The fossil record of crocodyliform eggs, eggshells, and nests: a deep-time synthesis and evolutionary perspective
Year: 2026
Type: article
Abstract: Crocodyliform eggs, eggshells, and nests provide essential data regarding reproductive biology, nesting behaviour, and ecological adaptations across deep time. Unlike skeletal remains, eggs and nests remain relatively scarce and have historically received limited attention in palaeobiological research. The fossil record of crocodyliform reproductive structures is overrepresented in Upper Cretaceous localities in Europe and North America. We compile and critically reassess crocodyliform reproductive evidence spanning from the Early Jurassic to the Pliocene. This addresses long-standing geographical and temporal biases. Crocodyliform eggshell microstructure demonstrates evolutionary conservatism. It retains characteristic features, such as wedge-shaped eggshell units, basal knobs, and tabular ultrastructure, since the Jurassic. However, subtle morphological variations, including crystal organisation, ornamentation, porosity, and eggshell thickness, suggest ecological flexibility and possible lineage-specific adaptations. The deep-time record of crocodylomorph reproduction has important implications for modern conservation. Crocodyliforms rely on specific nesting conditions, which makes them vulnerable to anthropogenic pressures, despite demonstrated resilience through major environmental changes and extinction crises. Understanding evolutionary stability and environmental requirements of past crocodyliform nesting behaviour is essential for informing management strategies to protect breeding habitats.
Source: Historical Biology
Authors: Xavier Panades, Àngel Galobart, Albert Sellés
Language: English
Subfield: Paleontology
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7212450956
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