When Earth started blooming: insights from the fossil record

Area of Science:

• Palaeobotany
• Evolutionary Biology
• Phylogenetics

Background:

• Recent palaeobotanical studies have enhanced understanding of Cretaceous angiosperm structure and relationships.
• Well-preserved fossil flowers and molecular phylogenetic analyses have clarified early angiosperm diversification.
• However, the phylogenetic origin of angiosperms and relationships among extant seed plant groups remain uncertain.

Purpose of the Study:

• To synthesize current knowledge on Cretaceous angiosperms from palaeobotanical and molecular data.
• To identify persistent questions regarding angiosperm origins, diversification, and the impact of extinction.
• To highlight areas for future palaeobotanical research.

Main Methods:

• Analysis of palaeobotanical data, focusing on exceptionally preserved Cretaceous flowers.
• Integration of molecular sequence data from extant angiosperms for phylogenetic analyses.
• Comparison of molecular clock divergence estimates with the fossil record.

Main Results:

• A significant portion of angiosperm diversity, particularly during the Cretaceous, is now known to be extinct.
• Some fossil angiosperms do not fit into extant families, suggesting extinct lineages.
• Extinction has likely skewed our understanding of early angiosperm evolution based on extant taxa alone.

Conclusions:

• Evolutionary studies relying solely on extant taxa may be misled by extinction patterns.
• Enigmatic early angiosperm fossils could represent lineages diverging before the most recent common ancestor of extant taxa.
• Future palaeobotanical research is crucial for resolving remaining questions about angiosperm evolution.