Poekilopleuron
From Greek poikilos (varied, diverse) and pleuron (rib); meaning "varied ribs".
Poekilopleuron is a genus of megalosaurid theropod dinosaur, which lived during the middle Bathonian of the Jurassic, about 168 to 166 million years ago. The genus has been used under many different spelling variants, although only one, Poekilopleuron, is valid. The type species is P. bucklandii, named after William Buckland, and many junior synonyms of it have also been erected. Little material is currently known, as the holotype was destroyed in World War II, although many casts of the material still exist.
Under dispute
Poekilopleuron bucklandii is a fragmentary taxon, its holotype destroyed in World War II, with an unstable position. Carrano and colleagues (2012) recover it tentatively as an afrovenatorine megalosaurid but note that a single step moves it to Piatnitzkysauridae or Allosauria; Benson (2010) recovers it as an allosauroid; and Cau (2024) treats it as a megalosauroid and the senior synonym of Dubreuillosaurus.
Diagnosis
- Highly varied gastral (belly-rib) apparatus: unpaired chevron-shaped ribs together with paired ribs bearing small accessory stylet ossicles — the diverse rib arrangement for which the genus is named
- Marked disproportion between a small, weakly built forelimb and a powerfully built hindlimb
- Robust, compact humerus with a well-developed deltoid crest extending about halfway down the shaft
- Strongly compressed, sharply curved (hooked) manual ungual, differing markedly in form from the pedal unguals
Species
Poekilopleuron bucklandii Eudes-Deslongchamps, 1837
Type species
Named for William Buckland, the English geologist and paleontologist, deliberately matching the species epithet of Megalosaurus bucklandii in case the two genera were later synonymized.
- Holotype
- Not catalogued , Université de Caen Normandie (destroyed)
- Material
- A partial skeleton: forelimb (humerus, radius, ulna, manus) and hind limb (femur, tibia, fibula, pes) bones, about 21 caudal vertebrae, numerous dorsal and abdominal ribs, and a possible pubis; no skull.
- Horizon
- Calcaire de Caen Formation, Bathonian, Middle Jurassic , 168.2–165.3 million years ago
- Locality
- La Maladrerie, Calvados, France
References
-
Eudes-Deslongchamps, J. A. (1836). Plusieurs parties d'un mémoire sur un très-grand animal fossile découvert, l'an dernier, dans les carrières de la Maladrerie à un quart de lieu de Caen. Analyse des Travaux de la Société Pendant l'Année Académique 1835–1836, Séance Publique de la Société Linnéenne de Normandie Tenue à Vire le 24 Mai 1836 14-25.
In French.
eudes-deslongchamps1836a - Eudes-Deslongchamps, J. 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 [Memoir on the Poekilopleuron bucklandi, a Great Fossil Saurian, Intermediate between Crocodiles and Lizards, Discovered in the Maladrerie Quarries, near Caen, in July 1835]. 1-114. A. Hardel. eudes-deslongchamps1837a
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Cau, A. (2024). A Unified Framework for Predatory Dinosaur Macroevolution. Bollettino della Società Paleontologica Italiana 63(1): 1-19. doi:10.4435/BSPI.2024.08
Treated Poekilopleuron as a megalosauroid and the senior synonym of Dubreuillosaurus.
cau2024a -
Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). The phylogeny of Tetanurae (Dinosauria: Theropoda). Journal of Systematic Palaeontology 10(2): 211-300. Informa UK Limited. doi:10.1080/14772019.2011.630927
Tetanurae phylogeny tentatively recovered Poekilopleuron as an afrovenatorine megalosaurid.
carrano2012a -
Benson, R. B. J. (2010). A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society 158(4): 882-935. Oxford University Press (OUP). doi:10.1111/j.1096-3642.2009.00569.x
Recovered it as an allosauroid rather than an afrovenatorine megalosaurid
benson2010c