Discosauriscus
| Discosauriscus Temporal range: Early Permian
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| Discosauriscus austriacus | |
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| Class: | Amphibia sensu lato
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| Genus: | Discosauriscus Kuhn, 1933
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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
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
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ Carroll, R.L. 1988. Vertebrate Paleontology and Evolution, pp 176. WH Freeman and Company, New York ISBN 0-7167-1822-7
- ^ 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/
- ^ Sanchez S, Klembara J, Castanet J, Steyer JS. 2008. Salamander-like development in a seymouriamorph revealed by palaeohistology. Biology Letters 4: 411–414.
- ^ 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.
- ^ dinosaurier-news - Discosauriscus: Ein Amphibium aus der Permzeit
- ^ Klembara, J, Electroreceptors in the Lower Permian tetrapod Discosauriscus austriacus,Palaeontology, Vol 37, part 3, (1994)
