Paleontologists have revealed a new species of armored dinosaur with a "tail club" that served as a weapon.
The dinosaur, named Huaxiazhoulong shouwen, would likely have measured around 20 feet in length and stood around 5 feet tall at the hip, Ziheng Zhu, a researcher with the Center for Vertebrate Evolutionary Biology at Yunnan University, China, told Newsweek. Zhu is the lead author of a study describing the previously unknown dinosaur published in the journal Historical Biology.
The newly identified species was described based on a fossil specimen originally recovered in 1986 from Longxi village within the Tangbian geological formation of Jiangxi Province in southern China. The deposits it in which it was found date to the Campanian age of the Late Cretaceous epoch, meaning between roughly 84 and 72 million years ago.
According to the study authors, the new species was a member of a family of heavily armored, herbivorous dinosaurs called Ankylosauridae that lived between the Late Jurassic (around 165 million to 145 million years ago) to the Late Cretaceous (around 101 million to 66 million years ago).
These dinosaurs are best known for their extensive body armor, including bony plates (known as osteoderms) embedded in the skin and, in some species, a distinctive club-like tail used for defense. Ankylosaurids were quadrupedal, with low, broad bodies and strong limbs adapted for supporting their massive weight. These dinosaurs primarily inhabited regions of North America, Asia, and Europe, thriving in a diverse array of environments.
In the case of Huaxiazhoulong, the fossil specimen on which the new species was described is "relatively complete," Zhu said. It consists of a partial skeleton including various vertebrae, ribs, limb bones, tail bones and osteoderms, among other remains. The specimen, housed in the collection of the Jiangxi Provincial Museum, appears to represent the largest ankylosaur ever found in China.
The "most distinctive" feature of Huaxiazhoulong is its ischium -- which forms the lower and back region of the hip bone -- according to Zhu. This ischium has a distinct characteristic that has not been seen in other ankylosaurids -- one that allows more muscles to be attached. This likely provided the dinosaur with increased power in its lower body.
Another interesting aspect of the fossil is its scapula, or shoulder blade, that features a "special" bulge.
"Although some Ankylosaurs also have this structure, it is not as developed as Huaxiazhoulong, indicating that [the dinosaur] had well-developed shoulders, which could better support its body or dig caves," Zhu said.
"In addition to the strong shoulders... the tail of Huaxiazhoulong is also interesting. Like other ankylosaurs, the tail had a tail club that could be used to attack enemies. If you look carefully, you will find that the club is asymmetrical, suggesting that the Huaxiazhoulong may have its own preferred direction just like humans: left-handed or right-handed."
While estimating the living weight of a dinosaur is generally difficult, comparisons with its relatives indicate that Huaxiazhoulong may have weighed around 3 tons, according to Zhu.
The species name is derived from several components. The first word in the name contains the term "Huaxia" -- a reference to "China" in Chinese Mandarin. The first word also contains the term "zhou" meaning "armor" and "long" meaning "dragon". Meanwhile, the second word in the name -- "shouwen" -- means "painted in the shape of a beast" in Chinese.
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Zhu, Z., Wu, J., You, Y., Jia, Y., Chen, C., Yao, X., Zheng, W., & Xu, X. (2024). A new ankylosaurid dinosaur from the Upper Cretaceous of Jiangxi Province, southern China. Historical Biology, 1-17. https://doi.org/10.1080/08912963.2024.2417208