''Mosaiceratops'' is a genus of

ceratopsia Ceratopsia or Ceratopia ( or ; Greek: "horned faces") is a group of herbivorous, beaked dinosaurs that thrived in what are now North America, Europe, and Asia, during the Cretaceous Period, although ancestral forms lived earlier, in the Jurass ...

n, described by Zheng, Jin & Xu in 2015 and found in the

Xiaguan Formation The Xiaguan Formation is a Turonian to Campanian geologic formation in Henan Province of China.

of Neixiang County. ''Mosaiceratops'' lived in the upper

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...

in what is now the Henan Province of

China China, officially the People's Republic of China (PRC), is a country in East Asia. It is the world's List of countries and dependencies by population, most populous country, with a Population of China, population exceeding 1.4 billion, slig ...

. 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.Zheng, W., Jin, X., & Xu, X. (2015)
A psittacosaurid-like basal neoceratopsian from the Upper Cretaceous of central China and its implications for basal ceratopsian evolution
''Scientific reports'', 5. article number 14190: 1-9; doi:10.1038/srep14190

Discovery

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. In 2015, the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specim ...

''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 Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through ...

''mosaicus'' and Greek ''keras'', "horn" and ''ops'', "face". The specific name honours the Japanese paleontologist Yoichi Azuma, the discoverer of ''

Archaeoceratops ''Archaeoceratops'', meaning "ancient horned face", is a genus of basal neoceratopsian dinosaur from the Early Cretaceous (Aptian stage) of north central China. It appears to have been bipedal and quite small, reaching in length and in body ...

''. ''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 Xiaguan Formation dating from the Turonian- Campanian. It is an incomplete and disarticulated skeleton with skull. It includes

pelvis The pelvis (plural pelves or pelvises) is the lower part of the trunk, between the abdomen and the thighs (sometimes also called pelvic region), together with its embedded skeleton (sometimes also called bony pelvis, or pelvic skeleton). The ...

bones and leg bones (

femur The femur (; ), or thigh bone, is the proximal bone of the hindlimb in tetrapod vertebrates. The head of the femur articulates with the acetabulum in the pelvic bone forming the hip joint, while the distal part of the femur articulates ...

tibia The tibia (; ), also known as the shinbone or shankbone, is the larger, stronger, and anterior (frontal) of the two bones in the leg below the knee in vertebrates (the other being the fibula, behind and to the outside of the tibia); it conn ...

fibula The fibula or calf bone is a leg bone on the lateral side of the tibia, to which it is connected above and below. It is the smaller of the two bones and, in proportion to its length, the most slender of all the long bones. Its upper extremity ...

, ischium, ilium, some phalanges and metatarsals,

calcaneum In humans and many other primates, the calcaneus (; from the Latin ''calcaneus'' or ''calcaneum'', meaning heel) or heel bone is a bone of the tarsus of the foot which constitutes the heel. In some other animals, it is the point of the hock. S ...

and astragalus), twenty-four vertebrae (three cervicals, three dorsals and eighteen caudals), a dorsal rib, a humerus, a

radius In classical geometry, a radius (plural, : radii) of a circle or sphere is any of the line segments from its Centre (geometry), center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', ...

and the anterior part of an articulated

skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, th ...

with a disarticulated postorbital bone and squamosal. The articulated skull preserves the rostral bone,

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has ...

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. T ...

jugal bone The jugal is a skull bone found in most reptiles, amphibians and birds. In mammals, the jugal is often called the malar or zygomatic. It is connected to the quadratojugal and maxilla, as well as other bones, which may vary by species. Ana ...

, quadratojugal, dentary, surangular, angular bone, the anterior section of the

prefrontal bone The prefrontal bone is a bone separating the lacrimal and frontal bones in many tetrapod skulls. It first evolved in the sarcopterygian clade Rhipidistia, which includes lungfish and the Tetrapodomorpha. The prefrontal is found in most mo ...

, and the anterior part of the

nasal bone The nasal bones are two small oblong bones, varying in size and form in different individuals; they are placed side by side at the middle and upper part of the face and by their junction, form the bridge of the upper one third of the nose. Ea ...

. The fossils are part of the collection of the Zhejiang Museum of Natural History.

Description

''Mosaiceratops'' was a relatively small dinosaur, reaching in length and in body mass. It can be distinguished by four

autapomorphic In phylogenetics, an autapomorphy is a distinctive feature, known as a derived trait, that is unique to a given taxon. That is, it is found only in one taxon, but not found in any others or outgroup taxa, not even those most closely related to ...

, 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. Mosaiceratops Scale

Furthermore a unique combination is present of traits that in themselves are not unique. The premaxilla is edentulous, meaning it lacks teeth. The premaxilla is somewhat wider than the maxilla in lateral view (the presence of that trait is plesiomorphic, being shared with '' Psittacosaurus''). The nasal bone has a front lower branch extending under the bony nostril. The jugal bone is formed as an inverted T. The postorbital is T-shaped with slender descending and rear branches. The inner branch of the squamosal bone points obliquely to the front and inside. The front branch of the squamosal is not forked. The basal tubers of the occiput are separated by a wide middle notch. More in general, the skull overall is more similar to advanced taxa like '' Aquilops'' or '' Liaoceratops''.

Classification

Zheng ''et al.'' (2015), the describers of ''Mosaiceratops'', recovered the genus as the most basal known neoceratopsian, closer to ''

Triceratops ''Triceratops'' ( ; ) is a genus of herbivorous chasmosaurine ceratopsid dinosaur that first appeared during the late Maastrichtian stage of the Late Cretaceous period, about 68 million years ago in what is now North America. It is one ...

'' than ''Psittacosaurus''. Before the description of ''Mosaiceratops'', the most basal known neoceratopsian was either ''Aquilops'' or ''Liaoceratops'', depending on the analysis. However, they noted that this position was not strongly supported in their phylogenetic analysis, acknowledging the possibility that ''Mosaiceratops'' instead represents the sister taxon to ''Psittacosaurus'' (in which case the name Psittacosauridae would be reinstated). In their description of the postcrania of '' Yinlong'', Han ''et al.'' (2018) noted that the external naris of ''Mosaiceratops'' was not as positioned as high as in ''Psittacosaurus'', and recovered ''Mosaiceratops'' as more derived than ''Liaoceratops'' and ''Aquilops''.Fenglu Han; Catherine A. Forster; Xing Xu; James M. Clark (2017). "Postcranial anatomy of Yinlong downsi (Dinosauria: Ceratopsia) from the Upper Jurassic Shishugou Formation of China and the phylogeny of basal ornithischians". Journal of Systematic Palaeontology. in press. doi:10.1080/14772019.2017.1369185.

References

{{Taxonbar, from=Q21011930 Ceratopsians Late Cretaceous dinosaurs of Asia Fossil taxa described in 2015 Paleontology in Henan Ornithischian genera

Discovery

Description

Classification

See also

References