First evidence of monitor lizards in Switzerland

 (Image: Pixabay CC0)
(Image: Pixabay CC0)

After a chance discovery in the collection’s repository, a Basel researcher provides the first evidence of the existence of monitor lizards in Switzerland. While working in the vertebrate fossil collection at Basel’s Natural History Museum, paleontologist Bastien Mennecart’s eye was caught by two teeth of a large lizard. The fossils come from near Langnau in the canton of Bern. The serrations on the teeth and their interiors are typical of monitor lizards. This is the first evidence that monitor lizards also lived in Switzerland 17 million years ago. The results of this discovery were published yesterday in the renowned scientific journal Swiss Journal of Geoscience.

During his scientific work, paleontologist Bastien Mennecart discovered two remarkable incomplete teeth among the hundreds of small fossil bones and teeth in the vertebrate paleontological collection at the Basel Natural History Museum. He discovered that they were the teeth of a large lizard. Working with an international team of three researchers from Poland, Germany and Switzerland, the discovery was described in detail. The research group concluded that the teeth were the first evidence of a monitor lizard that lived in Switzerland 17 million years ago. At that time, the temperature in Switzerland was 5 to 10 degrees warmer than today. Although there is a stock of fossils from this period, no monitor was known to have originated in Switzerland at this time either. The fossil teeth are among the earliest evidence of the giant Varanus lizard known in Europe. The last known European monitor lizards lived in Greece less than a million years ago.

The first proof

The newly-discovered fossils come from the Hüenerbach in Emmental, Canton Bern, a stream near Langnau. The scientists gathered around Mennecart found that one of the specimens had pronounced, knife-like teeth, while the characteristic morphology of the inside of the tooth, known as the pulp cavity, displays features typical of the dentition of modern monitor lizards. For Georgios Georgalis, paleontologist at the Institute of Systematics and Evolution of Animals of the Polish Academy of Sciences in Krakow, the small fossil remains are of vital importance. "Bastien Mennecart is well aware of the importance of the Basel Natural History Museum’s paleontological collection of vertebrate fossils. It is one of the largest collections of its kind in Europe, and is known the world over by specialists. "The paleontological collection is full of treasures," said Mennecart. "We are intensively preparing the collections for the move to the new museum. Who knows what other surprises await us there?".

The world’s largest ground lizard

Komodo dragons are among the world’s largest land lizards still alive today. They can reach up to three meters in length. One of their ancestors, the famous Megalania, measured up to seven meters long. This Australian species became extinct around 45,000 years ago. Today, around 85 different species of monitor lizards are known. They are widely distributed, occupying different habitats in Africa, Asia and Australia. The oldest known varan species date back to the early Miocene, i.e. around 18 million years ago. They lived in Afro-Eurasia and Australia. At present, there are only a few known sites of fossil monitor lizards in Europe. So far, fossil varan remains have been found in the Czech Republic, France and Spain.

Publication: Georgalis G., Mennecart B., & Smith K. (2023) First fossil record of Varanus (Reptilia, Squamata) from Switzerland and the earliest occurrences of the genus in Europe. Swiss Journal of Geosciences
Paper: https://sjg.springeropen.com/articles/10.1186/s00015-023-00440-5