The Chiapan climbing rat (Tylomys bullaris) is a species of rodent in the family Cricetidae. It is endemic to Mexico, known only from a single location near Tuxtla Gutiérrez in the state of Chiapas, from which its common name derives.
Taxonomy and description. The species was first described by the American zoologist Clinton Hart Merriam in 1901. It belongs to the genus Tylomys, which comprises the climbing rats of the subfamily Tylomyinae. The head-body length is approximately 166 mm (6.5 in), with a long tail typical of climbing rats.
Habitat and ecology. The species inhabits tropical deciduous forests. It is nocturnal and likely semi-arboreal (partially tree-dwelling), as suggested by its common name and its membership in the climbing rat group.
Conservation status. The Chiapan climbing rat is listed as Critically Endangered (Possibly Extinct) on the IUCN Red List of Threatened Species. The species is known from fewer than ten historical specimens, with the last individual collected in 1970—over 50 years ago. Its only known locality has experienced severe habitat loss due to the conversion of native forest to agricultural and urban uses. These factors have likely caused a critical decline in population numbers, and the species may already be extinct.
