757.

Big-eared Climbing Rat

Ototylomys phyllotis

French: Tylomys a grandes oreilles / German: GroRohrKletterratte / Spanish: Rata trepadora de orejas grandes

Taxonomy. Ototylomys phyllotis Merriam, 1901, Tunkas, Yucatan, Mexico.

There are three distinct haplotypes that correspond to morphometric information. Genetic and morphometric evidence of populations in Costa Rica suggest a different form that should be subjected to taxonomic revision. Three subspecies recognized.

Subspecies and Distribution.

O.p.phyllotisMerriam,1901—EMexico(YucatanPeninsula),Belize,EGuatemala,Honduras,ElSalvador,andNicaragua.

O.p.australisOsgood,1931—NWCostaRica.

O. p. connectens Sanborn, 1935 — SE Mexico (S Tabasco and Chiapas) and C Guatemala (Coban, Chimoxan, Finca Chama, and Alta Verapaz).

There is a record of two skulls of a unknown subspecies in owl regurgitations in a cave in the center of Guerrero, Mexico, 700 km W from the current known distribution.

Descriptive notes. Head-body 124-164 mm, tail 109-174 mm; weight 80-120 g. The Big-eared Climbing Rat is medium-sized; patch of white at bases of ears is distinguishing. It has slim body and abundant soft fur. Back varies in shades of gray with cinnamon cream, and belly is white—variation occurs throughout its distribution. It has big eyes and big, naked, pale brown ears. Tail is long, naked, shiny, and covered with scales that form wide rings. It has four inguinal teats. Karyotype 1s 2n = 48, with 32 metacentric and submetacentric, and 14 acrocentric chromosomes. Sex chromosomes are long; X is metacentric and Y is submetacentric.

Habitat. Tropical rainforest, deciduous dry forests, cloud forest, secondary vegetation, rocky areas, and coffee plantations up to elevations of ¢.2000 m.

Food and Feeding. The Big-eared Climbing Rat eats leaves,fruits, and seeds. South of the Yucatan,it eats tree bark during the dry season. It has been caught in traps baited with mixture of oats and vanilla.

Breeding. The Big-eared Climbing Rat breeds year-round, with low level of reproductive activity during the dry season. Gestation lasts 30-40 days. Litters are small (usually two young/ litter). Postpartum estrus occurs after 24 hours. Females can be pregnant at 29 days of age. Burrows are at ground level, with openings among rocks, roots, and fallen trees. The Big-eared Climbing Rat can be separated into five age classes based on appearance and wear of teeth, cranial sutures, soft hair, and cranial and somatic metrics.

Activity patterns. The Big-eared Climbing Rat is semi-arboreal and nocturnal. South of the Yucatan, most activity occurs between 23:00 h and 01:00 h near the ground level.

Movements, Home range and Social organization. The Big-eared Climbing Ratis sociable and has been caught at ground level and in the canopy at heights of 0-5-3 m. When sympatric with Sumichrast’s Vesper Rat ( Nyctomys sumichrasti), it forages below 3 m. In the Yucatan, densities are 4-64 ind/ha, highest in the rainy season and in forests with abundant trees and shrubs that produce fruit and seeds throughout the year. Areas of activity of males are significantly larger than those of females; one male can move up to 600 m, varying with availability of food and sex ratio in a population.

Status and Conservation. Classified as Least Concern on The IUCN Red List. The Bigeared Climbing Rat has stable populations and wide distribution; it is tolerant of habitat modification and occurs in protected areas.

Bibliography. Alcérraca et al. (2009), Alvarez-Castaneda et al. (2015), Arita (2006), Cimé (2006), Gutierrez (2015), Gutiérrez-Garcia (2008), Gutiérrez-Garcia & Vazquez-Dominguez (2012), Gutiérrez-Garcia et al. (2014), Hernandez-Betancourt et al. (2008), Itz4-Ortiz et al. (2011), Lawlor (1969, 1982a), Saenz (1999), Ramirez-Pulido & Séanchez-Hernandez (1972), Ramirez-Pulido, Gonzalez-Ruiz et al. (2014), Reid (2009), Vazquez (2016), Wilson & Cole (2000).