| Rhagamys | |
|---|---|
 | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Rodentia |
| Family: | Muridae |
| Tribe: | Apodemini |
| Genus: | †Rhagamys Major, 1905 |
| Species: | †R. orthodon |
| Binomial name | |
| †Rhagamys orthodon Hensel, 1856 | |
Rhagamys is anextinctgenus ofrodents in the subfamilyMurinae, the Old World mice and rats. The genus was established by the Swiss zoologistCharles Immanuel Forsyth Major to accommodateRhagamys orthodon, which is the only species in the genus. It wasendemic to the Mediterranean islands ofCorsica andSardinia, descending fromRhagapodemus, which had colonised the islands around 3.6 million years ago. Its closest living relatives are of the genusApodemus, which includes the field and wood mice.
The ancestors ofRhagamys, belonging the widespread genusRhagapodemus, first arrived in Corsica-Sardinia during theEarly-Late Pliocene transition, around 3.6 million years ago. Threechronospecies of the lineage have been named, including "Rhagapodemus"azzarolii from the earliest Late Pliocene, followed by "Rhagapodemus"minor from the Early Pleistocene, succeeded byRhagamys orthodon, which ranged from the Middle Pleistocene to Holocene.[1] Themolars ofRhagamys are similar to those of thewood mouse (Apodemus sylvaticus) and thestriped field mouse (Apodemus agrarius) but are larger and more derived, beinghypsodont teeth suitable for feeding on a coarse, abrasive diet.[2] Over time, TheRhagapodemus-Rhagamys lineage increased in size,[3] withRhagamys orthodon having an estimated mass of approximately 90 grams (3.2 oz),[4] two and a half times larger than its mainland ancestor, an example ofisland gigantism.[5]
Before the arrival of humans on the islands in about 8000 BC, Corsica and Sardinia had their own highlyendemic depauperate terrestrial mammal fauna which besidesRhagamys orthodon included a species of dwarfmammoth (Mammuthus lamarmorai), the Tyrrhenian vole (Microtus henseli), the Sardinian pika (Prolagus sardus), the shrewAsoriculus similis, amole (Talpa tyrrhenica), theSardinian dhole (Cynotherium sardous), agalictinemustelid (Enhydrictis galictoides), three species ofotter (Algarolutra majori,Sardolutra ichnusae,Megalenhydris barbaricina) and adeer (Praemegaceros cazioti).[6] The small mammals, includingRhagamys, persisted for many thousands of years after the first human arrival on the islands, with the youngest radiocarbon date forRhagamys on Sardinia being around 822-776 BC, while on Corsica the youngest dates for the species are around 393 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.[7]
The only endemic mammal still found on the islands is theSardinian long-eared bat (Plecotus sardus).[8][9]
