''Jinyunpelta'' ("Jinyun shield") is a genus of herbivorous

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 ...

thyreophoran Thyreophora ("shield bearers", often known simply as "armored dinosaurs") is a group of armored ornithischian dinosaurs that lived from the Early Jurassic until the end of the Cretaceous. Thyreophorans are characterized by the presence of bod ...

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

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

Liangtoutang Formation of

Jinyun County Jinyun County is a county of south-central Zhejiang province, China. It is under the administration of the Lishui Lishui (; Lishuinese: ''li⁶ syu³'' ) is a prefecture-level city in the southwest of Zhejiang province, People's Republic o ...

Zhejiang ) , translit_lang1_type2 = , translit_lang1_info2 = ( Hangzhounese) ( Ningbonese) (Wenzhounese) , image_skyline = 玉甑峰全貌 - panoramio.jpg , image_caption = View of the Yandang Mountains , image_map = Zhejiang i ...

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 ...

; it has one species, the

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

''J. sinensis''. This species is the basalmost ankylosaur known to have had a proper tail club.

Discovery and naming

In June 2008, farmer Li Meiyun on a construction site at Huzhen in

discovered the remains of an ankylosaur. Between 2008 and 2014 excavations took place by a joint team of the Zhejiang Museum of Natural History, the Jinyun Museum and the Fukui Prefectural Dinosaur Museum. In 2013, five ankylosaurian skeletons were uncovered. A new species was to be based on two of these, while preparation of the other finds continued. In 2018, the type species ''Jinyunpelta sinensis'' was named and described by Zheng Wenjie, Jin Xingsheng, Yoichi Azuma, Wang Qiongying, Kazunori Miyata and Xu Xing. The generic name combines Jinyun with a Greek ''peltè'', "small shield", a usual suffix in the names of ankylosaurians. 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 ...

refers to the provenance from China. 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 ...

, ZMNH M8960, was found in a layer of the Liangtoutang Formation dating from the

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

Cenomanian The Cenomanian is, in the International Commission on Stratigraphy's (ICS) geological timescale, the oldest or earliest age (geology), age of the Late Cretaceous epoch (geology), Epoch or the lowest stage (stratigraphy), stage of the Upper Cretace ...

, about one hundred million years old. It consists of a partial skeleton, with a complete skull, but lacking most of the hindlimbs, apart from the right humerus and the left thighbone. 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 ...

is ZMNH M8963, a skeleton lacking the skull but including the left lower leg and a complete tail club. It was found at two to three metres distance from the holotype.

Description

The describing authors indicated a number of distinguishing traits. Some of these were

autapomorphies 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 characters. Behind the nostril two additional openings are present, in ankylosaurids named the "C1" and the "C2", which in the case of ''Jinyunpelta'' are on a level with the centre of the nostril. On the front upper edge of the

maxilla In vertebrates, the maxilla (: maxillae ) 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. The two maxil ...

a triangular depression is present. The postorbital bone does not contribute to the rear edge of the eye socket. In the lower jaw, the front part of the prearticular bone is positioned beneath the rear part of the splenial bone. Obliquely above and to the inside of the inner condyle of the thighbone a distinct tendon scar is present. Additionally, ''Jinyunpelta'' shows a unique combination of traits that in themselves are not unique. The combined upper side of the nasal bones is pierced by two paired oval openings. The antorbital fossa, with ankylosaurs the remnant of the

antorbital fenestra An antorbital fenestra (plural: fenestrae) is an opening in the skull that is in front of the eye sockets. This skull character is largely associated with Archosauriformes, archosauriforms, first appearing during the Triassic Period. Among Extant ...

, extends over the contact point of the maxilla, lacrimal bone and jugal bone. The prefrontal bone extends to below, touching the maxilla. At least some dorsal vertebrae have an elongated centrum, 30% longer than wide. The tail club is hexagonal in top view, with the widest point located near the rear edge. ''Jinyunpelta'' is known to have exhibited biphasal jaw movement, an adaptation that had previously been thought only to have evolved in ankylosaurids during the

Campanian The Campanian is the fifth of six ages of the Late Cretaceous epoch on the geologic timescale of the International Commission on Stratigraphy (ICS). In chronostratigraphy, it is the fifth of six stages in the Upper Cretaceous Series. Campa ...

Phylogeny

In 2018, ''Jinyunpelta'' was, within the

Ankylosauridae 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 ...

, placed in the

Ankylosaurinae 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'', ''Pinac ...

. This would imply that it was the oldest known ankylosaurine. A

cladistic Cladistics ( ; from Ancient Greek 'branch') is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is ...

analysis showed that it was also the basalmost known ankylosaurine, placed below '' Crichtonpelta'' in the evolutionary tree. It would then furthermore be the oldest and basalmost ankylosaurid that is with certainty known to possess a tail club; previously this had been ''

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 ...

'' dating from the

. The size of the tail club shows that this trait must have been developed early-on in the evolution of ankylosaurids. Additionally, ''Jinyunpelta'' was the most southern known ankylosaurid from Asia. In

phylogenetic In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...

analyses by Xing ''et al''. (2024), ''Jinyunpelta'' is recovered as a member of Ankylosaurinae or as a basal ankylosaurid. Below are two simplified

cladogram A cladogram (from Greek language, Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an Phylogenetic tree, evolutionary tree because it does not s ...

s from that study: Topology A: Zheng ''et al''. (2018) dataset + ''

Datai ''Datai'' is an extinct genus of ankylosaurid dinosaur from the Late Cretaceous Zhoutian Formation of Jiangxi Province, China. The genus contains a single species, ''D. yingliangis'', which is known from the articulated skulls and partial skele ...

'' (14-taxon deletion) Topology B: Raven ''et al''. (2023) dataset + ''

'' (34-taxon deletion)

References

{{Taxonbar, from=Q50244145 Ankylosaurinae Dinosaur genera Cenomanian dinosaurs Fossil taxa described in 2018 Dinosaurs of China

Discovery and naming

Description

Phylogeny

See also

References