Researchers have confirmed, based on the dental enamel of horse fossils, that in the Upper Myocenic, approximately 9 million years ago, climate change occurred in the Iberian Peninsula, which caused a sharper contrast between seasons of the year.
© Lusa
27/10/2026
by
Lusa
Iinvestigators confirmed, based on dental enamel of fossils of horses, that in the Myocenic Superior, approximately 9 million years ago, there was a climate change in the Iberian Peninsula, which caused a sharper contrast between seasons of the year.
The article, which has the participation of researchers from the National Museum of Natural Sciences (MNCN-CSIC) in Spain, was published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology.
This work, led by the Complutense University of Madrid (UCM) and which also has the participation of the Institute of Geosciences (ICEO, CSIC-UCM), describes fossil remains from two sites in the centre of the Iberian Peninsula: Valles de Fuentidueña, in the province of Segovia (the Douro Basin), dated 9.6 million years ago; and Batallones-10 (the Madrid Basin), dated 9.1 million years ago.
The results showed that the animals of Batallones-10 experienced a much more pronounced seasonal variability than those found at the site of Segovia.
“ This difference suggests that during this interval of approximately half a million years, there was an intensification of seasonality, probably related to more striking contrasts in temperatures or water availability ", explained Dánae Sanz Pérez, a researcher at the MCU at the time of the study.
This change coincides with the so-called “Crisis do Vallesiano”, an episode of faunistic renewal and transformation of European ecosystems, characterized by the disappearance of mammals associated with forest environments and the reorganization of communities towards fauna adapted to more open and dry conditions.
“ However, despite climate change, individuals from both locations maintained a diet based mainly on type C3 vegetation, characteristic of open forests and pastures. This suggests that changes in seasonality were not necessarily accompanied by significant changes in the diet of these animals,” said Laura Domingo, a researcher at the MCU.
For the study, the researchers analyzed 141 dental enamel samples obtained from eleven Hipparion teeth.
“ After the preparation of fossils, the team used a technique called serial sampling, which consists of the extraction of small amounts of dental enamel at regular intervals along the dental crown,” explains Enrique Cantero, responsible for the MNCN fossil restoration laboratory.
The teeth grow progressively and, during their formation, incorporate chemical information related to the diet and environmental conditions experienced by the animal at that time.
For this reason, analysis of stable oxygen (Delta 180) and carbon (Delta 13C) isotopes enables seasonal variations of climate and diet to be reconstructed, respectively.
The next step will be to extend this type of analysis to other sites on the Iberian Peninsula that allow rebuilding climate and environmental change during the Upper Myocenic, incorporating new locations and other mammalian groups.
The objective is to investigate whether the intensification of seasonality, identified in this study, was a widespread phenomenon and how animals with different ecological strategies may have responded to it.