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Larry Dunn wrote:
<<Could someone please give me a summary of the reason that
Gasparinisaura is assigned to Euiguanodontia? What distinguishes it
from basal iguanodontians such as Tenontosaurus and Muttaburrasaurus?>>
Quoted from Coria and Salgado's diagnoses for Euiguanodontia, they "[share]
the following synapomorphies: 26) jugal-postorbital articulation facing
laterally, 27) lateral primary ridge in maxillary teeth, 28) wide brevis
shelf, 29) metatarsal one reduced or absent. . ."
Unfortunately for C&S, character 27 appears to be present in Tenontosaurus
(pers obs) and 29 seems to have arrisen independantly at least three times
within Ornithopoda (Gaspirinisaura, Dryosauridae, and Hadrosauroidea).
Don't fret however, if you're a fan of Euiguanodontia (as I know you all are),
there appear to be several more characters present in euiguanodontian taxa
that are absent in Tenontosaurus that Coria and Salgado didn't notice... They
ALSO seem to be present in a certain North American ornithopod that has been
regarded as a run of the mill hypsilophodont.. More on that this fall.
For Muttaburrasaurus try:
Bartholomai, A and Molnar, R E. 1981. Muttaburrasaurus, a new iguanodontid
(Ornithischia: Ornithopoda) dinosaur from the Lower Cretaceous of Queensland.
Memoirs of the Queensland Museum 20(2):319-349.
Molnar, R E. 1996. Observations on the Australian ornithopod dinosaur,
Muttaburrasaurus. In: Novas, F A, Molnar, R E (eds) Proceedings of the
Gondwanan Dinosaur Symposium. Memoirs of the Queensland Museum 39(3):639-652.
And for Tenontosaurus, you should check out:
Forster, C A. 1990. The postcranial skeleton of the ornithopod dinosaur
Tenontosaurus tilletti. Journal of Vertebrate Paleontology 10(3):273-294.
Ostrom, J H. 1970. Stratigraphy and paleontology of the Cloverly Formation
(Lower Cretaceous) of the Bighorn Basin area, Wyoming and Montana. Bulletin
of the Peabody Museum of Natural History 35:1-234.
Winkler, D A, Murry, P A, and Jacobs, L L. 1997. A neew species of
Tenontosaurus (Dinosauria: Ornithopoda) from the Early Cretaceous of Texas.
Journal of Vertebrate Paleontology 17(2):330-348.
<<Also, have any South American iguanodontians popped up since G.?>>
There are a couple of hadrosaurs which have been known since the seventies,
but nothing really new has popped up since 1996 with any ornithischian taxa
(well at least not officially). Look for some new stuff concerning these guys
some time in the next one to two years.