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==Characteristics==
==Characteristics==
Discosauriscids were long thought to be known from [[larva]]l or [[neotenic]] forms,<ref>Carroll, R.L. 1988. Vertebrate Paleontology and Evolution, pp 176. WH Freeman and Company, New York ISBN 0-7167-1822-7</ref> and three ontogenetic stages had been distinguished.<ref name="tolweb.org">Klembara, Jozef. 1996. Discosauriscus. Version 1 January 1996. http://tolweb.org/Discosauriscus/17544/1996.01.01 in The Tree of Life Web Project, http://tolweb.org/</ref> However, more recent studies concluded that some subadult, probably terrestrial specimens were known,<ref>{{cite journal | last1 = Sanchez | first1 = S | last2 = Klembara | first2 = J | last3 = Castanet | first3 = J | last4 = Steyer | first4 = JS | year = 2008 | title = Salamander-like development in a seymouriamorph revealed by palaeohistology | url = | journal = Biology Letters | volume = 4 | issue = | pages = 411–414 | doi=10.1098/rsbl.2008.0159}}</ref><ref name=K08>{{cite journal |last=Kriloff |first=A. |author2=Germain, D. |author3= Canoville, A. |author4= Vincent, P. |author5= Sache, M. |author6= Laurin, M. |year=2008 |title=Evolution of bone microanatomy of the tetrapod tibia and its use in palaeobiological inference |journal=Journal of Evolutionary Biology |volume=21 |issue=3 |pages=807–826 |doi=10.1111/j.1420-9101.2008.01512.x |pmid=18312321}}</ref> so the case for neoteny in this taxon is not as well-supported as once thought. ''Discosauriscus'' had wide jaws with sharp teeth, short limbs and relatively long tail.<ref>[http://dinosaurier-news.blog.de/2005/08/20/discosauriscus_ein_amphibium_aus_der_per dinosaurier-news - Discosauriscus: Ein Amphibium aus der Permzeit<!-- Bot generated title -->] {{webarchive |url=https://web.archive.org/web/20130713050703/http://dinosaurier-news.blog.de/2005/08/20/discosauriscus_ein_amphibium_aus_der_per |date=13 July 2013 }}</ref> The [[phalangeal formula]] was 2-3-4-5-3 for both hind- and forelimbs. The body was covered with rounded scales with concentric rings, and a well-preserved lateral-line system has been described.<ref name="tolweb.org"/>
Discosauriscids were long thought to be known from [[larva]]l or [[neotenic]] forms,<ref>Carroll, R.L. 1988. Vertebrate Paleontology and Evolution, pp 176. WH Freeman and Company, New York ISBN 0-7167-1822-7</ref> and three ontogenetic stages had been distinguished.<ref name="tolweb.org">Klembara, Jozef. 1996. Discosauriscus. Version 1 January 1996. http://tolweb.org/Discosauriscus/17544/1996.01.01 in The Tree of Life Web Project, http://tolweb.org/</ref> However, more recent studies concluded that some subadult, probably terrestrial specimens were known,<ref>{{cite journal | last1 = Sanchez | first1 = S | last2 = Klembara | first2 = J | last3 = Castanet | first3 = J | last4 = Steyer | first4 = JS | year = 2008 | title = Salamander-like development in a seymouriamorph revealed by palaeohistology | journal = Biology Letters | volume = 4 | issue = | pages = 411–414 | doi=10.1098/rsbl.2008.0159 | pmid=18460423 | pmc=2610144}}</ref><ref name=K08>{{cite journal |last=Kriloff |first=A. |author2=Germain, D. |author3= Canoville, A. |author4= Vincent, P. |author5= Sache, M. |author6= Laurin, M. |year=2008 |title=Evolution of bone microanatomy of the tetrapod tibia and its use in palaeobiological inference |journal=Journal of Evolutionary Biology |volume=21 |issue=3 |pages=807–826 |doi=10.1111/j.1420-9101.2008.01512.x |pmid=18312321}}</ref> so the case for neoteny in this taxon is not as well-supported as once thought. ''Discosauriscus'' had wide jaws with sharp teeth, short limbs and relatively long tail.<ref>[http://dinosaurier-news.blog.de/2005/08/20/discosauriscus_ein_amphibium_aus_der_per dinosaurier-news - Discosauriscus: Ein Amphibium aus der Permzeit<!-- Bot generated title -->] {{webarchive |url=https://web.archive.org/web/20130713050703/http://dinosaurier-news.blog.de/2005/08/20/discosauriscus_ein_amphibium_aus_der_per |date=13 July 2013 }}</ref> The [[phalangeal formula]] was 2-3-4-5-3 for both hind- and forelimbs. The body was covered with rounded scales with concentric rings, and a well-preserved lateral-line system has been described.<ref name="tolweb.org"/>


