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Lemmysuchus

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Lemmysuchus
Temporal range: Late Jurassic, Callovian
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Holotype skull in multiple views
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Clade: Archosauria
Clade: Pseudosuchia
Clade: Crocodylomorpha
Clade: Crocodyliformes
Suborder: †Thalattosuchia
Family: †Machimosauridae
Subfamily: †Machimosaurinae
Tribe: †Machimosaurini
Genus: †Lemmysuchus
Johnson, Young et al., 2017
Species:
†L. obtusidens
Binomial name
†Lemmysuchus obtusidens
Andrews, 1909
Synonyms

Lemmysuchus is a genus of machimosaurid thalattosuchian from the Middle Jurassic Callovian of England and France. Like many other teleosauroids from Europe, it has had a convoluted taxonomic history.

History

[edit]
Skull and other elements of the holotype specimen

"Steneosaurus" obtusidens was first described from the Callovian-aged Oxford Clay Formation of Cambridgeshire, southeastern England on the basis of a partial skeleton (NHMUK R.3168).[1] Characters cited as diagnostic for "S." obtusidens included: short rostrum (preorbital length 52 percent of total skull length); teeth blunt and rounded at the tips; armor adorned with elongate pit ornamentation.

The validity of "Steneosaurus" obtusidens was disputed in a 1987 paper reviewing the type specimens of nominal teleosauroid species from the Oxford Clay. Characters used by Charles William Andrews to distinguish "S." obtusidens from other species were dismissed as variable within specimens of Steneosaurus edwardsi, and "S." obtusidens was sunk as a junior synonym of Steneosaurus durobrivensis (=S. edwardsi).[2] Some authors considered this taxon a probable junior synonym of Machimosaurus hughii based on a subsequently discovered specimen found in Callovian-age exposures in Calvados, Lower Normandy, France, though they stressed that a taxonomic review of blunt-snouted teleosaurids was needed.[3][4] This synonymy was accepted in a 2009 paper regarding thalattosuchian morphometrics without comment.[5]

In 2013, a new specimen of Machimosaurus was described from Late Jurassic (Kimmeridgian deposits in southern Germany (later named Machimosaurus buffetauti), and it became clear that variation within blunt-toothed teleosauroids was taxonomically significant enough for "Steneosaurus" obtusidens to be recognized as generically distinct from Machimosaurus.[6] Other cladistic and comparative studies agreed with this assessment, recovering "S." obtusidens in a clade with Machimosaurus and Steneosaurus edwardsi.[7][8][9][10]

In 2017, the species was moved to its own genus, Lemmysuchus, referring to Ian Fraser Kilmister, better known as "Lemmy", of the band Motörhead,[11] and the Greek word for crocodile, soukhos.[12]

References

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  1. ^ Andrews, C.W. (1909). "On some new Steneosaurs from the Oxford Clay of Peterborough". Annals and Magazine of Natural History. 3 (15): 299–308. doi:10.1080/00222930908692579.
  2. ^ Adams-Tresman, S. M. (1987). "The Callovian (Middle Jurassic) teleosaurid marine crocodiles from central England". Palaeontology. 30 (1): 195–206.
  3. ^ Hua, Vignaud; Pennetier; Pennetier (1994). "Un squelette de Steneosaurus obtusidens Andrews, 1909 dans le Callovien de Villers-sur-mer(Calvados, France)et le problème de la definition des Teleosauridae à dents obtuses". Comptes Rendus de l'Académie des Sciences, Série II. 318: 1557–1562.
  4. ^ Hua, S., 1999, Le Crocodilien Machimosaurus mosae (Thalattosuchia, Teleosauridae) du Kimmeridgien du Boulonnais (Pas de Calais, France): Palaeontographica Abt. A., v. 252, Lfg. 4-6, p. 141-170.
  5. ^ Pierce, S. E.; Angielczyk, K. D.; Rayfield, E. J. (2009). "Morphospace occupation in thalattosuchian crocodylomorphs: skull shape variation, species delineation and temporal patterns" (PDF). Palaeontology. 52 (5): 1057–1097. doi:10.1111/j.1475-4983.2009.00904.x.
  6. ^ Martin, J. E.; Vincent, P. (2013). "New remains of Machimosaurus hugii von Meyer, 1837 (Crocodilia, Thalattosuchia) from the Kimmeridgian of Germany". Fossil Record. 16 (2): 179–196. doi:10.1002/mmng.201300009.
  7. ^ Mueller-Töwe, IJ (2005). "Phylogenetic relationships of the Thalattosuchia". Zitteliana. 45: 211–213.
  8. ^ Young, M. T.; Brusatte, S. L.; De Andrade, M. B.; Desojo, J. B.; Beatty, B. L.; Steel, L.; Fernández, M. S.; Sakamoto, M.; Ruiz-Omeñaca, J. I.; Schoch, R. R. (2012). "Butler, Richard J, ed. "The Cranial Osteology and Feeding Ecology of the Metriorhynchid Crocodylomorph Genera Dakosaurus and Plesiosuchus from the Late Jurassic of Europe". PLOS ONE. 7 (9): e44985. doi:10.1371/journal.pone.0044985. PMC 3445579. PMID 23028723.
  9. ^ Young, M. T.; Hua, S.; Steel, L.; Foffa, D.; Brusatte, S. L.; Thüring, S.; Mateus, O.; Ignacio-Ruiz Omeñaca, J.; Lepage, Y.; Havilk, P.; Andrade, M. B. (2014). "Revision of the Late Jurassic teleosaurid genus Machimosaurus (Crocodylomorpha, Thalattosuchia)". Royal Society Open Science. 1 (140222): 1–42. Bibcode:2014RSOS....140222Y. doi:10.1098/rsos.140222. PMC 4448888. PMID 26064545.
  10. ^ Johnson, MM; Young, MT; Steel, L; Foffa, D; Smith, AS; Hua, S; Havlik, P; Howlett, EA; Dyke, G (2018). "Re-description of 'Steneosaurus' obustidens Andrews, 1909, an unusual macrophagous teleosaurid crocodylomorph from the Middle Jurassic of England". Zoological Journal of the Linnean Society. 182 (2): 385–418. doi:10.1093/zoolinnean/zlx035.
  11. ^ "Scaly snuggle-toothed beast? That'll be Lemmy" > Daily Telegraph Issue no 50,455 dated Wednesday 9 August 2017
  12. ^ Johnson, Michela M.; Young, Mark T.; Steel, Lorna; Foffa, Davide; Smith, Adam S.; Hua, StÉphane; Havlik, Philipe; Howlett, Eliza A.; Dyke, Gareth (2017). "Re-description of 'Steneosaurus' obtusidens Andrews, 1909, an unusual macrophagous teleosaurid crocodylomorph from the Middle Jurassic of England". Zoological Journal of the Linnean Society. 182 (2): 385–418. doi:10.1093/zoolinnean/zlx035.
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