Turanoceratops

Turanoceratops ("Turan horned face") is a genus of herbivorous ceratopsian dinosaur from the late Cretaceous Bissekty Formation of Uzbekistan. The fossils dated from the mid-late Turonian stage, roughly 90 million years ago. The skull bore a pair of long brow horns like those seen in the Ceratopsidae, although Turanoceratops appears to have been transitional between earlier ceratopsians and ceratopsids, and not a ceratopsid itself.

Discovery and naming
From the 1920s onwards, Soviet scientists discovered fragmentary fossils near Dzharakuduk in the district Navoi Viloyat, leading them to the conclusion that some ceratopid must have been present. In 1988, paleontologist Lev Aleksandrovich Nesov based on these published the name Turanoceratops tardabilis,[1] but did not provide a description so that for the time being it remained a nomen nudum. In 1989, Nesov, L.F. Kaznysjkina and Gennady Olegovich Cherepanov validly named the type species Turanoceratops tardabilis. The generic name is a combination of Turan, an old Persian name for Turkestan, the general region of the finds, and ~ceratops, "horned face", a usual suffix in ceratopian names. The specific name means "retarding" in Latin, referring to the protracted research.[2]

The holotype, CCMGE No. 251/12457, consists of a damaged left maxilla, the tooth-bearing upper jaw bone. Other fossils have been referred but some of these later were proven to have belonged to other types of dinosaur. A braincase e.g. (specimen CCGME 628/12457) was shown to be of a sauropod, while presumed frill material actually represented ankylosaur armour plates. Authentic material includes postorbitals with brow horn cores, teeth, a predentary and limb elements.

In 2004, Peter Dodson considered it a nomen dubium,[3] but in 2009 Hans-Dieter Sues concluded that it was a valid taxon.

Description
Turanoceratops was a relatively small animal. In 2010, Gregory S. Paul estimated its length at two metres, its weight at 175 kilogrammes.[5]

Sues in 2009 determined some typically basal traits, indicating a more low position in the evolutionary tree, and some more derived traits, showing a more high position. Basal traits are the variably developed secondary ridges on the tooth crowns and the possession of just two or three teeth per tooth position. Derived traits, relative to the more basal Zuniceratops, are the increase of the number of teeth to two or three and the possession of two roots per teeth. More general derived traits are the exclusion of the frontal bone from the upper rim of the eye socket and the presence of incipient cavities in the skull roof.