''Rhagamys'' is an

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 ...

genus of rodents in the subfamily Murinae, the Old World mice and rats. The genus was established by the Swiss zoologist

Charles Immanuel Forsyth Major Charles Immanuel Forsyth Major (15 August 1843, Glasgow – 25 March 1923, Munich) was a Scottish-born, Swiss physician, zoologist and vertebrate palaeontologist. Major was born in Glasgow and studied at Basel and Zurich Universities in Switzerl ...

to accommodate ''Rhagamys orthodon'', commonly known as Hensel's field mouse or the Tyrrhenian field rat, which is the only species in the genus. It was endemic to the Mediterranean islands of

Corsica Corsica ( , Upper , Southern ; it, Corsica; ; french: Corse ; lij, Còrsega; sc, Còssiga) is an island in the Mediterranean Sea and one of the 18 regions of France. It is the fourth-largest island in the Mediterranean and lies southeast of ...

and Sardinia, where it first appeared in the fossil record in the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division of ...

, and was relatively large in size, weighing up to 50 g. Its closest living relatives are of the genus '' Apodemus''.

Taxonomy and evolution

The ancestors of ''Rhagamys'', belonging the widespread genus '' Rhagapodemus'', first arrived in Corsica-Sardinia during the

Early Early may refer to: History * The beginning or oldest part of a defined historical period, as opposed to middle or late periods, e.g.: ** Early Christianity ** Early modern Europe Places in the United States * Early, Iowa * Early, Texas * Early ...

- Late Pliocene transition, around 3.6 million years ago. Three chronospecies of the lineage have been named, including "''Rhagapodemus''" ''azzarolii'' from the earliest Late Pliocene, followed by "''Rhagapodemus''" ''minor'' from the Early Pleistocene, succeeded by ''Rhagamys orthodon'', which ranged from the Middle Pleistocene to Holocene. The molars of ''Rhagamys'' are similar to those of the wood mouse (''Apodemus sylvaticus'') and the

striped field mouse The striped field mouse (''Apodemus agrarius'') is a rodent in the family Muridae. The range of this species stretches from Eastern Europe to Eastern Asia. Synonyms Accepted synonyms include ''Apodemus albostriatus'' (Bechstein, 1801), ''Apode ...

(''Apodemus agrarius'') but are larger and more derived, being hypsodont teeth suitable for feeding on a coarse, abrasive diet. Over time, ''Rhagamys orthodon'' increased in size and became larger than the

broad-toothed field mouse The eastern broad-toothed field mouse (''Apodemus mystacinus'') is a species of rodent in the family Muridae. Distribution Following the classification of the Balkan population as a separate species western broad-toothed field mouse The wes ...

(''Apodemus mystacinus'').

History

Before the arrival of humans on the islands in about 8000 BC, Corsica and Sardinia had their own highly endemic depauperate terrestrial mammal fauna which besides ''Rhagamys orthodon'' included a species of dwarf mammoth ('' Mammuthus lamarmorai''), the Tyrrhenian vole (''

Microtus henseli ''Microtus henseli'', the Tyrrhenian vole or Hensel's vole, was a rodent found in Sardinia and Corsica Corsica ( , Upper , Southern ; it, Corsica; ; french: Corse ; lij, Còrsega; sc, Còssiga) is an island in the Mediterranean Sea and on ...

''), the Sardinian pika (''

Prolagus sardus The Sardinian pika (''Prolagus sardus'') is an extinct species of pika that was endemic to the islands of Sardinia, Corsica and neighbouring Mediterranean islands until its extinction likely in Ancient Rome, Roman times. Unlike living pikas, whic ...

''), one or two species of shrew belonging to the genus '' Asoriculus'', a mole (''

Talpa tyrrhenica The Tyrrhenian mole (''Talpa tyrrhenica'') is an extinct species of mammal in the family Talpidae. It was endemic to the Mediterranean islands of Corsica and Sardinia during the Pleistocene epoch. First described in 1945 by Dorothea Bate, this s ...

''), the

Sardinian dhole The Sardinian dhole (''Cynotherium sardous'') is an extinct insular canid which was endemic to what is now the Mediterranean islands of Sardinia (Italy) and Corsica (France), which were joined for much of the Pleistocene. It went extinct when h ...

(''Cynotherium sardous''), a galictine mustelid ('' Enhydrictis galictoides''), three species of

otter Otters are carnivorous mammals in the subfamily Lutrinae. The 13 extant otter species are all semiaquatic, aquatic, or marine, with diets based on fish and invertebrates. Lutrinae is a branch of the Mustelidae family, which also includes wea ...

(''

Algarolutra majori ''Algarolutra'' is an extinct endemic genus of otter from the Pleistocene of Corsica and Sardinia. The single species ''A. majori'' was originally attributed to the genus ''Cyrnaonyx'' and its type species In zoological nomenclature, a type spe ...

, Sardolutra ichnusae,

Megalenhydris barbaricina ''Megalenhydris barbaricina'' is a Late Pleistocene giant otter from Sardinia. It is known from a single skeleton, discovered in the ''Grotta di Ispinigoli'' near Dorgali, and was described in 1987. The species is one of four extinct otter specie ...

'') and a deer (''

Praemegaceros cazioti ''Praemegaceros'' is an extinct genus of deer, known from the Pleistocene and Holocene of Western Eurasia. It contains the subgenera ''Praemegaceros,'' ''Orthogonoceros'' and ''Nesoleipoceros''. It has sometimes been synonymised with ''Megaloce ...

''). The small mammals, including ''Rhagamys'', persisted for many thousands of years after the first human arrival on the islands, with the youngest radiocarbon dates for ''Rhagamys'' dating to around 800 BC. It was almost certainly extinct by the 6th century AD. The cause of the extinction is unknown, but may be due to invasive species introduced by new arrivals to the islands such as Carthaginians and the Romans. The only endemic mammal still found on the islands is the Sardinian long-eared bat (''Plecotus sardus'').

References

{{Taxonbar, from=Q10811507 Old World rats and mice Mammals of Europe Pleistocene rodents Rodent genera Taxa named by Charles Immanuel Forsyth Major Extinct rodents Mammals described in 1856 Fossil taxa described in 1856