Dongyangopelta
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''Dongyangopelta'' (meaning "Dongyang shield") is an
monospecific In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...
genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
of
nodosaurid Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the s ...
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 ...
that lived in
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 ...
during the Early to Late Cretaceous period (Albian to Cenomanian stages, 105-96 Ma) in what is now the Chaochuan Formation. The type and only known species, ''Dongyangopelta yangyanensis'', is known from a partial postcranial skeleton preserving osteoderms and ossified tendons. It was named in 2013 by Rongjun Chen, Wenjie Zheng, Yoichi Azuma, Masateru Shibata, Tianling Lou, Qiang Jin and Xinsheng Jin. ''Dongyangopelta'' represents one of the only nodosaurids known from Asia, along with ''
Taohelong ''Taohelong'' is a genus of nodosaurid dinosaur known from Lower Cretaceous rocks in north-central China. ''Taohelong'' is based on Gansu Dinosaur Museum (GSDM) 00021, fossils including a tail vertebra, ribs, a left ilium (the main bone of th ...
'' and ''
Sauroplites ''Sauroplites'' (meaning "saurian hoplite") is a genus of herbivorous ankylosaurian dinosaur from the Early Cretaceous of China. Discovery and naming In 1930, the Swedish paleontologist Anders Birger Bohlin during the Swedish-Chinese expeditions ...
''.


Discovery and naming

In October 2009, a partial
skeleton A skeleton is the structural frame that supports the body of most animals. There are several types of skeletons, including the exoskeleton, which is a rigid outer shell that holds up an organism's shape; the endoskeleton, a rigid internal fra ...
of an
ankylosaur Ankylosauria is a group of herbivorous dinosaurs of the clade Ornithischia. It includes the great majority of dinosaurs with armor in the form of bony osteoderms, similar to turtles. Ankylosaurs were bulky quadrupeds, with short, powerful l ...
was discovered by Zhiwei Yang in rocks of the Chaochuan Formation, in a hillside beside the Yangyan Village southeast of the Donyang City, Zhejiang Province, China. Subsequently, a joint excavation to retrieve the skeleton was conducted from September to October 2010 by a number of institutes such as the Zhejiang Museum of Natural History, Dongyang Museum,
Fukui Prefectural Dinosaur Museum The , located in Katsuyama, Fukui, Japan, is one of the leading dinosaur museums in Asia that is renowned for its exhibits of fossil specimens of dinosaurs and paleontological research. It is sited in the Nagaoyama Park ( Katsuyama Dinosaur Fore ...
, Institute of Geology, Chinese Academy of Sciences and Hydrogeological Engineering Geological Brigade of Zhejiang Province. Notable individuals involved in the excavation and preparation of the specimen include Chaohe Yu and Guangming Luo. The Chaochuan Formation consists of purplish
sandstone Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
s with interbedded
igneous rock Igneous rock ( ), or magmatic rock, is one of the three main rock types, the others being sedimentary and metamorphic. Igneous rocks are formed through the cooling and solidification of magma or lava. The magma can be derived from partial ...
, while the layer bearing the partial skeleton consists of brown sandstone that lie in between gray igneous rocks. The layer dates to 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 ...
to
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 ...
stages of the
Early Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican d ...
to
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 ...
, 105 to 96 Ma. The specimen was described and named by Rongjun Chen, Wenjie Zheng, Yoichi Azuma, Masateru Shibata, Tianliang Lou, Qiang Jin and Xingsheng Jin in
2013 2013 was the first year since 1987 to contain four unique digits (a span of 26 years). 2013 was designated as: *International Year of Water Cooperation *International Year of Quinoa Events January * January 5 – 2013 Craig, Alask ...
. The generic name, ''Dongyangopelta'', combines the Chinese word "''Dongyang''", in reference to the Donyang City, and the Greek word "''pelta''" (shield). The specific name, ''yangyanensis'', is in reference to the Yangyan Village. The holotype specimen, DYM F0136, consists of sacrodorsal vertebrae,
sacral vertebrae The sacrum (: sacra or sacrums), in human anatomy, is a triangular bone at the base of the spine that forms by the fusing of the sacral vertebrae (S1S5) between ages 18 and 30. The sacrum situates at the upper, back part of the pelvic cavity, ...
, dorsal ribs,
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 ...
, pedal
phalanges The phalanges (: phalanx ) are digit (anatomy), digital bones in the hands and foot, feet of most vertebrates. In primates, the Thumb, thumbs and Hallux, big toes have two phalanges while the other Digit (anatomy), digits have three phalanges. ...
, partial Ilium fused to two sacral ribs,
ossified tendons A tendon or sinew is a tough band of dense fibrous connective tissue that connects muscle to bone. It sends the mechanical forces of muscle contraction to the skeletal system, while withstanding tension. Tendons, like ligaments, are made of ...
and numerous
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, ...
.


