Researcher reconstructs skull of two million year-old giant dormouse

July 09, 2020

A PhD student has produced the first digital reconstruction of the skull of a gigantic dormouse, which roamed the island of Sicily around two million years ago.

In a new study, the student from Hull York Medical School, has digitally pieced together fossilised fragments from five giant dormouse skulls to reconstruct the first known complete skull of the species.

The researchers estimate that the enormous long-extinct rodent was roughly the size of a cat, making it the largest species of dormouse ever identified.

The digitally reconstructed skull is 10 cm long - the length of the entire body and tail of many types of modern dormouse.

PhD student Jesse Hennekam said: "Having only a few fossilised pieces of broken skulls available made it difficult to study this fascinating animal accurately. This new reconstruction gives us a much better understanding of what the giant dormouse may have looked like and how it may have lived."

The enormous prehistoric dormouse is an example of island gigantism - a biological phenomenon in which the body size of an animal isolated on an island increases dramatically.

The palaeontological record shows that many weird and wonderful creatures once roamed the Italian islands. Alongside the giant dormouse, Sicily was also home to giant swans, giant owls and dwarf elephants.

Jesse's PhD supervisor, Dr Philip Cox from the Department of Archaeology at the University of York and Hull York Medical School, said: "While Island dwarfism is relatively well understood, as with limited resources on an island animals may need to shrink to survive, the causes of gigantism are less obvious.

"Perhaps, with fewer terrestrial predators, larger animals are able to survive as there is less need for hiding in small spaces, or it could be a case of co-evolution with predatory birds where rodents get bigger to make them less vulnerable to being scooped up in talons."

Jesse spotted the fossilised fragments of skull during a research visit to the Palermo Museum in Italy, where a segment of rock from the floor of a small cave, discovered during the construction of a motorway in northwest Sicily in the 1970s, was on display.

"I noticed what I thought were fragments of skull from an extinct species embedded in one of the cave floor segments", Jesse said. "We arranged for the segment to be sent to Basel, Switzerland for microCT scanning and the resulting scans revealed five fragmented skulls of giant dormice present within the rock."

The reconstruction is likely to play an important role in future research directed at improving understanding of why some small animals evolve larger body sizes on islands, the researchers say.

"The reconstructed skull gives us a better sense of whether the giant dormouse would have looked similar to its normal-sized counterparts or whether its physical appearance would have been influenced by adaptations to a specific environment", Jesse explains.

"For example, if we look at the largest living rodent - the capybara - we can see that it has expanded in size on a different trajectory to other species in the same family."

Jesse is also using biomechanical modelling to understand the feeding habits of the giant dormouse.

"At that size, it is possible that it may have had a very different diet to its smaller relatives," he adds.
-end-
Virtual Cranial Reconstruction of the Endemic Gigantic Dormouse Leithia melitensis (Rodentia, Gliridae) from Poggio Schinaldo, Sicily is published in Open Quaternary. The study was supported by the University of York, Hull York Medical School and the European Federation of Experimental Morphology.

University of York

Related Species Articles from Brightsurf:

A new species of spider
During a research stay in the highlands of Colombia conducted as part of her doctorate, Charlotte Hopfe, PhD student at the University of Bayreuth, has discovered and zoologically described a new species of spider.

Two new species of parasite discovered in crabs -- discovery will help prevent infection of other marine species
Two new species of parasite, previously unknown to science, have been discovered in crabs in Swansea Bay, Wales, during a study on disease in the Celtic and Irish Seas.

Marine species are outpacing terrestrial species in the race against global warming
Global warming is causing species to search for more temperate environments in which to migrate to, but it is marine species -- according to the latest results of a Franco-American study mainly involving scientists from the CNRS, Ifremer, the Université Toulouse III-Paul Sabatier and the University of Picardy Jules Verne -- that are leading the way by moving up to six times faster towards the poles than their terrestrial congeners.

Directed species loss from species-rich forests strongly decreases productivity
At high species richness, directed loss, but not random loss, of tree species strongly decreases forest productivity.

What is an endangered species?
What makes for an endangered species classification isn't always obvious.

One species, many origins
In a paper published in Nature Ecology and Evolution, a group of researchers argue that our evolutionary past must be understood as the outcome of dynamic changes in connectivity, or gene flow, between early humans scattered across Africa.

Species on the move
A total of 55 animal species in the UK have been displaced from their natural ranges or enabled to arrive for the first time on UK shores because of climate change over the last 10 years (2008-2018) -- as revealed in a new study published today by scientists at international conservation charity ZSL (Zoological Society of London).

Chasing species' 'intactness'
In an effort to better protect the world's last ecologically intact ecosystems, researchers developed a new metric called 'The Last of the Wild in Each Ecoregion' (LWE), which aimed to quantify the most intact parts of each ecoregion.

How do species adapt to their surroundings?
Several fish species can change sex as needed. Other species adapt to their surroundings by living long lives -- or by living shorter lives and having lots of offspring.

Five new frog species from Madagascar
Scientists at Ludwig-Maximilians-Universitaet in Munich and the Bavarian State Collection of Zoology have named five new species of frogs found across the island of Madagascar.

Read More: Species News and Species Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.