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Han F, Yu Y, Zhang S, Zeng R, Wang X, Cai H, Wu T, Wen Y, Cai S, Li C, Wu R, Zhao Q, Xu X. Exceptional Early Jurassic fossils with leathery eggs shed light on dinosaur reproductive biology. Natl Sci Rev 2024; 11:nwad258. [PMID: 38707200 PMCID: PMC11067957 DOI: 10.1093/nsr/nwad258] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 05/07/2024] Open
Abstract
Our understanding of pre-Cretaceous dinosaur reproduction is hindered by a scarcity of evidence within fossil records. Here we report three adult skeletons and five clutches of embryo-containing eggs of a new sauropodomorph from the Lower Jurassic of southwestern China, displaying several significant reproductive features that are either unknown or unlike other early-diverging sauropodomorphs, such as relatively large eggs with a relatively thick calcareous shell formed by prominent mammillary cones, synchronous hatching and a transitional prehatching posture between the crocodilians and living birds. Most significantly, these Early Jurassic fossils provide strong evidence for the earliest known leathery eggs. Our comprehensive quantitative analyses demonstrate that the first dinosaur eggs were probably leathery, elliptical and relatively small, but with relatively long eggshell units, and that along the line to living birds, the most significant change in reptilian egg morphology occurred early in theropod evolution rather than near the origin of Aves.
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Affiliation(s)
- Fenglu Han
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Yilun Yu
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
- University of Chinese Academy of Sciences, Beijing 101408, China
| | - Shukang Zhang
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
| | - Rong Zeng
- Guizhou Provincial Museum, Guiyang 550081, China
| | - Xinjin Wang
- Guizhou Provincial Institute of Cultural Relics and Archaeology, Guiyang 550001, China
| | - Huiyang Cai
- Guizhou Provincial Museum, Guiyang 550081, China
| | | | - Yingfeng Wen
- Pingba Institute of Cultural Relics Administration, Anshun 550820, China
| | - Sifu Cai
- Guizhou Provincial Museum, Guiyang 550081, China
| | - Chun Li
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
| | - Rui Wu
- School of Earth Sciences, China University of Geosciences (Wuhan), Wuhan 430074, China
| | - Qi Zhao
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
| | - Xing Xu
- Centre for Vertebrate Evolutionary Biology, Yunnan University, Kunming 650091, China
- Key Laboratory of Vertebrate Evolution and Human Origins, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China
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Peyre de Fabrègues C, Bi S, Li H, Li G, Yang L, Xu X. A new species of early-diverging Sauropodiformes from the Lower Jurassic Fengjiahe Formation of Yunnan Province, China. Sci Rep 2020; 10:10961. [PMID: 32620800 PMCID: PMC7335049 DOI: 10.1038/s41598-020-67754-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 05/26/2020] [Indexed: 12/11/2022] Open
Abstract
Sauropodomorpha were herbivorous saurischian dinosaurs that incorporate Sauropoda and early-diverging sauropodomorphs. The oldest sauropodomorph remains are known from Late Triassic deposits, most of them Gondwanan. The Laurasian record comprises some Triassic forms, but the bulk is Jurassic in age. Among the 14 Jurassic non-sauropodan sauropodomorphs from Laurasia described in the past, 8 are from China. Here we describe a new non-sauropodan sauropodomorph, Irisosaurus yimenensis gen. et sp. nov., from the Early Jurassic Fengjiahe Formation of China. Nearly all of the non-sauropodan sauropodomorph genera currently known from China were first reported from the Lufeng Formation. The Fengjiahe Formation is its Southern equivalent, bringing a fauna similar to that of the Lufeng Formation to light. The new genus is defined based on an incomplete but unique maxilla, with a premaxillary ramus higher than long prior to the nasal process, a large and deep neurovascular foramen within the perinarial fossa, and a deep perinarial fossa defined by a sharp rim. Phylogenetic analysis places Irisosaurus at the very base of Sauropodiformes, as the sister-taxon of the Argentinean genus Mussaurus. This specimen adds to a growing assemblage of Chinese Jurassic non-sauropodan sauropodomorphs that offers new insight into the Laurasian evolution of this clade.
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Affiliation(s)
- Claire Peyre de Fabrègues
- Centre for Vertebrate Evolutionary Biology, Institute of Palaeontology, Yunnan University, Kunming, 650091, China.
| | - Shundong Bi
- Centre for Vertebrate Evolutionary Biology, Institute of Palaeontology, Yunnan University, Kunming, 650091, China
- Department of Biology, Indiana University of Pennsylvania, Indiana, PA, 15705, USA
| | - Hongqing Li
- Centre for Vertebrate Evolutionary Biology, Institute of Palaeontology, Yunnan University, Kunming, 650091, China
| | - Gang Li
- Centre for Vertebrate Evolutionary Biology, Institute of Palaeontology, Yunnan University, Kunming, 650091, China
| | - Lei Yang
- Yimen Administration of Cultural Heritage, Yimen, 651100, China
| | - Xing Xu
- Key Laboratory of Evolutionary Systematics of Vertebrates, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing, 100044, China.
- Center for Excellence in Life and Paleoenvironment, Beijing, 100044, China.
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