Description

The preserved sacrodorsal vertebrae of ''Dongyangopelta'' have large neural arches, small neural canals and an elongated centrum. The prezygapophyses and postzygapophyses of the sacrodorsal vertebrae are fused together. The sacral vertebrae have a broad centra, with no groove or ridge. Of the few vertebrae preserved, some have ribs that are fused to the transverse processes. The right ilium preserves hourglass shaped sacral ribs. The greater part of the illium projects above the articulation with the femur. The femur measures 46 cm (18.1 in) in length. It is straight and robust, with a curving posteriorly femoral shaft. The femoral head is distinct and is separated from the great trochanter by a change in slope. The distal end of the femur is robust, with a large medial condyle and a small lateral condyle. The non-ungual phalanges are broad and short. The ungual phalanx is rectangular and similarly broad to the non-ungual phalanges. Rod-like ossified tendons were preserved in the matrix and vary from compressed to circular in cross section. The pelvic shield is made up of numerous fused osteoderms that form a rosette pattern, with the central, larger osteoderms not being completely ringed by smaller osteoderms. Numerous other osteoderms are known from different parts of the body, including thin triangular plates that range in length from 10 to 35 cm (3.9 to 13.8 in), domed osteoderms and cone-shaped osteoderms. Small, circular ossicles may have been arranged in a mosaic patterning around these types of osteoderms.


Classification

Chen and colleagues (2013) assigned ''Dongyangopelta'' to the clade
Nodosauridae Nodosauridae is a family of ankylosaurian dinosaurs known from the Late Jurassic to the Late Cretaceous periods in what is now Asia, Europe, North America, and possibly South America. While traditionally regarded as a monophyletic clade as the ...
, based on the femoral head being well separated from the great trochanter. A
phylogenetic analysis 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 data ...
found it to be
sister taxon In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree. Definition The expression is most easily illustrated by a cladogram: Taxon A and ...
of the Asian ''
Zhejiangosaurus ''Zhejiangosaurus'' (meaning "Zhejiang lizard") is an extinct genus of ankylosaurian dinosaur from the Upper Cretaceous (Cenomanian stage) of Zhejiang, eastern China. It was first named by a group of Chinese authors Lü Junchang, Jin Xingsheng, S ...
''. Later, a phylogenetic analysis performed by Arbour and Currie (2015) recovered it within a polytomy with ''
Sauroplites ''Sauroplites'' (meaning "saurian hoplite") is a genus of herbivorous ankylosaurian dinosaur from the Early Cretaceous of China. Discovery and naming In 1930, the Swedish paleontologist Anders Birger Bohlin during the Swedish-Chinese expeditions ...
'' and ''
Taohelong ''Taohelong'' is a genus of nodosaurid dinosaur known from Lower Cretaceous rocks in north-central China. ''Taohelong'' is based on Gansu Dinosaur Museum (GSDM) 00021, fossils including a tail vertebra, ribs, a left ilium (the main bone of th ...
'' at the base of Nodosauridae. A similar result was replicated by Rivera-Sylva and colleagues (2018), with the only difference being the inclusion of ''
Mymoorapelta ''Mymoorapelta'' (Meaning "Shield from the Mygatt-Moore Quarry" after a combination of the names of the discoverers of the Mygatt-Moore Quarry that fossils were originally collected from, and the Greek word πέλτα, meaning "shield") is a Nod ...
'' and the exclusion of ''Taohelong'' within the
polytomy An internal node of a phylogenetic tree is described as a polytomy or multifurcation if (i) it is in a rooted tree and is linked to three or more child subtrees or (ii) it is in an unrooted tree and is attached to four or more branches. A tree ...
. A 2018 study performed by Zheng and colleagues considered it to be sister taxon to ''Mymoorapelta''. A phylogenetic analysis conducted by Rivera-Sylva et al. (2018) and modified by Madzia et al. (2021) is reproduced below.


See also

*
Timeline of ankylosaur research This timeline of ankylosaur research is a chronological listing of events in the History of paleontology, history of paleontology focused on the ankylosaurs, quadrupedal herbivorous dinosaurs who were protected by a covering bony plates and spik ...


References

{{Taxonbar, from=Q17126083 Nodosauridae Dinosaur genera Albian dinosaurs Cenomanian dinosaurs Fossil taxa described in 2013 Dinosaurs of China