Mosaiceratops
A small ceratopsian dinosaur with a mosaic of ancestral and derived traits.
Mosaiceratops is a ceratopsian dinosaur whose fossils were uncovered in China’s Henan Province, specifically from the Upper Cretaceous Majiacun Formation. In 2015, Zheng Wenjie, Jin Xingsheng, and Xu Xing named and described the type species *Mosaiceratops azumai*. While phylogenetic studies place it as the most basal neoceratopsian, the original authors pointed out that certain traits in its premaxilla and nasal bones resemble those of *Psittacosaurus*. This suggests that neoceratopsians developed premaxillary teeth on two separate occasions, and that *Psittacosaurus* may not be as primitive as scientists once believed.
The skeleton of this small ceratopsian was found on the west bank of the Tuanhe River in Neixiang, Henan. Fossil preparation was carried out by Sheng Yiming and Yu Chaohe. The genus name *Mosaiceratops* combines Latin *mosaicus* with Greek *keras* (“horn”) and *ops* (“face”), referring to the mix of features seen in basal neoceratopsians, psittacosaurids, and other early ceratopsians—especially the presence of premaxillary teeth, a trait it shares with psittacosaurids while being a neoceratopsian. The species name honors Japanese paleontologist Yoichi Azuma, who discovered *Archaeoceratops*. *Mosaiceratops* was among eighteen dinosaur taxa described in 2015 in open-access or free-to-read journals.
The holotype specimen, ZMNH M8856, comes from a layer of the Majiacun Formation dating to the Turonian–Santonian interval. It consists of an incomplete, disarticulated skeleton with a skull. Preserved elements include pelvic bones, leg bones (femur, tibia, fibula, ischium, ilium, some phalanges and metatarsals, calcaneum, astragalus), twenty-four vertebrae (three cervicals, three dorsals, eighteen caudals), a dorsal rib, a humerus, a radius, and the front part of a disarticulated skull along with a disarticulated postorbital and squamosal. The skull remains disarticulated but retains the rostral bone, premaxilla, maxilla, jugal, quadratojugal, dentary, surangular, angular, the front section of the prefrontal, and the front part of the nasal. These fossils belong to the Zhejiang Museum of Natural History.
*Mosaiceratops* was relatively small, reaching about 1 meter in length and weighing around 10 kilograms.
Quick Facts
- Genus
- Mosaiceratops
- Species
- azumai
Facts from the source article.
Lore & Background
The skeleton of Mosaiceratops was discovered on the west bank of the river Tuanhe in Neixiang, Henan, China. The fossil was prepared by Sheng Yiming and Yu Chaohe. In 2015, the type species Mosaiceratops azumai was named and described by Zheng Wenjie, Jin Xingsheng, and Xu Xing. The generic name means 'mosaic horned face,' referring to the mosaic of features normally found on basal neoceratopsians, psittacosaurids, and other basal ceratopsians, especially the presence of premaxillary teeth—a trait that links it to psittacosaurids while being a neoceratopsian. The specific name honors Japanese paleontologist Yoichi Azuma, discoverer of Archaeoceratops. Mosaiceratops was one of eighteen dinosaur taxa from 2015 to be described in open access or free-to-read journals.
The holotype, ZMNH M8856, was found in a layer of the Majiacun Formation dating from the Turonian-Santonian. It is a disarticulated skeleton, with the skull preserved as separate, disarticulated elements rather than an articulated unit.
Reader's Guide
Mosaiceratops holds significance in ceratopsian evolution as a genus that challenges previous assumptions about the primitive nature of Psittacosaurus. Described in 2015, it was recovered as the basalmost known neoceratopsian in the phylogenetic analysis of its describers, though they noted this position was not strongly supported. The mosaic of features—including premaxillary traits shared with Psittacosaurus—suggests that neoceratopsians evolved premaxillary teeth twice, implying that Psittacosaurus is not as primitive as once thought. Later work by Han et al. (2018) noted that the external naris of Mosaiceratops was not as high as in Psittacosaurus and recovered it as more derived than Liaoceratops and Aquilops. The uncertainty in its exact placement underscores the complexity of early ceratopsian relationships. Its small size and disarticulated skeleton provide valuable anatomical data, and its description in an open-access journal reflects a trend toward broader accessibility in paleontological research.
Did You Know?
- Mosaiceratops was named for the mosaic of features found on basal neoceratopsians, psittacosaurids, and other basal ceratopsians.
- The specific name azumai honors Japanese paleontologist Yoichi Azuma, discoverer of Archaeoceratops.
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