Leithia is a genus of extinct giant dormice from the Mediterranean islands of Malta and Sicily. It is considered an example of island gigantism. Leithia melitensis is the largest known species of dormouse, living or extinct, being twice the size of any other known species.

Temporal range: Early Pleistocene–Late Pleistocene
Leithia melitensis skull.jpg
Model of the skull of L. melitensis
Scientific classification e
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Gliridae
Subfamily: Leithiinae
Genus: Leithia
Lydekker, 1896[1]
Type species
Myoxus melitensis Adams, 1863[2]
  • Leithia melitensis (Adams, 1863)
  • Leithia cartei (Adams, 1863)

Discovery and taxonomyEdit

Leithia melitensis skeleton

The species were first named by Andrew Leith Adams in 1863 from remains found in caves in Malta and were assigned to the living genus Myoxus.[2] Leithia was proposed in 1896 by Richard Lydekker as a new genus, suggesting an arrangement currently recognised as the subfamily Leithiinae; the names honour Leith Adams.[1][3] It is estimated to have weighed up to 113 g (4.0 oz). In the time before the Mediterranean islands were colonised by humans, dozens of mammal species endemic to the area, some unusually large like Leithia, some unusually small (such as pygmy elephants and hippopotamuses) lived in Malta and Sicily, while another giant dormouse, Hypnomys, lived on Mallorca to the west. In an instance of island gigantism, the dormice were able to grow large in the absence of predators on these islands, which otherwise force rodents to hide in holes or cracks, requiring them to be small.[4] Two species of Leithia, namely Leithia melitensis (the Maltese giant dormouse) and the smaller L. cartei, lived in Sicily and Malta.[5] The skull of L. melitensis was 10 cm long.[6]

Evolutionary historyEdit

Leithia is already present in the Early Pleistocene (late Villafranchian) faunal complex of "Monte Pellegrino", Sicily's oldest faunal complex. It is assumed that Leithia arrived in Sicily during the Late Miocene (Messinian) or Pliocene, but this is not preserved in the fossil record.[7] The closest living relative of Leithia is assumed to be Eliomys, based on morphological similarities.[8] Leithia became extinct during the Late Pleistocene as part of a faunal turnover event caused by the uplift of Calabria and Sicily causing a closer connection with the Italian mainland, which during the low sea levels of the last glacial cycle allowed the mainland fauna of Italy to invade Sicily, coinciding with the extinction of most endemic species.[7]

See alsoEdit


  1. ^ a b Lydekker, Richard (1895). "On the affinities of the so called extinct giant dormouse of Malta". Proceedings of the Zoological Society of London: 860–863.
  2. ^ a b Adams, A. L. (1863),  ‘Observations on the Fossiliferous caves of Malta’. Journal of the Royal Society, 4 .2. pp.11–19.
  3. ^ Wilson, Don E.; Reeder, DeeAnn M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference, Volume 12. JHU Press. p. 829.
  4. ^ Davis, Simon (3 January 1985). "Tiny Elephants and Giant Mice". New Scientist: 25–27.
  5. ^ Petronio, C. (1970). "I Roditori Pleistocenici della Grotta di Spinagallo (Siracusa)" (PDF). Geol. Rom. IX: 149–194. (in Italian)
  6. ^ Davis, Simon (1987). The Archaeology of Animals. Psychology Press. pp. 120–121.
  7. ^ a b Bonfiglio, L., Marra, A. C., Masini, F., Pavia, M., & Petruso, D. (2002). Pleistocene faunas of Sicily: a review. In W. H. Waldren, & J. A. Ensenyat (Eds.), World islands in prehistory: international insular investigations. British Archaeological Reports, International Series, 1095, 428–436.
  8. ^ Hennekam, Jesse J.; Herridge, Victoria L.; Costeur, Loïc; Patti, Carolina Di; Cox, Philip G. (2020-07-03). "Virtual Cranial Reconstruction of the Endemic Gigantic Dormouse Leithia melitensis (Rodentia, Gliridae) from Poggio Schinaldo, Sicily". Open Quaternary. 6 (1): 7. doi:10.5334/oq.79. ISSN 2055-298X.