Leithia is an extinct genus of giant dormice from the Pleistocene of 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.
| Leithia Temporal range:
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|---|---|
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| Skeleton of Lethia melitensis | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Gliridae |
| Subfamily: | Leithiinae |
| Genus: | †Leithia Lydekker, 1896[1] |
| Type species | |
| †Myoxus melitensis | |
| species | |
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Discovery and taxonomy
editThe 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] Two species of Leithia, namely Leithia melitensis and the smaller L. cartei, lived in Sicily and Malta.[4]
Description
edit
The skull of Leithia melitensis reached a length of approximately 7 centimetres (2.8 in), roughly twice the length of that of the garden dormouse (Eliomys quercinus).[5] L. melitensis reached a total size comparable to a cat[6] or a rabbit,[7] with an estimated body mass of approximately 1 kilogram (2.2 lb).[8] 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.[5] The mandible of L. melitensis is also extremely robust.[9]
Ecology
editThe teeth of Leithia melitensis exhibit a variable amount of wear, indicating an abrasive, and probably largely herbivorous diet,[9] with the lower jaw exhibiting greater adaption to chewing rather than gnawing.[10] Leithia was likely predated upon by large birds of prey native to the islands, such as the endemic large barn-owl Tyto mourerchauvireae.[5]
Evolutionary history
editThe closest living relative of Leithia is assumed to be Eliomys, based on morphological similarities.[5] Remains tentively referred to Leithia are known from the Early Pleistocene (late Villafranchian) "Monte Pellegrino" faunal complex.[11][12] However, other authors have suggested that this taxon is instead more closely related to the genus Maltamys, also endemic to Sicily and Malta.[13] It has been suggested by some that the ancestors Leithia arrived in Sicily during the Late Miocene (Messinian) or Pliocene, but this is not preserved in the fossil record.[11][12] For most of the Middle Pleistocene 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, 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.[11][12]
See also
edit- List of extinct animals of Europe
- Hypnomys a genus of giant dormice known from the Balearic Islands
References
edit- ^ 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.
- ^ a b Adams, A. L. (1863), ‘Observations on the Fossiliferous caves of Malta’. Journal of the Royal Society, 4 .2. pp.11–19.
- ^ Wilson, Don E.; Reeder, DeeAnn M., eds. (2005). Mammal Species of the World: A Taxonomic and Geographic Reference, Volume 12. JHU Press. p. 829.
- ^ Petronio, C. (1970). "I Roditori Pleistocenici della Grotta di Spinagallo (Siracusa)" (PDF). Geol. Rom. IX: 149–194. Archived from the original (PDF) on 2016-03-04. Retrieved 2014-06-29. (in Italian)
- ^ a b c d 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. S2CID 221868671.
- ^ "Giant dormice the size of cats used to live on Sicily". www.nhm.ac.uk. Retrieved 2023-02-17.
- ^ Guglielmo, M.; Marra, A.C. Le due Sicilie del Pleistocene Medio: osservazioni paleogeografiche. [in Italian]. Biogeographia 2011, 30, 11–25.
- ^ van den Hoek Ostende, Lars W.; van der Geer, Alexandra A.E.; Wijngaarden, Carlijne L. (July 2017). "Why are there no giants at the dwarves feet? Insular micromammals in the eastern Mediterranean". Quaternary International. 445: 269–278. Bibcode:2017QuInt.445..269V. doi:10.1016/j.quaint.2016.05.007.
- ^ a b Hennekam, Jesse J.; Benson, Roger B. J.; Herridge, Victoria L.; Jeffery, Nathan; Torres-Roig, Enric; Alcover, Josep Antoni; Cox, Philip G. (2020-11-11). "Morphological divergence in giant fossil dormice". Proceedings of the Royal Society B: Biological Sciences. 287 (1938): 20202085. doi:10.1098/rspb.2020.2085. ISSN 0962-8452. PMC 7735280. PMID 33143584.
- ^ Hennekam, Jesse J; Herridge, Victoria L; Cox, Philip G (2023-06-01). "Feeding biomechanics reveals niche differentiation related to insular gigantism". Evolution. 77 (6): 1303–1314. doi:10.1093/evolut/qpad041. ISSN 0014-3820. PMID 36881990.
- ^ a b c Bonfiglio, Laura; Mangano, Gabriella; Marra, Antonella Cinzia; Masini, Federico; Pavia, Marco; Petruso, Daria (December 2002). "Pleistocene Calabrian and Sicilian bioprovinces". Geobios. 35: 29–39. Bibcode:2002Geobi..35...29B. doi:10.1016/S0016-6995(02)00046-3. hdl:2318/89144.
- ^ a b c 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.
- ^ 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.