The earliest normal flower from Liaoning Province, China

Area of Science:

• Paleobotany
• Evolutionary Biology
• Early Cretaceous Flora

Background:

• The early evolution of angiosperms is a long-standing research area.
• The Yixian Formation is known for early angiosperm fossils like Archaefructus and Sinocarpus.
• No definitive normal flower fossils older than 125 million years (Ma) have been found.

Purpose of the Study:

• To report the discovery of the earliest known normal flower fossil.
• To describe the morphology and significance of this new fossil.

Main Methods:

• Fossil discovery and excavation from the Yixian Formation.
• Detailed morphological analysis of the fossil flower.
• Comparative analysis with known early angiosperm fossils.

Main Results:

• Discovery of Callianthus dilae gen. et sp. nov., the earliest normal flower to date.
• Callianthus exhibits typical floral structures: tepals, androecium, and gynoecium.
• The fossil demonstrates a complex floral organization, including specific stamen and carpel features.

Conclusions:

• Callianthus dilae pushes back the date for normal flower evolution.
• The diversity of angiosperms in the Yixian Formation suggests a longer evolutionary history than previously accepted.
• This finding challenges current timelines for angiosperm diversification.