New species of lizard discovered using neutrons

Researchers at FRM II have used neutrons to identify a previously unknown species of lizard that appears to have been widespread. The fossil, which is around ten million years old, shows that there were significantly more species at that time than previously thought.

Fontisaurus_tarumbaire_CopyrightMichael_Tripoli2 Illustration of the new genus Fontisaurus tarumbaire © Michael Tripoli

Illustration of the new genus Fontisaurus tarumbaire © Michael Tripoli

A changing climate and new land bridges led to an intensive exchange of animal species between Europe and Asia around 11 to 5 million years ago, during the Miocene epoch. The diversity of squamates, which include lizards and snakes, was particularly high during this period – some species, such as the slow worm, are still found in Europe today. However, the true extent of this diversity remained unclear for a long time, as many fossils could only be analysed to a limited extent. Modern imaging techniques now allow for a more accurate reconstruction.

3D analysis using neutron tomography

A team of scientists led by Andrea Villa of the Institut Català de Paleontologia Miquel Crusafont has examined a find from northern Spain using the ANTARES neutron imaging facility at FRM II.

Burkhard Schillinger The ANTARES neutron imaging facility, pictured here with instrument scientist Dr Burkhard Schillinger, enables a particularly high contrast between the sample and the sediment © Bernhard Ludewig, FRM II / TUM

The ANTARES neutron imaging facility, pictured here with instrument scientist Dr Burkhard Schillinger, enables a particularly high contrast between the sample and the sediment © Bernhard Ludewig, FRM II / TUM

“The advantage of neutron tomography lies in the high, material-specific contrast, which makes it easier to distinguish between bone and sediment than with X-rays,” explains FRM II instrument scientist and co-author of the study Dr Burkhard Schillinger.

Neutrons reveal bone structure

High-resolution neutron tomography provided a three-dimensional view of the animal’s bone structure. “What is special is that it is an almost complete skull. In comparison, many fossils are usually found only as fragments,” explains lead author Andrea Villa. The parietal bone – a bone in the upper rear part of the skull – in particular exhibits characteristic morphological features that allow for a clear taxonomic distinction from previously known species.

Church Viladecavalls The church in Viladecavalls, located near the site where the fossil was found © Frederic Pahisa/Viladecavalls Town Council

The church in Viladecavalls, located near the site where the fossil was found © Frederic Pahisa/Viladecavalls Town Council

Dragon guarding the spring

The research team classified the find as a new species: Fontisaurus tarumbaire. The genus name ‘Fontisaurus’ is derived from the Latin ‘fons’ (spring, genitive ‘fontis’) and the Greek ‘sauros’ (lizard). It refers to the legend from Viladecavalls, according to which every spring in the area is guarded by a small dragon. The specific epithet tarumbaire comes from Catalan and is the colloquial term for the inhabitants of Viladecavalls, the municipality where the fossil was found.

A similar parietal bone has been found in Germany, suggesting a wider geographical distribution of this species.

New picture of biodiversity

The discovery sheds new light on the evolution of these lizards in Europe. “It shows that their diversity was probably greater than previously thought and provides a clearer picture of the continent’s prehistoric ecosystems,” explains Andrea Villa. This could help to identify other fossils more accurately in the future.