Kritosaurus
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Kritosaurus Temporal range: Late Cretaceous, 74.5–66 Ma |
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| K. navajovius skull, AMNH | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Reptilia |
| Clade: | Dinosauria |
| Order: | †Ornithischia |
| Suborder: | †Ornithopoda |
| Family: | †Hadrosauridae |
| Subfamily: | †Saurolophinae |
| Tribe: | †Kritosaurini |
| Genus: |
†Kritosaurus Brown, 1910 |
| Type species | |
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†Kritosaurus navajovius Brown, 1910 |
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| Species | |
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†K. navajovius Brown, 1910 |
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| Synonyms | |
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Anasazisaurus? Hunt & Lucas, 1993 |
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†K. navajovius Brown, 1910
†K. horneri? Hunt & Lucas, 1993
Anasazisaurus? Hunt & Lucas, 1993
Kritosaurus is an incompletely known genus of hadrosaurid (duck-billed) dinosaur. It lived about 74.5-66 million years ago, in the Late Cretaceous of North America. The name means "separated lizard" (referring to the arrangement of the cheek bones in an incomplete type skull), but is often mistranslated as "noble lizard" in reference to the presumed "Roman nose" (in the original specimen, the nasal region was fragmented and disarticulated, and was originally restored flat).
The type specimen of Kritosaurus navajovius is only represented by a partial skull and lower jaws, and associated postcranial remains. The greater portion of the muzzle and upper beak are missing. The length of the skull is estimated at 87 centimeters (34 in) from the tip of the upper beak to the base of the quadrate that articulates with the lower jaw at the back of the skull. Potential diagnostic characteristics of Kritosaurus include a predentary (lower beak) without tooth-like crenulations, a sharp downward bend to the lower jaws near the beak, and a heavy, somewhat rectangular maxilla (upper tooth-bearing bone).
Based on the skull originally referred to Anasazisaurus, the form of the complete crest is that of a tab or flange of bone, from the nasals, that rises between and above the eyes and folds back under itself. This unique crest allows it to be distinguished from similar hadrosaurs, like Gryposaurus. The top of the crest is roughened, and the maximum preserved length of the skull is ~90 centimeters (~35 in).
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