Sunday, February 25, 2024

[Paleontology • 2024] Datai yingliangis • A New Armored Dinosaur (Ankylosauria: Ankylosauridae) with double cheek horns from the early Late Cretaceous of southeastern China


Datai yingliangis
Xing, Niu, Mallon & Miyashita, 2024

Reconstruction by Kaitlin T. Lindblad

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 yinliangis gen. et sp. nov. Despite the immature ontogenetic status of the type materials, D. yingliangis can be diagnosed with autapomorphic traits in the cranial caputegulae (such as double horns on the 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 forms or forms a sister lineage to Pinacosaurus. Based on these insights, Datai 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.

Keywords: Ankylosauria, Ankylosaurinae, Zhoutian Formation, Guanzhou Group

The type specimens of Datai yingliangis gen. et ap. nov. (individual lying on top: YLSNHM 01003; individual on bottom: YLSNHM 01002, holotype) prepared and reconstructed in situ. The head, cervical, and thoracic regions of the specimens were discovered and extracted from a single block.

Dinosauria Owen, 1842
Ornithischia Seeley, 1887
Thyreophora Nopcsa, 1915
Ankylosauria Osborn, 1923
Ankylosauridae Brown, 1906

Datai gen. nov.

Etymology: 'Datai,' a composite of the last character (syllable) each from tongda (to understand/to be sensible) and antai (stable) in Chinese Pinyin.

Datai yingliangis sp. nov.

Diagnosis: An ankylosaurine with dual jugal/quadratojugal horns. This taxon is also distinguished from all other ankylosaurines with a unique combination of the following characters: protruded premaxilla such that prenarial portion is longer than infranarial portion (also present in Zhongyuansaurus luoyangensis), distinct 'postfrontal' caputegulum (also in Pinacosaurus mephistocephalus and Talarurus plicatospineus), well-developed supraorbitals forming no lacrimal incisure or postorbital peak (potentially controlled ontogenetically), parasagittaly projecting squamosal horn (also in Scolosaurus cutleri/Oohkotokia horneri), nuchal horn (also in Ankylosaurus magniventris, Euoplocephalus tutus, Nodocephaosaurus kirtlandensis, Zuul crurivastator), and polygonal, monotypic gular osteoderms covering the interman-dibular region and the entire throat (polymorphic gular osteoderms occur in Jinyunpelta sinensis).

Type locality and horizon: Zhoutian Formation, Ganzhou Group (Turonian–early Coniacian; Upper Cretaceous; 96–90 Ma).

Etymology: 'yingliangis', in recognition of the Yingliang Group. The Yingliang Stone Natural History Museum is operated as a public museum by the philanthropic program of the founder (Liang Liu) of the Yingliang Group, and the type specimens are curated in this museum in Shuitou, Fujiang, China.

Lida Xing, Kecheng Niu, Jordan Mallon and Tetsuto Miyashita. 2024. A New Armored Dinosaur with double cheek horns from the early Late Cretaceous of southeastern China. Vertebrate Anatomy Morphology Palaeontology. 11. DOI: 10.18435/vamp29396