''Leithia'' is a genus of

extinct Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...

giant

dormice A dormouse is a rodent of the family Gliridae (this family is also variously called Myoxidae or Muscardinidae by different taxonomists). Dormice are nocturnal animals found in Africa, Asia, and Europe. They are named for their long, dormant hibe ...

from the

Mediterranean The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the e ...

islands of

Malta Malta ( , , ), officially the Republic of Malta ( mt, Repubblika ta' Malta ), is an island country in the Mediterranean Sea. It consists of an archipelago, between Italy and Libya, and is often considered a part of Southern Europe. It lies ...

and

Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

. It is considered an example of

island gigantism Island gigantism, or insular gigantism, is a biological phenomenon in which the size of an animal species isolated on an island increases dramatically in comparison to its mainland relatives. Island gigantism is one aspect of the more general "i ...

. ''Leithia melitensis'' is the largest known species of dormouse, living or extinct, being twice the size of any other known species.

Discovery and taxonomy

The species were first named by

Andrew Leith Adams Andrew Leith Adams FRSE, FRS (21 March 1827 – 29 July 1882) was a Scottish physician, naturalist and geologist. He was the father of the writer Francis Adams.Gaston, A. J. in Oxford Dictionary of National Biography. Volume 1. pp. 222–223 ...

in 1863 from remains found in caves in Malta and were assigned to the living genus ''

Myoxus The European edible dormouse or European fat dormouse (''Glis glis'') is a large dormouse and one of only two living species in the genus ''Glis'', found in most of Europe and parts of western Asia. Its name comes from the Romans, who ate them as ...

.''Adams, A. L. (1863), ‘Observations on the Fossiliferous caves of Malta’. ''Journal of the Royal Society,'' 4 .2. pp.11–19. ''Leithia'' was proposed in 1896 by

Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was an English naturalist, geologist and writer of numerous books on natural history. Biography Richard Lydekker was born at Tavistock Square in London. His father was Gerard Wolfe Lydekker, ...

as a new genus, suggesting an arrangement currently recognised as the subfamily

Leithiinae Leithiinae is a subfamily of dormice. It is named after the ''Leithia'', an extinct genus of giant dormouse from the Pleistocene of Sicily. Classification Subfamily Leithiinae *Genus ''Chaetocauda'' ** Chinese dormouse, ''Chaetocauda sichuanensi ...

; the names honour Leith Adams. It is estimated to have weighed up to . In the time before the

islands were colonised by humans, dozens of mammal species

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the area, some unusually large like ''Leithia'', some unusually small (such as pygmy elephants and hippopotamuses) lived in

and

Sicily (man) it, Siciliana (woman) , population_note = , population_blank1_title = , population_blank1 = , demographics_type1 = Ethnicity , demographics1_footnotes = , demographi ...

, while another giant dormouse, ''

Hypnomys ''Hypnomys'', otherwise known as Balearic giant dormice, is an extinct genus of dormouse (Gliridae) in the subfamily Leithiinae. Its species are considered examples of insular gigantism. They were endemic to the Balearic Islands in the western Med ...

'', lived on

Mallorca Mallorca, or Majorca, is the largest island in the Balearic Islands, which are part of Spain and located in the Mediterranean. The capital of the island, Palma, is also the capital of the autonomous community of the Balearic Islands. The Bal ...

to the west. In an instance of

, 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. Two species of ''Leithia'', namely ''Leithia melitensis'' (the Maltese giant dormouse) and the smaller ''L. cartei'', lived in Sicily and Malta. (in Italian) The skull of ''L. melitensis'' was 10 cm long.

Evolutionary history

''Leithia'' is already present in the

Early Pleistocene The Early Pleistocene is an unofficial sub-epoch in the international geologic timescale in chronostratigraphy, being the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time ...

(late

Villafranchian Villafranchian age ( ) is a period of geologic time (3.5–1.0 Ma) spanning the Late Pliocene and Early Pleistocene used more specifically with European Land Mammal Ages. Named by Italian geologist Lorenzo Pareto for a sequence of terrestrial s ...

) faunal complex of "Monte Pellegrino", Sicily's oldest faunal complex. It is assumed that ''Leithia'' arrived in Sicily during the

Late Miocene The Late Miocene (also known as Upper Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages. The Tortonian and Messinian stages comprise the Late Miocene sub-epoch, which lasted from 11.63 Ma (million ye ...

(

Messinian The Messinian is in the geologic timescale the last age or uppermost stage of the Miocene. It spans the time between 7.246 ± 0.005 Ma and 5.333 ± 0.005 Ma (million years ago). It follows the Tortonian and is followed by the Zanclean, the first ...

) or

Pliocene The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58 The closest living relative of ''Leithia'' is assumed to be ''

Eliomys ''Eliomys'' ( grc-gre, Ἡλίομυς ''Hēlíomus'') is a genus of rodent in the family Gliridae. It contains the following extant species: * Asian garden dormouse, ''Eliomys melanurus'' * Maghreb garden dormouse, ''Eliomys munbyanus'' * Gard ...

'', based on morphological similarities. ''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.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.

References

{{Taxonbar, from=Q2406274 Dormice Pleistocene rodents Pleistocene mammals of Europe Fossil taxa described in 1896 Rodent genera Taxa named by Richard Lydekker

Discovery and taxonomy

Evolutionary history

See also

References