich E. |date=1920 |title=Über einen Schädel von Trematosaurus brauni Burmeister |url=http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/year/2009/docId/6680 |journal=Senckenbergiana |volume=2 |pages=83–110}}</ref><ref name=":1">{{Cite journal |last=Watson |first=David Meredith Seares |date=1919 |title=I. The structure, evolution and origin of the amphibia. - The "orders' rachitomi and stereospondyli |journal=Philosophical Transactions of the Royal Society of London. Series B, Containing Papers of a Biological Character |volume=209 |issue=360–371 |pages=1–73 |doi=10.1098/rstb.1920.0001 |issn=0264-3960|doi-access=free }}</ref><ref>{{Cite journal |last=von Huene |first=Friedrich |date=1921 |title=Über einen wohlerhaltenen Gaumen von Trematosaurus brauni. |journal=Centralblatt für Mineralogie, Geologie und Paläontologie |volume=1921 |pages=502–504}}</ref> However, the complete osteology and ontogeny of this taxon remained poorly documented until the work of Schoch (2019).<ref name=":2">{{Cite journal |last=Schoch |first=Rainer R. |date=2019-05-24 |title=Osteology of the temnospondyl ''Trematosaurus brauni'' Burmeister, 1849 from the Middle Buntsandstein of Bernburg, Germany |journal=Palaeodiversity |volume=12 |issue=1 |page=41 |doi=10.18476/pale.v12.a4 |s2cid=181970743 |issn=1867-6294|doi-access=free }}</ref>
Two other species were described from equivalent horizons in [[Thuringia]], ''T. fuchsi'' and ''T. thuringiensis''.<ref>{{Cite journal |last=Seidlitz |first=Wilfred von. |date=1920 |title=Trematosaurus fuchsi, ein Labyrinthodont aus dem thüringischen Buntsandstein |journal=Palaeontographica |volume=63 |pages=87–96}}</ref><ref>{{Cite journal |last=Werneburg |first=Ralf |date=1993 |title=Trematosaurus (Amphibia) aus dem Mittleren Buntsandstein (Untertrias) von Thüringen |journal=Er- öffentlichungen des Naturhistorischen Museums |volume=7/8 |pages=17–29}}</ref> ''Trematosaurus fuchsi'' is widely regarded as a junior synonym of ''T. brauni,'' while ''T. thuringiensis'' is tentatively considered to be valid with the caveat that poor preservation of the single specimen may account for some of the purported differences.<ref name=":3">{{Cite book |last1=Schoch |first1=Rainer R. |title=Handbuch der Paläoherpetologie Part 3B. Stereospondyli |last2=Milner |first2=Andrew R. |publisher=Verlag Dr. Friedrich Pfeil |year=2000 |isbn=978-3-931516-26-0 |location=Stuttgart |pages=1–220 |oclc=580976}}</ref><ref name="Novikov" /> ''Trematosaurus madagascariensis'' was synonymized with ''[[Tertremoides|Tertremoides ambilobensis]]'' from the same horizon in [[Madagascar]] by Schoch & Milner (2000), with the species epithet of the former (named first) taking precedence by priority and the genus epithet of the latter taking precedence by distinction from ''Trematosaurus''.<ref name=":3" /> ''Trematosaurus sobeyi'' from [[Cynognathus Assemblage Zone]] of [[South Africa]] was placed in the novel genus ''[[Trematosuchus]]'' by Watson (1919).<ref name=":1" /> ''Trematosaurus kannemeyeri'' from the same zone is thought to belong to ''[[Aphaneramma]]'',<ref name="Novikov" /><ref name=":3" /> but other workers do not consider it to be diagnostic and thus to be invalid.<ref>{{Cite journal |last1=Fortuny |first1=Josep |last2=Gastou |first2=Stéphanie |last3=Escuillié |first3=François |last4=Ranivoharimanana |first4=Lovasoa |last5=Steyer |first5=J.-Sébastien |date=2017-06-29 |title=A new extreme longirostrine temnospondyl from the Triassic of Madagascar: phylogenetic and palaeobiogeographical implications for trematosaurids |journal=Journal of Systematic Palaeontology |volume=16 |issue=8 |pages=675–688 |doi=10.1080/14772019.2017.1335805 |s2cid=134191156 |issn=1477-2019|url=https://figshare.com/articles/dataset/A_new_extreme_longirostrine_temnospondyl_from_the_Triassic_of_Madagascar_phylogenetic_and_palaeobiogeographical_implications_for_trematosaurids/5155366 |url-access=subscription }}</ref><ref>{{Cite journal |last1=Hancox |first1=P.J. |last2=Neveling |first2=J. |last3=Rubidge |first3=B.S. |date=2020-06-01 |title=Biostratigraphy of the Cynognathus Assemblage Zone (Beaufort Group, Karoo Supergroup), South Africa |journal=South African Journal of Geology |volume=123 |issue=2 |pages=217–238 |doi=10.25131/sajg.123.0016 |bibcode=2020SAJG..123..217H |s2cid=225828531 |issn=1996-8590}}</ref> ''Trematosaurus yakovlevi'' from Russia was placed in the novel genus ''[[Thoosuchus]]'' by Efremov (1940).<ref>{{Cite journal |last=Efremov |first=Ivan A. |date=1940 |title=Preliminary description of the new Permian and Triassic Tetrapoda from U.S.S.R. |journal=Trudy Paleontologicheskogo Instituta |language=Russian |volume=10 |pages=1–140}}</ref> ''Trematosaurus weidenbaumi'' was first removed to ''Thoosuchus'' and then placed in the novel genus ''[[Angusaurus]]'' by Getmanov (1989).<ref>{{Cite journal |last=Getmanov |first=S. N. |date=1989 |title=Triassic amphibians of the East European platform (family Benthosuchidae Efremov). |journal=Trudy Paleontologicheskogo Instituta |volume=236 |pages=1–102}}</ref> Various reports of ''Trematosaurus'' sp. from [[Russia]] belong to ''[[Inflectosaurus]]'',<ref name=":3" /> but ''Trematosaurus galae'' is a recently described Russian species that remains valid to date.<ref name="Novikov" />
