''Leithia'' is an extinct genus of giant

dormice A dormouse is a rodent of the family (biology), 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 ...

from the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

of 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 east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern ...

islands of

Malta Malta, officially the Republic of Malta, is an island country in Southern Europe located in the Mediterranean Sea, between Sicily and North Africa. It consists of an archipelago south of Italy, east of Tunisia, and north of Libya. The two ...

and

Sicily Sicily (Italian language, Italian and ), officially the Sicilian Region (), is an island in the central Mediterranean Sea, south of the Italian Peninsula in continental Europe and is one of the 20 regions of Italy, regions of Italy. With 4. ...

. 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.

Discovery and taxonomy

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.''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 a British naturalist, geologist and writer of numerous books on natural history. He was known for his contributions to zoology, paleontology, and biogeography. He worked extensively in cata ...

as a new genus, suggesting an arrangement currently recognised as the subfamily Leithiinae; the names honour Leith Adams. Two species of ''Leithia'', namely ''Leithia melitensis'' and the smaller ''L. cartei'', lived in Sicily and Malta. (in Italian)

Description

The skull of ''Leithia melitensis'' reached a length of approximately , roughly twice the length of that of the European garden dormouse (''Eliomys quercinus''). ''L. melitensis'' reached a total size comparable to a cat or a rabbit, with an estimated body mass of approximately . Compared to ''Eliomys'', the skull morphology of ''L. melitensis'' is much more robust, particularly the zygomatic region (indicating the presence of large masseter muscles in life) and the pterygoid flange. The rostrum of ''L. melitensis'' relatively short, and the molar teeth are proportionally enlarged relative to ''Eliomys''. The mandible of ''L. melitensis'' is also extremely robust.

Ecology

The teeth of ''Leithia melitensis'' exhibit a variable amount of wear, indicating an abrasive, and probably largely herbivorous diet, with the lower jaw exhibiting greater adaption to chewing rather than gnawing. ''Leithia'' was likely predated upon by large birds of prey native to the islands, such as the endemic large

barn-owl The barn owls, owls in the genus ''Tyto'', are the most Cosmopolitan distribution, widely distributed genus of owls in the world. They are medium-sized owls with large heads and characteristic heart-shaped faces. They have long, strong legs with ...

'' Tyto mourerchauvireae.''

Evolutionary history

The closest living relative of ''Leithia'' is assumed to be '' Eliomys'' (which among others, contains the European garden dormouse) based on morphological similarities. Remains tentively referred to ''Leithia'' are known from the

Early Pleistocene The Early Pleistocene is an unofficial epoch (geology), sub-epoch in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently esti ...

(late Villafranchian) "Monte Pellegrino" faunal complex. However, other authors have suggested that this taxon is instead more closely related to the genus '' Maltamys'', also endemic to Sicily and Malta.Petruso, D. 2004
New data on Pleistocene endemic Sicilian-Maltese dormice (Gliridae, Mammalia).
18th International Senckenberg Conference, VI International Palaeontological Colloquium in Weimar, 205–206. It has been suggested by some that the ancestors ''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 fir ...

) or

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58 For most of the

Middle Pleistocene The Chibanian, more widely known as the Middle Pleistocene (its previous informal name), is an Age (geology), age in the international geologic timescale or a Stage (stratigraphy), stage in chronostratigraphy, being a division of the Pleistocen ...

during the "''Elephas falconeri"'' faunal complex, ''Leithia'' was one of a small number of mammal species present on Sicily and Malta, alongside the dwarf elephant '' Palaeoloxodon falconeri,'' the large dormouse ''Maltamys'', a shrew belonging to the genus ''

Crocidura The genus ''Crocidura'' is one of nine genera of the shrew subfamily Crocidurinae. Members of the genus are commonly called white-toothed shrews or musk shrews, although both also apply to all of the species in the subfamily. With over 180 sp ...

,'' and an otter. During the late Middle Pleistocene a faunal turnover event occurred, caused by the uplift of Calabria and Sicily resulting in a closer connection with the Italian mainland, which during episodes of low sea level allowed some large animals from the mainland fauna of Italy to invade Sicily. ''Leithia'' persisted alongside the new arrivals for some time as demonstrated by their co-occurrence in deposits assigned to the “'' Elephas mnaidriensis''” faunal complex, but apparently became extinct sometime before the end of the Pleistocene, prior the deposition of deposits assigned to the “Grotta S. Teodoro Pianetti” faunal complex.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 † Pleistocene rodents Pleistocene mammals of Europe Fossil taxa described in 1896 Prehistoric rodent genera Fossils of Malta Taxa named by Richard Lydekker

Discovery and taxonomy

Description

Ecology

Evolutionary history

See also

References