The Oldest Fossil Flower Found in San Luis, Argentina
A team of CONICET scientists discovered in the province of San Luis the oldest fossil flower recorded in Argentina so far.
It is a new species of angiosperm (flowering plants) named Stellula meridionalis, which lived approximately 113 million years ago, during the Late Aptian Early Cretaceous period.
The Fossil Flower Found in San Luis: The Oldest Known in Argentina
The discovery was made in the La Cantera geological formation, in the northwest of San Luis, and represents a significant advance in the knowledge of plant evolution in South America.
Until now, in Argentina, only fossils of leaves and pollen grains from this ancient period had been found. Only in Brazil are there similar Cretaceous flower records on the continent.
“Stellula meridionalis is the oldest fossil flower in Argentina. It is a key discovery, as a well-preserved flower of this age had never been found in our country,” explained Griselda Puebla, a CONICET researcher at the Institute of Snow, Glaciers, and Environmental Sciences (IANIGLA, CONICET–UNCUYO–Gob. Mza.).
The flower was identified from a set of specimens that include stems, leaves, and over twenty flowers in various stages of maturation.
The stem is about three centimeters long and has leaves and flowers arranged in an opposite manner towards its end.
The leaves are small and toothed, measuring approximately three millimeters long. The flowers have a conical base and two rows of triangular structures arranged in a star shape, which inspired its name (Stellula means “little star”).
According to the scientists, these flowers would be unisexual and female, as no male structures were found. The morphological characteristics of the reproductive axis allow classifying Stellula meridionalis as a new genus and species of angiosperm.
How the Fossils Were Detected
They were found in carbonized impressions within fine rocks, formed in ancient lacustrine environments connected to river systems. “The flowers are very fragile, so finding them in such a well-preserved state is truly exceptional,” Puebla noted.
In the same strata, they also found angiosperm pollen grains, allowing the analysis of the botanical affinity of the fossil and establishing evolutionary relationships with current and extinct species.
“This type of fossils is essential to understand the early evolution of flowering plants,” added Mercedes Prámparo, co-author of the study and CONICET researcher at IANIGLA.
The Significance of the Discovery
The discovery reaffirms the paleobotanical value of Argentine fossils for studying the origin and diversification of angiosperms, a key milestone in the biological history of the planet.
According to the scientists, the Early Cretaceous was a crucial moment in the global expansion of these plants that now dominate most terrestrial ecosystems.
