''Datai'' is an

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

genus of

ankylosaurid Ankylosauridae () is a family of armored dinosaurs within Ankylosauria, and is the sister group to Nodosauridae. The oldest known ankylosaurids date to around 122 million years ago and went extinct 66 million years ago during the Cretaceous–Pal ...

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...

from the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the more recent of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''cre ...

Zhoutian Formation The Zhoutian Formation () is a geological formation in Jiangxi, China. It has been dated to the late Cretaceous period, at about 96–90 Ma. Abundant egg fossils are known from the formation, in addition to dinosaurs such as ''Datai'' and ''Gandit ...

Jiangxi Province ; Gan: ) , translit_lang1_type2 = , translit_lang1_info2 = , translit_lang1_type3 = , translit_lang1_info3 = , image_map = Jiangxi in China (+all claims hatched).svg , mapsize = 275px , map_caption = Location ...

China China, officially the People's Republic of China (PRC), is a country in East Asia. With population of China, a population exceeding 1.4 billion, it is the list of countries by population (United Nations), second-most populous country after ...

. The genus contains a single species, ''D. yingliangis'', which is known from the

articulated An articulated vehicle is a vehicle which has a permanent or semi-permanent coupling in its construction. This coupling works as a large pivot joint, allowing it to bend and turn more sharply. There are many kinds, from heavy equipment to buse ...

skulls and partial skeletons of two individuals.

Discovery and naming

The ''Datai'' fossil material was discovered in 2016, in sediments of the

in Mazhou, Huichang County, Jiangxi Province, China. The fossils were then obtained by the Yingliang Stone Natural History Museum two years later, where they are currently stored. The two known specimens—representing different ages of immaturity—were found articulated and in association. The

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

specimen, YLSNHM 01002, consists of a skull, four

dorsal vertebrae In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae of intermediate size between the ce ...

ribs The rib cage or thoracic cage is an endoskeletal enclosure in the thorax of most vertebrates that comprises the ribs, vertebral column and sternum, which protect the vital organs of the thoracic cavity, such as the heart, lungs and great vessels ...

, four

distal Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position provi ...

caudal vertebrae Caudal vertebrae are the vertebrae of the tail in many vertebrates. In birds, the last few caudal vertebrae fuse into the pygostyle, and in apes, including humans, the caudal vertebrae are fused into the coccyx. In many reptiles, some of the caud ...

surrounded by

ossified Ossification (also called osteogenesis or bone mineralization) in bone remodeling is the process of laying down new bone material by cells named osteoblasts. It is synonymous with bone tissue formation. There are two processes resulting in t ...

tendon A tendon or sinew is a tough band of fibrous connective tissue, dense fibrous connective tissue that connects skeletal muscle, muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tensi ...

s (likely indicative of the presence of a tail club), incomplete

pectoral girdle The shoulder girdle or pectoral girdle is the set of bones in the appendicular skeleton which connects to the arm on each side. In humans, it consists of the clavicle and scapula; in those species with three bones in the shoulder, it consists o ...

s, the left arm (including the

humeral The humerus (; : humeri) is a long bone in the arm that runs from the shoulder to the elbow. It connects the scapula and the two bones of the lower arm, the radius and ulna, and consists of three sections. The humeral upper extremity consists of ...

head and distal

radius In classical geometry, a radius (: radii or radiuses) 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 radius of a regular polygon is th ...

and

ulna The ulna or ulnar bone (: ulnae or ulnas) is a long bone in the forearm stretching from the elbow to the wrist. It is on the same side of the forearm as the little finger, running parallel to the Radius (bone), radius, the forearm's other long ...

), a fragmentary left ilium, a distal right

femur The femur (; : femurs or femora ), or thigh bone is the only long bone, bone in the thigh — the region of the lower limb between the hip and the knee. In many quadrupeds, four-legged animals the femur is the upper bone of the hindleg. The Femo ...

, several

osteoderms Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of Extant taxon, extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, Temnospondyli, ...

. The

paratype In zoology and botany, a paratype is a specimen of an organism that helps define what the scientific name of a species and other taxon actually represents, but it is not the holotype (and in botany is also neither an isotype (biology), isotype ...

specimen, YLSNHM 01003, also includes a skull, in addition to all of the

cervical vertebrae In tetrapods, cervical vertebrae (: vertebra) are the vertebrae of the neck, immediately below the skull. Truncal vertebrae (divided into thoracic and lumbar vertebrae in mammals) lie caudal (toward the tail) of cervical vertebrae. In saurop ...

, five dorsal vertebrae, incomplete pectoral girdles, the left elbow region (distal humerus and

proximal Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

radius and ulna), and osteoderms. In 2024, Xing ''et al.'' described ''Datai yingliangis'' as a new genus and species of

ankylosaurine Ankylosaurinae is a subfamily of ankylosaurid dinosaurs, existing from the Early Cretaceous about 105 million years ago until the end of the Late Cretaceous, about 66 mya. Many genera are included in the clade, such as ''Ankylosaurus'', ''Pinacos ...

dinosaur based on these fossil remains. The generic name, ''Datai'', is a composite of the last characters of the Chinese words 'tongda' (to understand/to be sensible) and 'antai' (stable). The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

, ''yingliangis'', is in recognition of the Yingliang Group.

Classification

Xing Lida pointed out that in the past, ankylosaurian

phylogenies A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In o ...

had little stability with many

clade In biology, a clade (), also known as a Monophyly, monophyletic group or natural group, is a group of organisms that is composed of a common ancestor and all of its descendants. Clades are the fundamental unit of cladistics, a modern approach t ...

s tending to collapse into polytomies. In the study he used the traits of ''Datai'' to improve the resolution. For their phylogenetic analysis, Xing ''et al.'' (2024) tested two character matrices. The first was based on the findings of Zheng ''et al.'' (2018) with fourteen poorly preserved taxa being deleted or "pruned" by Xing, and the second was based on the findings of Raven ''et al.'' (2023) with 34-taxon deletion. The first tree recovers ''Datai'' as a basal

, while the second recovers it as a sister taxon to the two ''

Pinacosaurus ''Pinacosaurus'' (meaning "Plank lizard") is a genus of ankylosaurid thyreophoran dinosaur that lived in Asia during the Late Cretaceous (Campanian, roughly 75 to 71 million years ago), mainly in Mongolia and China. The first remains of the genu ...

'' species. Both trees are reproduced below excluding the outgroups for improved readability:

References

{{taxonbar, from1=Q124616010, from2=Q124616017 Ankylosaurinae Dinosaur genera Turonian dinosaurs Coniacian dinosaurs Fossil taxa described in 2024 Dinosaurs of China