Skull of two million year-old giant dormouse reconstructed

Date:
July 9, 2020
Source:
University of York
Summary:
A researcher has digitally pieced together fossilized fragments
from five giant dormouse skulls to reconstruct the first known
complete skull of the species, which was roughly the size of a cat.



FULL STORY ==========================================================================
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.


========================================================================== Story Source: Materials provided by University_of_York. Note: Content
may be edited for style and length.


========================================================================== Journal Reference:
1. Jesse J. Hennekam, Victoria L. Herridge, Loi"c Costeur, Carolina Di
Patti, Philip G. Cox. Virtual Cranial Reconstruction of the
Endemic Gigantic Dormouse Leithia melitensis (Rodentia, Gliridae)
from Poggio Schinaldo, Sicily. Open Quaternary, 2020; 6 DOI:
10.5334/oq.79 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/07/200709105116.htm

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