Maltese Giant Dormouse

A team of paleontologists has created the first digital reconstruction of the skull of the Maltese Giant Dormouse (Leithia melitensis), an extinct gigantic dormouse that lived on Malta and Sicily around two million years ago[1]. A closely related species, the somewhat smaller Sicilian Giant Dormouse (Leithia cartei), lived on nearby Sicily.

The Maltese Giant Dormouse was first described by the Scottish naturalist Andrew Leith Adams in 1863. The genus was later named in his honour.

Roughly the size of a cat, the ancient rodent is by far the largest known dormouse species, being at least twice the size of any other insular species both extant and extinct.

The Maltese Giant Dormouse is an example of island gigantism, a biological phenomenon in which the body size of an animal isolated on an island increases dramatically.

Besides the gigantic dormice, the Mediterranean islands of Malta, Gozo and Sicily were also home to giant swans and owls as well as dwarf deer, hippos and elephants.

“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,” said senior author Dr. Philip Cox. “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.”

In the new study, the scientists digitally pieced together fossilized fragments from five skulls of the Maltese Giant Dormouse to reconstruct the first complete skull of the species. The reconstructed skull is 10 centimetres long — the length of the entire body and tail of many types of modern dormouse.

“Having only a few fossilized pieces of broken skulls available made it difficult to study this fascinating animal accurately,” explained lead author Jesse Hennekam. “This new reconstruction gives us a much better understanding of what the giant dormouse may have looked like and how it may have lived.”

[1] Hennekam et al: Virtual Cranial Reconstruction of the Endemic Gigantic Dormouse Leithia melitensis (Rodentia, Gliridae) from Poggio Schinaldo, Sicily in Open Quaternary - 2020. See here.