[go: up one dir, main page]
Jump to content

Stereognathus: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
moved image into taxobox
Citation bot (talk | contribs)
Bots
5,317,734 edits
m Removed parameters. | You can use this bot yourself. Report bugs here. | User-activated.
Line 17: Line 17:
}}
}}


'''''Stereognathus''''' is an extinct genus of [[Tritylodontidae|tritylodontid]] [[cynodont]]s from the [[Middle Jurassic]] of the [[United Kingdom]].<ref name="FossilworksStereognathus">[http://fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=39216 Fossilworks. "Stereognathus." Retrieved from]</ref> There is a single named species: ''S. ooliticus'', named after the [[Great Oolite]] deposits of England. A second species, ''S. hebridicus'', was named after the [[Hebrides]] in Scotland, where it was found; it was synonymized with ''S. ooliticus'' in 2017.<ref name="2017lump">{{cite journal | last1 = Panciroli | first1 = E. | last2 = Walsh | first2 = S. | last3 = Fraser | first3 = N.C. | last4 = Brusatte | first4 = S.L. | last5 = Corfe | first5 = I. | title = A reassessment of the postcanine dentition and systematics of the tritylodontid ''Stereognathus'' (Cynodontia, Tritylodontidae, Mammaliamorpha), from the Middle Jurassic of the United Kingdom | journal = Journal of Vertebrate Paleontology |volume=37 |issue=5 | page = e1351448 | date = 2017 | doi = 10.1080/02724634.2017.1351448 | url = http://www.tandfonline.com/doi/full/10.1080/02724634.2017.1351448}}</ref>
'''''Stereognathus''''' is an extinct genus of [[Tritylodontidae|tritylodontid]] [[cynodont]]s from the [[Middle Jurassic]] of the [[United Kingdom]].<ref name="FossilworksStereognathus">[http://fossilworks.org/cgi-bin/bridge.pl?a=taxonInfo&taxon_no=39216 Fossilworks. "Stereognathus." Retrieved from]</ref> There is a single named species: ''S. ooliticus'', named after the [[Great Oolite]] deposits of England. A second species, ''S. hebridicus'', was named after the [[Hebrides]] in Scotland, where it was found; it was synonymized with ''S. ooliticus'' in 2017.<ref name="2017lump">{{cite journal | last1 = Panciroli | first1 = E. | last2 = Walsh | first2 = S. | last3 = Fraser | first3 = N.C. | last4 = Brusatte | first4 = S.L. | last5 = Corfe | first5 = I. | title = A reassessment of the postcanine dentition and systematics of the tritylodontid ''Stereognathus'' (Cynodontia, Tritylodontidae, Mammaliamorpha), from the Middle Jurassic of the United Kingdom | journal = Journal of Vertebrate Paleontology |volume=37 |issue=5 | page = e1351448 | date = 2017 | doi = 10.1080/02724634.2017.1351448 }}</ref>


==Discovery and naming==
==Discovery and naming==
Line 24: Line 24:
Despite being the first tritylodontid genus found and named, ''Stereognathus'' remains poorly represented, being known mainly from isolated molar teeth. There is, however, one holotype fragment of maxilla with three damaged molars, and a second fragment of maxilla with four sets of molar roots.
Despite being the first tritylodontid genus found and named, ''Stereognathus'' remains poorly represented, being known mainly from isolated molar teeth. There is, however, one holotype fragment of maxilla with three damaged molars, and a second fragment of maxilla with four sets of molar roots.


In 2017, Elsa Panciroli and colleagues found no points of variance between the anatomy of ''S. ooliticus'' and ''S. hebridicus'', accounting for changes with growth, which makes ''S. hebridicus'' a [[synonym (taxonomy)|junior synonym]] of ''S. ooliticus''.<ref name="2017lump"/> Also in 2017, Alexander Averianov and colleagues considered species of ''[[Polistodon]]'', ''[[Xenocretosuchus]]'', and ''[[Montirictus]]'' to be within the genus ''Stereognathus''; they also retained ''S. hebridicus'' as a separate species.<ref name="averianov2017">{{cite journal |first1=A.O. |last1=Averianov |first2=T. |last2=Martin |first3=A.V. |last3=Lopatin |first4=J.A. |last4=Schultz |first5=P.P. |last5=Skutschas |first6=S. |last6=Rico |first7=S.A. |last7=Krasnolutskii |year=2017 |title=A tritylodontid synapsid from the Middle Jurassic of Siberia and the taxonomy of derived tritylodontids |journal=Journal of Vertebrate Paleontology |volume=37 |issue=5 |pages=e1363767 |doi=10.1080/02724634.2017.1363767 |url=http://www.tandfonline.com/doi/full/10.1080/02724634.2017.1363767}}</ref> However, this would mean ''Stereognathus'' persisted almost unchanged for over 60 million years across the whole of Eurasia, which would be very unusual. The issue remains unresolved.
In 2017, Elsa Panciroli and colleagues found no points of variance between the anatomy of ''S. ooliticus'' and ''S. hebridicus'', accounting for changes with growth, which makes ''S. hebridicus'' a [[synonym (taxonomy)|junior synonym]] of ''S. ooliticus''.<ref name="2017lump"/> Also in 2017, Alexander Averianov and colleagues considered species of ''[[Polistodon]]'', ''[[Xenocretosuchus]]'', and ''[[Montirictus]]'' to be within the genus ''Stereognathus''; they also retained ''S. hebridicus'' as a separate species.<ref name="averianov2017">{{cite journal |first1=A.O. |last1=Averianov |first2=T. |last2=Martin |first3=A.V. |last3=Lopatin |first4=J.A. |last4=Schultz |first5=P.P. |last5=Skutschas |first6=S. |last6=Rico |first7=S.A. |last7=Krasnolutskii |year=2017 |title=A tritylodontid synapsid from the Middle Jurassic of Siberia and the taxonomy of derived tritylodontids |journal=Journal of Vertebrate Paleontology |volume=37 |issue=5 |pages=e1363767 |doi=10.1080/02724634.2017.1363767 }}</ref> However, this would mean ''Stereognathus'' persisted almost unchanged for over 60 million years across the whole of Eurasia, which would be very unusual. The issue remains unresolved.


