AI Article Synopsis
- Evidence of dinosaur reproduction before the Cretaceous is sparse, but new findings from the Lower Jurassic in southwestern China shed light on this topic.
- The discovery includes three adult skeletons and five egg clutches of a new sauropodomorph, featuring unique reproductive traits like large, thick-shelled eggs and synchronized hatching.
- These fossils indicate that the earliest dinosaur eggs were likely leathery and elliptical, marking a significant evolutionary shift in egg morphology occurring early in theropod evolution, rather than later with the birds.
Article 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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| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC11067957 | PMC |
| http://dx.doi.org/10.1093/nsr/nwad258 | DOI Listing |
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