== Description == [[Image:Trematosaurus1DB.jpg|thumb|left|''T. brauni'']]The overwhelming majority of specimens of ''T. brauni'' are partial to complete skulls, with 75 such specimens known (size range from 10.9 to 41 cm in length). Postcrania are restricted to the clavicle and interclavicle, two large plate-like elements of the pectoral girdle. In part, this relates to the occurrence of other large [[Stereospondyli|stereospondyls]] at the type locality such as the [[Capitosauria|capitosaur]] ''[[Parotosuchus|Parotosuchus nasutus]]'', but postcrania are generally scarce, which may be due to either collection bias or taphonomic bias. Therefore, all diagnostic features of ''T. brauni'' are based on the skull. [[Autapomorphy|Autapomorphies]] include (1) temporal sulcus of lateral line with two portions, (2) occipital sulcus continuous, (3) pre-orbital region slightly shorter than half skull length (0.43–0.49), and (4) interorbital distance wide (interorbital distance/ skull length: 0.15–0.2).<ref name=":2" /> The description is based only on referred specimens, as no [[holotype]] was ever designated and the [[syntype]]s described by Burmeister cannot be identified based on the scant details of his description; however, because they may exist, either within public or private collections, no [[neotype]] designation is warranted at present. ''Trematosaurus galae'' differs from ''T. brauni'' in (1) presence of well-pronounced lacrimal and zygomatic flexures of canals of the lateral line, (2) connection of both branches of the temporal groove at the ossification center of the supratemporal, and (3) in the presence of a supplementary groove (sulcus buccalis transversus) on the squamosal.<ref name="Novikov" /> The more questionably valid ''T. thuringiensis'' differs only in having larger orbits and a narrower skull table than the type species.<ref name=":3" />
Given the large sample size of ''T. brauni'', its ontogeny can be characterized, exhibiting features such as decreased orbit size and skull width but not other features such as broadening of the interorbital region or increased preorbital length, which occur in other temnospondyls.<ref name=":2" /> Observations of more fragmentary material of ''T. galae'' indicate that specifically the prenarial region and the postorbital regions become longer, along with increased development of other features such as the basioccipital and ornamentation on the parasphenoid replacing a shagreen of denticles.
==Classification== Below is a cladogram from Steyer (2002) showing the [[phylogenetic]] relationships of trematosaurids:<ref name=SJS02>{{cite journal |last=Steyer |first=J. S. |year=2002 |title=The first articulated trematosaur 'amphibian' from the Lower Triassic of Madagascar: implications for the phylogeny of the group |journal=Palaeontology |volume=45 |issue=4 |pages=771–793 |doi=10.1111/1475-4983.00260|bibcode=2002Palgy..45..771S |s2cid=83515233 }}</ref> {{clade| style=font-size:100%;line-height:85% |label1=[[Trematosauridae]] |1={{clade |label1=[[Trematosaurinae]] |1={{clade |1={{clade |1=''[[Tertrema]]'' |2={{clade |1=''[[Lyrocephaliscus]]'' |2=''[[Platystega]]''}} }} |2={{clade |1=''[[Luzocephalus]]'' |2={{clade |1='''''Trematosaurus''''' |2=''[[Trematosuchus]]''}} }} }} |label2=[[Lonchorhynchinae]] |2={{clade |1=''[[Aphaneramma]]'' |2={{clade |1=''[[Erythrobatrachus]]'' |2=''[[Cosgriffius]]'' |3={{clade |1=''[[Stoschiosaurus]]'' |2=''[[Wantzosaurus]]''}} }} }} }} }}
''Trematosaurus'' in a cladogram after Novikov (2018) with only Early Triassic Eastern Europe taxa included:<ref name=Novikov2018>{{cite book|author=Novikov A.V.|year=2018|url=https://new.ras.ru/upload/iblock/7de/j85vtubof3mlf81izrqq9u9oh9eb5lrh.pdf|title=Early Triassic amphibians of Eastern Europe: evolution of dominant groups and peculiarities of changing communities|publisher=Moscow: RAS|page=138|lang=ru|isbn=978-5-906906-71-7}} {{cite web|url=https://new.ras.ru/upload/iblock/7de/j85vtubof3mlf81izrqq9u9oh9eb5lrh.pdf |title=Archive copy |date=December 8, 2023 |archive-url=https://web.archive.org/web/20231208092959/https://new.ras.ru/upload/iblock/7de/j85vtubof3mlf81izrqq9u9oh9eb5lrh.pdf |archive-date=2023-12-08 }}</ref>
{{clade |label1=[[Trematosauridae]] |1={{clade |1=''[[Prothoosuchus]]'' |2={{clade |1=''[[Thoosuchus]]'' |2={{clade |1=''[[Trematotegmen]]'' |2={{clade |1=''[[Angusaurus]]'' |2={{clade |1=''[[Inflectosaurus]]'' |2='''''Trematosaurus''''' }} }} }} }} }} }}
==References== {{Portal|Paleontology}} <references /> {{Trematosauria|T.}} {{Taxonbar|from=Q3776858}}
[[Category:Triassic temnospondyls of Europe]] [[Category:Trematosaurines]] [[Category:Taxa named by Hermann Burmeister]] [[Category:Prehistoric amphibian genera]]