A team of researchers from the CONICET unearthed a tiny flower in the northwest of San Luis that rewrites the botanical history of the country. It is Stellula meridionalis —”little southern star” in Latin—, the oldest fossil flower ever found in Argentina, with an estimated age of 113 million years, corresponding to the late Aptian of the early Cretaceous.
The discovery, published in Scientific Reports and led by Dr. Griselda Puebla, a researcher from IANIGLA (CONICET-UNCUYO), fills an important evolutionary gap and challenges current theories about the dispersion of flowering plants in Gondwana, the ancient supercontinent that included South America.
“It’s like finding a needle in a paleontological haystack”, stated Puebla. Until now, only Brazil had recorded such ancient floral fossils in the region; in Argentina, records were limited to isolated pollen or leaves, without complete floral structures.
A tiny structure, but with great evolutionary impact
The flower was found in the La Cantera Formation, an ancient system of ephemeral lagoons with fluvial environments, where fine sedimentation allowed exceptional preservation. The fossil includes:
- A 3-centimeter stem with opposite leaves and flowers.
- Serrated leaves of 3 mm, similar to those of certain modern eudicots.
- Star-shaped flowers less than 1 cm, with two rows of triangular structures resembling a star.
- Associated pollen grains, indicating a diverse plant ecosystem.
According to the team, the flowers would be unisexual and female, as no visible male reproductive structures were detected. These characteristics support the definition of a new genus and species of angiosperm.
A valuable piece in the floral evolution puzzle
The origin of angiosperms (flowering plants) remains an evolutionary enigma. Although some studies suggest they emerged long before the Cretaceous, well-preserved floral fossils are extremely rare. Therefore, the discovery of Stellula meridionalis offers concrete clues about the early evolution and diversification of flowers, especially in Gondwana.
The pollen found in the surroundings, although not directly linked to the fossil flowers, provided information that allowed linking Stellula to ancestral groups such as Ranunculales, from which current species like ranunculus derive.
National science in the service of natural history
This discovery not only represents a remarkable scientific advancement but also highlights the key role of Conicet and Argentine paleobotany in the global understanding of ancient ecosystems.
Each fossil flower is a window into the deep past of terrestrial life, and Stellula meridionalis already shines as a tiny yet fundamental star in the firmament of evolutionary science.
