The new species, 'Marmoretta drescherae', belongs to the genus 'Marmoretta', which "represents the primitive branch of the evolutionary tree of modern lizards", says in a statement the Faculty of Science and Technology (FCT) of UNL, where Alexandre Guillaume conducted the study as part of his doctorate.

So far only one species belonging to the genus 'Marmoretta', 'Marmoretta oxoniensis', has been referenced.

"The 'Marmoretta drescherae' is not a direct ancestor of current lizards, but rather a primitive representative of a lineage that became extinct at the end of the Jurassic", highlights Alexandre Guillaume, quoted in the FCT/UNL statement, adding that the "discovery reinforces the hypothesis that, at the end of the Jurassic, North America, Europe and Northwest Africa shared similar faunas, while also suggesting local ecological differences".

For this study, carried out in collaboration with researchers from the Spanish University of Zaragoza, paleontologist Alexandre Guillaume analyzed 150 fossils stored at the Geological Museum in Lisbon, which had been found in the Guimarota mine in Leiria, "one of the richest deposits of microfossils from the Upper Jurassic".

Based on the analysis of Portuguese fossils, by comparison with fossils found in the United Kingdom and the United States, the work led by Alexandre Guillaume also confirmed the presence in the Jurassic fauna of Portugal of a small semi-aquatic reptile belonging to the genus 'Cteniogenys', although "without being able to determine whether it is a different species from those already described in other regions".

Alexandre Guillaume, who studies the small herpetofauna (reptiles and amphibians) of the Upper Jurassic of Portugal, and the rest of the team analysed isolated fragments of jaws, skulls, limbs and vertebrae.

The research, which aimed to re-evaluate fossils described in the 1970s and 1990s by palaeontologists at the Free University of Berlin in Germany, was published in the open-access scientific journal Acta Palaentologica Polonica.