Mosaiceratops is a genus of ceratopsian, described by Zheng, Jin & Xu in 2015 and found in the Xiaguan Formation of Neixiang County. Mosaiceratops lived in the upper Cretaceous in what is now the Henan Province of China.
Although phylogenetic analyses have found Mosaiceratops to be the most basal neoceratopsian, the authors noted that several features in the premaxilla and nasal bones are shared with Psittacosaurus, indicating that neoceratopsians evolved premaxillary teeth twice and that Psittacosaurus is not as primitive as previously thought.[1]
On the westbank of the river Tuanhe in Neixiang in Henan the skeleton was discovered of a small ceratopian. The fossil was prepared by Sheng Yiming and Yu Chaohe.[1]
In 2015, the type species Mosaiceratops azumai was named and described by Zheng Wenjie, Jin Xingsheng and Xu Xing. The generic name Mosaiceratops means "mosaic horned face", which refers to the mosaic of features normally found on basal neoceratopsians, psittacosaurids and other basal ceratopsians, especially the lack of premaxillary teeth. It is a combination of Latin mosaicus and Greek keras, "horn" and ops, "face". The specific name honours the Japanese paleontologist Yoichi Azuma, the discoverer of Archaeoceratops.[1] Mosaiceratops was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals.[2]
The holotype, ZMNH M8856, was found in a layer of the Xiaguan Formation dating from the Turonian-Campanian. It is an incomplete and disarticulated skeleton with skull. It includes pelvis bones and leg bones (femur, tibia, fibula, ischium, ilium, some phalanges and metatarsals, calcaneum and astragalus), twenty-four vertebrae (three cervicals, three dorsals and eighteen caudals), a dorsal rib, a humerus, a radius and the anterior part of an articulated skull with a disarticulated postorbital bone and squamosal. The articulated skull preserves the rostral bone, premaxilla, maxilla, jugal bone, quadratojugal, dentary, surangular, angular bone, the anterior section of the prefrontal bone, and the anterior part of the nasal bone. The fossils are part of the collection of the Zhejiang Museum of Natural History.[1]
Mosaiceratops was a relatively small dinosaur, reaching 1 m (3.3 ft) in length and 10 kg (22 lb) in body mass.[3] It can be distinguished by four autapomorphic, unique derived traits: the presence of an evident groove between the premaxilla and the maxilla in lateral view; the elongation of the anterior part of the jugal having a parallel upper edge and lower edge; the main body of the jugal below the eye sockets bears two small bumps; in the ilium the extremity of the upper edge of the rear blade is pointed obliquely to above and behind.[1]