Datai

MEANING: Sensible and stable

PERIOD: Late Cretaceous

CONTINENT: Asia

Like all ankylosaurs, Datai was a quadrupedal herbivore, covered in an armor of bony osteoderms. It is notable for the double horns on its cheeks. The preserved specimens were two subadults lying gregariously together, suggesting the possibility that ankylosuars may have sometimes lived in small groups, at least as juveniles.

Abstract from paper: Ankylosaurines are the iconic armoured dinosaurs that characterize terrestrial vertebrate faunas in the Late Cretaceous of Asia and Laramidia (western North America). The earliest members of this clade are known from the early Late Cretaceous (Cenomanian–Santonian) times of Asia, but little consensus has emerged as to how they are related to the anatomically derived and chronologically younger forms. In southeastern China, the Cretaceous red sand beds crop out across basins from Zhejiang to Guandong provinces. However, the horizons corresponding to the early Late Cretaceous stages remain poorly sampled. Here, we report the first definitive vertebrate skeleton — let alone that of an armoured dinosaur — from the Coniacian/Turonian Ganzhou Formation, Datai yingliangis gen. et sp. nov. Despite the immature ontogenetic status of the type materials, D. yingliangis gen. et sp. nov. can be diagnosed with autapomorphic traits in the cranial caputegulae (such as double horns on the jugal/quadratojugal) and extensive gular osteoderms. Morphologically, it is intermediate between the chronologically older ankylosaurids from Asia (e.g., Crichtonpelta and Jinyunpelta) and derived post-Cenomanian ankylosaurines (e.g., Pinacosaurus). Phylogenetic analyses broadly corroborate this assessment. The new taxon either falls in the grade of Asian ankylosaurines proximal to the lineages of derived taxa or forms a sister lineage to Pinacosaurus. Based on these insights, Datai gen. nov. makes a significant addition to the early Late Cretaceous vertebrate fauna from southeastern China and highlights the future potential in this region for improved understanding of the origin and early evolution of ankylosaurines.

Datai is from the Late Cretaceous. The Cretaceous is the third and final geological period of the Mesozoic Era, with the Late Cretaceous making up roughly the second half of it, lasting from about 100 to 66 million years ago. It was a time of significant evolutionary change, with dinosaurs reaching their greatest diversity before the mass extinction at the end of the Cretaceous.

The Cretaceous was a period with a relatively warm climate, though the Late Cretaceous experienced a global cooling trend, caused by falling levels of carbon dioxide in the atmosphere. The continents were nearing their present positions, but high sea levels flooded low-lying regions, turning Europe into an archipelago, and forming the Western Interior Seaway in North America. These seas were home to a variety of marine reptiles, including mosasaurs and plesiosaurs, while pterosaurs and birds shared the skies.

On land, dinosaurs continued to thrive and diversify during the Late Cretaceous, producing many of the most well-known goups, including tyrannosaurs, hadrosaurs, and pachycephalosaurs. Established Cretaceous dinosaur clades like the ceratopsians, ankylosaurs, and dromaeosaurs continued to flourish. Sauropod species consisted almost exclusively of titanosaurs, which seemed to be confined to the Southern Hemisphere for much of the Late Cretaceous. Flowering plants and grasses diversified and spread, becoming the dominant flora similar to what we see today.

The Cretaceous (along with the Mesozoic) ended with the Cretaceous-Paleogene (K-Pg) extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out. This event, likely triggered by an asteroid impact, is marked by the abrupt K-Pg boundary, a distinct geologic layer separating the Mesozoic and Cenozoic Eras. In its aftermath, mammals and avian dinosaurs rapidly diversified, becoming the dominant land animals of the Cenozoic Era.

Datai is an ankylosaurid. Ankylosaurids are a family of armored dinosaurs within Ankylosauria, best known for the large bony clubs at the ends of their tails, distinguishing them from their nodosaurid relatives. Like all ankylosaurs, they were herbivorous, quadrupedal, and covered in bony osteoderms for defense. Ankylosaurids typically had broader, more triangular skulls, shorter limbs, and a more compact body compared to nodosaurids.

They first appeared in the Early Cretaceous and persisted until the end of the Mesozoic. Fossils of ankylosaurids are most commonly found in North America and Asia. Ankylosauridae and nodosauridae make up the larger group ankylosauria, which, along with the stegosaurs, form the group Thyreophora, known for their various combinations of armor and spikes.