''Discosauriscus'' may have had electroreceptive organs.<ref>Klembara, J, Electroreceptors in the Lower Permian tetrapod Discosauriscus austriacus, Palaeontology, Vol 37, part 3, (1994)</ref>
''Discosauriscus'' may have had electroreceptive organs.<ref>Klembara, J, Electroreceptors in the Lower Permian tetrapod Discosauriscus austriacus, Palaeontology, Vol 37, part 3, (1994)</ref>

Revision as of 09:48, 12 March 2017

Discosauriscus
Temporal range: Early Permian
Discosauriscus austriacus
Scientific classification
Kingdom:
Phylum:
Class:
Amphibia sensu lato
Order:
Family:
Genus:
Discosauriscus

Kuhn, 1933
Species
  • D. austriacus (Makowsky, 1876)
  • D. pulcherrimus (Fritsch, 1879) (type)
Synonyms
  • Letoverpeton Spinar, 1952

Discosauriscus was a small stegocephalian that has long been considered a reptiliomorph,[1] but that some recent analyses place among stem-tetrapods.[2][3][4] It lived in what is now Central and Western Europe in the Early Permian Period. Its best fossils have been found in Boskovice Furrow, in the Czech Republic.

Classification

File:Discosauriscus BW.jpg
D. austriacus restoration
Fossil in Vienna

Discosauriscus belongs in alternative classifications to the order Anthracosauria or Seymouriamorpha, and is the type genus of the family Discosauriscidae. Currently recognised are two valid species - Discosauriscus austriacus and Discosauriscus pulcherrimus. Letoverpeton is a junior synonym of Discosauriscus.[5]

Characteristics

Discosauriscids were long thought to be known from larval or neotenic forms,[6] and three ontogenetic stages had been distinguished.[7] However, more recent studies concluded that some subadult, probably terrestrial specimens were known,[8][9] so the case for neoteny in this taxon is not as well-supported as once thought. Discosauriscus had wide jaws with sharp teeth, short limbs and relatively long tail.[10] The phalangeal formula was 2-3-4-5-3 for both hind- and forelimbs. The body was covered with rounded scales with concentric rings, and a well-preserved lateral-line system has been described.[7]

Discosauriscus may have had electroreceptive organs.[11]

References

  1. ^ Panchen, A. L. and Smithson, T. R. 1988. The relationships of the earliest tetrapods. Pp. 1-32 in Benton, M. J. (ed), The Phylogeny and Classification of the Tetrapods, Volume 1: Amphibians, Reptiles, Birds. Clarendon Press, Oxford.
  2. ^ Laurin M. (1998): The importance of global parsimony and historical bias in understanding tetrapod evolution. Part I-systematics, middle ear evolution, and jaw suspension. Annales des Sciences Naturelles, Zoologie, Paris, 13e Series 19: pp 1-42.
  3. ^ Vallin, G; Laurin, M (2004). "Cranial morphology and affinities of Microbrachis, and a reappraisal of the phylogeny and lifestyle of the first amphibians". Journal of Vertebrate Paleontology. 24: 56–72. doi:10.1671/5.1.
  4. ^ Marjanović, D.; Laurin, M. (2009). "The origin(s) of modern amphibians: a commentary". Evolutionary Biology. 36 (3): 336–338. doi:10.1007/s11692-009-9065-8.
  5. ^ Klembara, Jozef (1997). "The cranial anatomy of Discosauriscus Kuhn, a seymouriamorph tetrapod from the Lower Permian of the Boskovice Furrow (Czech Republic)". Philosophical Transactions of the Royal Society of London, Series B. 352: 257–302. Bibcode:1997RSPTB.352..257K. doi:10.1098/rstb.1997.0021. PMC 1691931.
  6. ^ Carroll, R.L. 1988. Vertebrate Paleontology and Evolution, pp 176. WH Freeman and Company, New York ISBN 0-7167-1822-7
  7. ^ a b Klembara, Jozef. 1996. Discosauriscus. Version 1 January 1996. http://tolweb.org/Discosauriscus/17544/1996.01.01 in The Tree of Life Web Project, http://tolweb.org/
  8. ^ Sanchez, S; Klembara, J; Castanet, J; Steyer, JS (2008). "Salamander-like development in a seymouriamorph revealed by palaeohistology". Biology Letters. 4: 411–414. doi:10.1098/rsbl.2008.0159. PMC 2610144. PMID 18460423.
  9. ^ Kriloff, A.; Germain, D.; Canoville, A.; Vincent, P.; Sache, M.; Laurin, M. (2008). "Evolution of bone microanatomy of the tetrapod tibia and its use in palaeobiological inference". Journal of Evolutionary Biology. 21 (3): 807–826. doi:10.1111/j.1420-9101.2008.01512.x. PMID 18312321.
  10. ^ dinosaurier-news - Discosauriscus: Ein Amphibium aus der Permzeit Archived 13 July 2013 at the Wayback Machine
  11. ^ Klembara, J, Electroreceptors in the Lower Permian tetrapod Discosauriscus austriacus, Palaeontology, Vol 37, part 3, (1994)