From Wikipedia, the free encyclopedia
Jump to: navigation, search
Temporal range: Middle Jurassic
Poekilopleuron bucklandi.JPG
Cast of the holotype gastralia
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Superorder: Dinosauria
Order: Saurischia
Suborder: Theropoda
Superfamily: Allosauroidea
Family: Sinraptoridae
Genus: Poekilopleuron
Eudes-Deslongchamps, 1838
  • P. bucklandii Eudes-Deslongchamps, 1838 (type)


Megalosauroid dorsal vertebrae referred by Owen to Poekilopleuron




Megalosauroid neural arch and spine referred by Owen to Poekilopleuron

Five other species would be named in the genus. In 1869 Edward Drinker Cope renamed Laelaps gallicus into Poekilopleuron gallicum. In 1870 Joseph Leidy created a Poicilopleuron valens based on a fossil probably belonging to Allosaurus.[4] In 1876 Richard Owen named a Poikilopleuron pusillus, in 1879 renamed by Cope to Poekilopleuron minor; in 1887 Harry Govier Seeley made it a separate genus: Aristosuchus.[5] In 1883 W.A. Kiprijanow created a Poekilopleuron schmidti, of which the specific name honours Friedrich Schmidt, based on some indeterminate ribs and a sauropod metatarsal.[6] This chimaera is a nomen dubium. A much later named species is Poekilopleuron valesdunensis created by Ronan Allain in 2002.[7] In 2005 it was renamed Dubreuillosaurus.[8]

The most distinctive feature of Poekilopleuron were its forelimbs. Their length, about 60 cm, was a sign of this theropod's more original build. Unlike later Theropoda, whose forelimbs tended toward reduction in length in proportion to the animals' size, Poekilopleuron's were long and, by implication, potent. The length mostly resided in the elongated but powerfully muscled humerus. The antebrachia (forearms) were markedly short and robust, a characteristic shared with Poekilopleuron's slightly later and considerably larger American cousin Torvosaurus. A unique feature is a lack of the olecranon process on the ulna.[9]

The fossil of Poekilopleuron showed a rare complete set of gastralia: fourteen pair of belly ribs supported the body of the animal.

Because the original fossil was destroyed and no other remains of Poekilopleuron have since been found, and also because of its name change, there is much controversy surrounding its classification that cannot be resolved. Traditionally it has been assigned to the Megalosauridae, but some recent analyses showed a position in the Sinraptoridae; others had as result it was a member of Megalosauroidea, in a basal position or in the Eustreptospondylinae. Benson et al. (2010) found it and Lourinhanosaurus to belong to Sinraptoridae.[10]

The material of Poekilopleuron bucklandii includes two tail vertebrae with the chevron of one vertebra ankylosed to the centrum of the next within the development of an exostosis. Two phalanges also preserve pathologies. One probable pedal phalanx shows three low, irregular exostosis-like projections. A second probable manual phalanx exhibits a "low rounded projection resembling a callus." Ralph Molnar considered the occurrence of three pathologies in one individual to be "noteworthy". Sadly the specimens cannot be examined further to determine the etiology of the pathologies because of their destruction during the British bombing raid in 1944.[11]


  1. ^ Allain R (2001). "Redescription de Streptospondylus altdorfensis, le dinosaure théropode de Cuvier, du Jurassique de Normandie [Redescription of Streptospondylus altdorfensis, Cuvier's theropod dinosaur from the Jurassic of Normandy]" (PDF). Geodiversitas 23 (3): 349–367. 
  2. ^ Eudes-Deslongchamps A (1837). "Mémoire sur le Poekilopleuron bucklandi, grande saurien fossile, intermédiare entre les crocodiles et les lézards, découvert dans les carrières de la Maladrerie, près Caen, au mois de juillet 1835". Mémoires de la Société Linnéenne Normandie 6: 1–114. 
  3. ^ Hulke J.W. (1879). "Note on Poekilopleuron bucklandi of Eudes Deslongchamps (père), identifying it with Megalosaurus bucklandi". Quarterly Journal of the Geological Society 35 (1-4): 233–238. doi:10.1144/GSL.JGS.1879.035.01-04.10. 
  4. ^ Leidy J (1870). "Remarks on Poicilopleuron valens, Clidastes intermedius, Leiodon proriger, Baptemys wyomingensis, and Emys stevensonianus". Proceedings of the Academy of Natural Sciences 22 (1): 3–4. JSTOR 4624064. 
  5. ^ Seeley H.G. (1887). "On Aristosuchus pusillus Owen, being further notes on the fossils described by Sir R. Owen as Poikilopleuron pusillus Owen". Quarterly Journal of the Geological Society of London 43: 221–228. doi:10.1144/GSL.JGS.1887.043.01-04.22. 
  6. ^ Kiprijanow W.A. (1883). "Studien über die Fossilen Reptilien Russlands. IV. Theil. Ordnung Crocodilia Oppel. Indeterminierte Fossile Reptilien". Mémoires de l'Académie Impériale des Sciences de Saint-Pétersbourg. VIIe série 31 (7): 1–29. 
  7. ^ Allain R (2002). "Discovery of megalosaur (Dinosauria, Theropoda) in the Middle Bathonian of Normandy (France) and its implications for the phylogeny of basal Tetanurae". Journal of Vertebrate Paleontology 22 (3): 548–563. doi:10.1671/0272-4634(2002)022[0548:DOMDTI]2.0.CO;2. 
  8. ^ Allain R (2005). "The postcranial anatomy of the megalosaur Dubreuillosaurus valesdunensis (Dinosauria: Theropoda) from the Middle Jurassic of Normandy, France". Journal of Vertebrate Paleontology 25 (4): 850–858. doi:10.1671/0272-4634(2005)025[0850:TPAOTM]2.0.CO;2. 
  9. ^ Allain R., Chure D. J. (2002). "Poekilopleuron bucklandii, the theropod dinosaur from the Middle Jurassic (Bathonian) of Normandy". Palaeontology 45 (6): 1107–1121. doi:10.1111/1475-4983.00277. 