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Lambeosaurus in new JVP
Evans, D.C. & R.R. Reisz, 2007. Anatomy and relationships of Lambeosaurus
magnicristatus, a crested hadrosaurid dinosaur (Ornithischia) from the
Dinosaur Park Formation, Alberta. Journal of Vertebrate Paleontology 27
Abstract: The first detailed description of the lambeosaurine Lambeosaurus
magnicristatus (Ornithischia: Hadrosauridae) confirms that it is a distinct
taxon characterized by its comparatively enormous cranial crest, formed
predominantly by the caudodorsal process of the premaxilla, and an acute
crest-snout angle. The holotype of L. magnicristatus occurs
stratigraphically higher than all other Dinosaur Park Formation
lambeosaurines at the Dinosaur Provincial Park locality. The only referred
specimen was collected over 170 kilometers southeast of the type locality.
Correlation of its host stratum with the well-known Dinosaur Park section
reveals that L. magnicristatus has no biostratigraphic overlap with L.
lambei and suggests that it replaces L. lambei on a regional scale in
southern Alberta at the end of ?Dinosaur Park time.? Species-level
phylogenetic analysis of Lambeosaurinae corroborates the monophyly of
Lambeosaurus. The genus is characterized by five apomorphies, including a
procumbent crest, complete enclosure of the ophthalmic canal of the
laterosphenoid, the presence of a flange on the caudodorsal process of the
premaxilla that overlaps the nasal in the rostral region of the crest,
caudal extension of the premaxilla such that it forms the caudal margin of
the crest, and a unique joint between the rostral nasal and the caudodorsal
process of the premaxilla. Lambeosaurine phylogeny indicates that the
development of a hypertrophied cranial crest evolved independently at least
three times within the clade, suggesting that the crest enlargement is a
recurring evolutionary trend within Lambeosaurinae.
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