==References==
==References==

Revision as of 17:29, 10 January 2019

Stereognathus
Temporal range: Bathonian-Barremian?, 167.7–165.7 Ma
↓
The postcanine tooth of Stereognathus ooliticus, from Owen 1857.
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Synapsida
Clade: Therapsida
Clade: Cynodontia
Family: †Tritylodontidae
Genus: †Stereognathus
Charlesworth, 1854
Type species
Stereognathus ooliticus
Charlesworth, 1854
Potential species
  • S. chuannanensis (He & Cai, 1984; originally Polistodon)
  • S. kolossovi (Lopatin & Agadjanian, 2008; originally Xenocretosuchus)
  • S. kuwajimaensis (Matsuoka et al., 2016; originally Montirictus)
  • S. sibiricus (Tatarinov & Mashenko, 1999; originally Xenocretosuchus)
Synonyms
  • S. hebridicus? Waldman & Savage, 1972

Stereognathus is an extinct genus of tritylodontid cynodonts from the Middle Jurassic of the United Kingdom.[1] There is a single named species: S. ooliticus, named after the Great Oolite deposits of England. A second species, S. hebridicus, was named after the Hebrides in Scotland, where it was found; it was synonymized with S. ooliticus in 2017.[2]

Discovery and naming

S. ooliticus was the first tritylodontid species ever found, being described by Charlesworth in 1855[3] and later by Sir Richard Owen.[4] In 1972, S. hebridicus was named from several postcanine teeth recovered in Bathonian age deposits on the Isle of Skye in Scotland by palaeontologists R. J. G. Savage and Michael Waldman.[5] Despite being the first tritylodontid genus found and named, Stereognathus remains poorly represented, being known mainly from isolated molar teeth. There is, however, one holotype fragment of maxilla with three damaged molars, and a second fragment of maxilla with four sets of molar roots.

In 2017, Elsa Panciroli and colleagues found no points of variance between the anatomy of S. ooliticus and S. hebridicus, accounting for changes with growth, which makes S. hebridicus a junior synonym of S. ooliticus.[2] Also in 2017, Alexander Averianov and colleagues considered species of Polistodon, Xenocretosuchus, and Montirictus to be within the genus Stereognathus; they also retained S. hebridicus as a separate species.[6] However, this would mean Stereognathus persisted almost unchanged for over 60 million years across the whole of Eurasia, which would be very unusual. The issue remains unresolved.

References

  1. ^ Fossilworks. "Stereognathus." Retrieved from
  2. ^ a b Panciroli, E.; Walsh, S.; Fraser, N.C.; Brusatte, S.L.; Corfe, I. (2017). "A reassessment of the postcanine dentition and systematics of the tritylodontid Stereognathus (Cynodontia, Tritylodontidae, Mammaliamorpha), from the Middle Jurassic of the United Kingdom". Journal of Vertebrate Paleontology. 37 (5): e1351448. doi:10.1080/02724634.2017.1351448.
  3. ^ Charlesworth, E 1855. Reprint British Association. 1854 Liverpool Abstracts, 80.
  4. ^ Owen, R 1856 On the affinity of Stereognathus ooliticus (Charlesworth) a mammal from the Oolitic slate of Stonesfield . Quarterly Journal of the Geological Society of London, 13, 1-11.
  5. ^ Waldman, M and Savage, R.J.G 1972 The first Jurassic mammal from Scotland. Journal of the Geological Society of London 128:119-125
  6. ^ Averianov, A.O.; Martin, T.; Lopatin, A.V.; Schultz, J.A.; Skutschas, P.P.; Rico, S.; Krasnolutskii, S.A. (2017). "A tritylodontid synapsid from the Middle Jurassic of Siberia and the taxonomy of derived tritylodontids". Journal of Vertebrate Paleontology. 37 (5): e1363767. doi:10.1080/02724634.2017.1363767.


Stub icon

This therapsid-related article is a stub. You can help Wikipedia by expanding it.

Retrieved from "https://en.wikipedia.org/w/index.php?title=Stereognathus&oldid=877751119"