Oryzomys nelsoni

Skull of Nelson rice rat, from above

The Nelson rice rat ( Oryzomys nelsoni ) is an extinct rodent of the genus rice rats ( Oryzomys ). She was on the Marias Islands belonging María Madre Island endemic off the west coast of Mexico and is only four known adult animals that were collected there in May 1897 by Edward William Nelson and Edward Alphonso Goldman.

Features

The Nelson rice rat was one of the large species of the genus Oryzomys and had a tail, whose length was significantly larger than the head-body length. The total length of the four known specimens of 320-344 mm, tail length 185-191 mm, and the Hinterfußlänge 37 to 39 mm. The top was intense yellowish -brown, the staining was particularly strong on the lower back and went to the head, shoulders and lower edges in a lighter, warm beige brown over. Head and back were by blackish hair slightly darker. The underside was white, occasionally lead-colored translucent undercoat. The outer and inner sides of the ears were loosely covered with gray hairs. The tail underside was bright yellow grassroots level to one third or to one half, the remaining tail was dark.

Habitat and behavior

The Nelson rice rat occurred in about 550 m altitude in humid areas near sources and near the highest elevation of Maria Madre. The habitat is characterized by a lush herbaceous vegetation in the understory. The food is likely to have consisted of seeds, fruits, grasses, and occasionally from small fish and invertebrates.

Extinction

When conducted in 1991 intensive small mammal traps at the type locality only were able to house rats ( Rattus rattus ) could be detected. The Nelson rice rat is classified by the IUCN therefore since 1996 as " Extinct " ( " extinct "). Cause of the disappearance of the species is probably the displacement by the entrained house rat.