The newly-discovered dinosaur species, Lishulong wangi, lies in the heart of the early sauropodomorph-sauropod transition, according to a paper published in the journal PeerJ.
Photograph (A) and interpretative line drawing (B) of the cranium of Lishulong wangi in right lateral view. Image credit: Wei Gao.
Lishulong wangi roamed the supercontinent Laurasia during the Early Jurassic epoch, approximately 193 million years ago.
This new species was a non-sauropodan sauropodomorph dinosaur within the clade Massopoda.
“Non-sauropodan sauropodomorphs were the dominant group of herbivores from the Norian age (227 to 208 million years ago) until the end of the Early Jurassic (175 million years ago), when they were replaced by sauropods,” said Dr. Qian-Nan Zhang, a paleontologist with the Institute of Vertebrate Paleontology and Paleoanthropology and the Nanjing Institute of Geology and Palaeontology at the Chinese Academy of Sciences, and colleagues.
“Since Thecodontosaurus was first established, over 40 valid genera of non-sauropodan sauropodomorphs have been reported worldwide.”
“Most of these genera were identified from Gondwana, mainly recovered in South America and southern Africa.”
“The Early Jurassic epoch was a crucial period in tracking the early radiation and diversification of sauropodomorph dinosaurs,” they added.
“Nearly all the non-sauropodan sauropodomorphs currently recovered in China are reported from Yunnan province, and the Early Jurassic Lufeng Formation is the richest fossil-bearing Mesozoic unit in the province.”
“Although these Lufeng materials are well preserved, and the abundance is high, they are under-represented in comparative studies and cladistic analyses, especially the rare skulls.”
Lishulong wangi’s partial skeleton was recovered from the upper-middle part of the Shawan Member of the Lufeng Formation near Jiudu Village in Yunnan province, China.
The specimen includes the cranium and mandible, and nine articulated cervical vertebrae.
“This new species differs from other Lufeng forms in both cranial and cervical characteristics,” the paleontologists said.
“It bears several autapomorphies of the nasal process, the maxillary neurovascular foramen, and the cervical neural spine.”
The team’s phylogenetic analysis reveals that Lishulong wangi is the sister-species of Yunnanosaurus.
“Lishulong wangi has the largest skull among the abundant sauropodomorph members from the Lufeng Formation,” the researchers said.
“Therefore, it provides a reconsideration for phylogenetic analyses using individual specimens of ascertainable ontogenetic stages as operational taxonomic units to obtain better resolution in general.”
“Our research provides new insights into previous authors dealing with the anatomy of those Lufeng species, representing the first step towards a re-evaluation of this famous dinosaur fauna.”
“Moreover, the paleobiodiversity of early sauropodomorphs from Gondwana seems to decrease marginally after the Triassic-Jurassic boundary.”
“Therefore, we hypothesize that non-sauropodan sauropodomorph genera survived and rapidly radiated in Laurasia, especially China.”
“Furthermore, the ancestral area reconstruction for Lufeng sauropodomorphs is temporarily ambiguous.”
“However, the results of multiple dispersions and exchanges can explain the continuing diversification superiority of non-sauropodan sauropodomorphs from the Lufeng Formation.”
“The limited paleobiogeographic information available from Lishulong wangi provides evidence that at least the initial sauropodiform lineages that are closely related to near-Sauropoda or Sauropoda existed in southwestern China during the Early Jurassic epoch.”
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Q. Zhang et al. 2024. The largest sauropodomorph skull from the Lower Jurassic Lufeng Formation of China. PeerJ 12: e18629; doi: 10.7717/peerj.18629
Source : Breaking Science News