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Nuove specie di dinosauri corazzati rinvenute in Cina

Nuova ricostruzione del dinosauro corazzato Asia

Questo è il primo dinosauro corazzato trovato in tutta l’Asia e ci aiuta a capire quando e dove questi animali sono apparsi per la prima volta. Credito: © Yu Chen

Dalla Cina è stata descritta una nuova specie di dinosauro corazzato. Questi sono i primi resti fossili di questo gruppo trovati in Asia, aiutando a capire come questi strani dinosauri si sono evoluti e diffusi in tutto il mondo.

I dinosauri corazzati sono alcuni dei dinosauri più famosi, inclusi animali famosi come Stegosauro e Anchilosauro.

Infatti, uno dei primi dinosauri nominati fu un dinosauro corazzato, una specie di anchilosauro scoperta nel West Sussex noto come Hylaeosaurus.

Questa nuova scoperta proviene da un animale che visse molto prima di queste specie conosciute e aiuta gli scienziati a capire quando e dove sono apparsi per la prima volta i dinosauri corazzati prima di colonizzare rapidamente il resto del mondo.

Il professor Paul Barrett, un ricercatore sui dinosauri del museo che si concentra sui dinosauri erbivori, insieme ai suoi colleghi cinesi ha contribuito a descrivere la nuova specie.

“La documentazione fossile consiste in uno scheletro abbastanza completo, comprese parti del cranio, vertebre, parti degli arti e una grande quantità di armature. È il primo esempio di dinosauro corazzato meglio conservato di tutta l’Asia.

“L’armatura ci dice immediatamente che è un membro dello stesso gruppo di dinosauri degli stegosauri e degli anchilosauri, ma l’età del dinosauro ci dice che è un membro precoce, leggermente al di fuori di uno di questi gruppi e quindi vicino all’antenato comune di entrambi”.

Il documento descrive e nomina Yuxisaurus kopchicki è stato pubblicato sulla rivista eVita.

Nuovo scheletro asiatico di dinosauro corazzato

Oltre alle ossa dell’animale sono stati rinvenuti anche numerosi pezzi di armatura. Credito fotografico: © Xi Yao

L’origine dei dinosauri corazzati

Durante[{” attribute=””>Jurassic and into the New Armored Dinosaur Asia Excavation

This part of China is rich in dinosaur fossils, but it has largely been dominated by sauropods and their relatives. Credit: ©Shundong Bi

In the past, thyreophoran dinosaurs have largely been associated with the rocks dating to the Late Jurassic and Cretaceous periods (163-66 million years ago) of North America and Europe. This has revealed an incredible diversity of species, but it has long been known that their origins must go much further back.

This historic paucity of finds from the southern continents has led to some suggesting that the group must have evolved in the north. But recent finds are muddying this opinion, with both the earliest known ankylosaur and stegosaur unearthed in the same rock formation in Morocco and dating to around 165 million years ago.

“There are early armored dinosaurs starting to turn up more in the south,” explains Paul. “There are two animals from about 200 million years ago from Venezuela and South Africa, that don’t have armor, but might be the earliest members of the group, showing what they looked like before they evolved armor.

“If these animals were in the group then it is likely the armored dinosaurs originated in the southern continents, but this idea is controversial. If they aren’t included in the group, then the origins are anchored in the northern hemisphere. At the moment, we’ve no way to choose between these alternatives.”

New Armored Dinosaur Asia

The new find helps to fill out what we know about this part of the world during the Early Jurassic some 192-174 million years ago. Credit: ©Yu Chen

A cosmopolitan dinosaur

This new discovery is not the earliest-known member of this group, but a contemporary of a number of other species from around the world, such as species in Germany and the UK. What this find does do is help to fill in the picture of what this region in China looked like at this moment in time and how these animals were evolving.

This particular formation in China has revealed other dinosaur fossils, but so far it is dominated by the large, long-necked sauropods and their early relatives. This new find adds to the diversity of the other herbivores that must have also been present in the ecosystem at the time.

The fact that Yuxisaurus dates to the Early Jurassic is also of interest. The animal is different from the other early armored dinosaurs as it has a stockier build and a distinctive arrangement of armored plates that would have covered its back. This suggests that these early animals were experimenting with their body shapes and ecology earlier than scientists previously thought.

“The armored dinosaurs appeared at the start of the Jurassic and within a few million years were already evolving into quite a few different types,” explains Paul. “In addition to that they achieved a worldwide distribution very early in their history.

“A bunch of really early members of stegosaurs and ankylosaurs from slightly later in time have been found spread around the world, so they must have been able to move across and between continents.

“Until recently, we assumed that all armored dinosaur evolution happened in the north, but new finds are showing that this was not true.”

Reference: “A new early branching armored dinosaur from the Lower Jurassic of southwestern China” by Xi Yao, Paul M Barrett, Lei Yang, Xing Xu and Shundong Bi, 15 March 2022, eLife.
DOI: 10.7554/eLife.75248