Pararhabdodon
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| Pararhabdodon isonensis Casanovas-Cladellas, Santafé-Llopis, and Isidoro-Llorens, 1993 |
Pararhabdodon (meaning "similar to Rhabdodon" ["bar-tooth"]) was a genus of derived hadrosauroid or basal hadrosaurid dinosaur, from the Maastrichtian-age Upper Cretaceous Tremp Formation of Spain. It is based on assorted postcranial remains, mostly vertebrae, and is notable for the reassignments it has undergone in regards to classification.
[edit] History
In 1987, Casanovas et al. described remains of an ornithopod from northeastern Spain, including a cervical vertebra, some partial dorsals, a humerus, and a fragmentary scapula, as Rhabdodon sp.[1] New remains from this site (Tremp Formation, near Isona, Lleida, Spain) brought about a reconsideration of the material, and Casanovas-Cladellas et al. named Pararhabdodon isonense in 1993 from a middle caudal vertebra (IPS-SRA-15), referring additional material to their new genus.[2] At the time, it was considered to be a rhabdodont-like basal iguanodont, hence the name.[2]
Additional material from the type locality was collected in 1994, and the species name was corrected to isonensis in 1997 by Casanovas-Cladellas et al. and Laurent et al.[3][4] A dentary (IPS SRA 27) from a second quarry in the Tremp Formation was also referred to the genus, now considered to be a basal lambeosaurine hadrosaurid.[3] Laurent et al referred additional remains (jaw material, vertebrae, and limb bones of multiple individuals of different ages) from the uppermost Cretaceous of Aude, France, to the genus,[4] but this was not discussed in the most recent review.[5] (Oddly, the second edition of The Dinosauria omitted this genus altogether)
Head (2001) disputed the assignment to the Lambeosaurinae, considering it more likely to be basal to the two hadrosaurid subfamilies.[6] This is the same conclusion that Prieto-Marquez et al. (2006) came to, finding it to be the sister group to Hadrosaurinae+Lambeosaurinae ( = Hadrosauridae in their analysis, although the definition of Hadrosauridae varies).[5] Prieto-Marquez assigned IPS SRA 27 to its own genus, Koutalisaurus, a more derived hadrosaurid.[5]
[edit] Paleobiology
Pararhabdodon most likely was a bipedal-quadrupedal herbivore, in the neighborhood of 6 m (19.7 ft) long, fully grown.[5] The dorsal and sacral neural spines were elongate, so the animal would have had a tall back, like other hadrosaurids. Because the material is sparse, more specific conclusions cannot be reached. Spanish material includes: a maxilla; four cervical, four dorsal, and a caudal vertebra; a sacrum; the end of an ischium; and a humerus.[5]
[edit] References
- ^ Casanovas, M.L, Santafé, J.S., Sanz, J.L., and Buscalioni, A.D. (1987). [Archosaurs (Crocodilia, Dinosauria) from the Upper Cretaceous of the Tremp Basin (Lleida, Spain)]. Estudios Geológicos. Volumen extraordinario Galve-Tremp:95-110. [Spanish]
- ^ a b Casanovas-Cladellas, M.L., Santafé-Llopis, J.V., and Isidoro-Llorens, A. (1993). [Pararhabdodon isonense n. gen. n. sp. (Dinosauria). Morphology, radio-tomographic study, and biomechanic considerations]. Paleontologia i Evolució 26-27:121-131. [Spanish]
- ^ a b Casanovas, M.L, Pereda-Suberbiola, X., Santafé, J.V., and Weishampel, D.B. (1999). First lambeosaurine hadrosaurid from Europe: palaeobiogeographical implications. Geological Magazine 136(2):205-211.
- ^ a b Laurent, Y., LeLoeuff, J., and Buffetaut, E. (1997). [The Hadrosauridae (Dinosauria, Ornithopoda) from the Upper Maastrichtian of the eastern Corbières (Aude, France)]. Revue de Paléobiologie 16:411-423. [French]
- ^ a b c d e Prieto-Marquez, A., Gaete, R., Rivas, G., Galobart, Á., and Boada, M. (2006). Hadrosauroid dinosaurs from the Late Cretaceous of Spain: Pararhabdodon isonensis revisited and Koutalisaurus kohlerorum, gen. et sp. nov. Journal of Vertebrate Paleontology 26(4): 929-943.
- ^ Head, J.J. (2001). A reanalysis of the phylogenetic position of Eolambia caroljonesa (Dinosauria, Iguanodontia). Journal of Vertebrate Paleontology 21(2):392-396.
