741.

Darwin’s Leaf-eared Mouse

Phyllotis darwinii

French: Phyllotis de Darwin / German: Darwin-Blattohrmaus / Spanish: Raton orejudo de Darwin

Other common names: Darwin's Pericote

Taxonomy. Mus (Phyllotis) darwinii Waterhouse, 1837, “ Coquimbo,” Coquimbo, Chile .

Phyllotis darwinis the type species of the genus. One of the better studied rodents relative to its demography, ecology, and physiology, but its alpha-taxonomy is still poorly explored. Although traditionally viewed as a highly polytypic because of its large distribution, after seminal laboratory work by L. I. Walker and collaborators in the 1980s, P. darwinu was restricted to central Chile and progressively distinguished from P. xanthopygus . Three subspecies recognized.

Subspecies and Distribution.

P.d.darwiniiWaterhouse,1837—N&CWChile.

P.d.boedeckeriPhilippi,1900—CWChile(MauleRegion).

P. d. fulvescens Osgood, 1943 — CW Chile (Bio Bio Region).

Descriptive notes. Head-body 107-140 mm, tail 105-145 mm, ear 21-32 mm, hindfoot 21-31 mm; weight 53 g (males) and 42 g (males). Strong sexual dimorphism in body mass and growth rates were observed. Growth rates of males were faster than those of females, with males reaching larger adult body mass than females. Darwin’s Leaf-eared Mouse reaches largest mean body mass in winter and smallest in summer. Darwin’s Leaf-eared Mouse has relatively short dark fur, with very large ears and occasional buffy pectoral streak; underparts vary from white to creamy or pale buffy; ears are blackish; tail is sharply bicolored; and feet are white. Compared with parapatric Yellow-rumped Leaf-eared Mouse ( P. xanthopygus), Darwin’s Leaf-eared Mouse is slightly smaller and darker and browner dorsally, with paler lateral line; fur is shorter; and ears more naked. Chromosomal complement is 2n = 38, FN = 72.

Habitat. Typically but not exclusively Chilean matorral, semiarid thornscrub, sparse desert habitats, high-Andean ranges, and Araucaria (Araucariaceae) forests.

Food and Feeding. Darwin’s Leaf-eared Mouse is mainly granivorous and folivorous, but its diet varies geographically and can include fungi and insects.

Breeding. Darwin’s Leaf-eared Mouse is polygynous, with males competing for mates and territories during breeding and females selecting larger males. In the laboratory, strong aggressive interactions between males during mating period were observed, resulting in injuries and sometimes death. Breeding is very seasonal, starting in September (spring) and lasting until January or February (summer). Mean litter sizes were 4-2-5-2 young; females produce 2-3 litters/breeding season. Sexual differences in body size and age-specific growth suggest that sexes differ in some important life history features. Females attain their maximum weight at 100 days old, and males reach their maximum body mass beyond 200 days old, suggesting that females attain sexual maturity at younger ages than males.

Activity patterns. Darwin’s Leaf-eared Mouseis terrestrial and nocturnal.

Movements, Home range and Social organization. Mean home range length varied from 36-3 m to 76-9 m. Large numerical fluctuations and temporal variation in demographic variables have been found, with densities of less than 10 ind/ha to 230 ind/ha during El Nino events. Large term studies in semiarid north-central Chile show that Darwin’s Leafeared Mouse experiences dramatic fluctuations during and following rainfall pulses.

Status and Conservation. Classified as Least Concern on The IUCN Red List (as P. darwin).

Bibliography. Bozinovic, Rosenmann & Veloso (1988), Crespin & Lima (2006), D'Elia (2016d), Fulk (1975), Glanz & Meserve (1981), Greer (1965), Heffner et al. (2001), Hershkovitz (1962), Lima & Jaksic (1998a, 1998b, 1999b), Lima, Bozinovic & Jaksic (1997), Lima, Julliard et al. (2001), Lima, Keymer et al. (1999), Lima, Stenseth & Jaksic (2002), Lima, Stenseth, Leirs & Jaksic (2003), Luna et al. (2016), Mann (1978), Meserve (1981a), Meserve & Le Boulengé (1987), Meserve et al. (2011), Munoz-Pedreros et al. (1990), Nespolo, Bacigalupe & Bozinovic (2003), Nespolo, Bustamante et al. (2005), Osgood (1943a), Pearson (1958), Rezende & Bozinovic (2001), Sabat & Bozinovic (2000), Spotorno & Walker (1983), Steppan & Ramirez (2015), Tirado et al. (2008), Vasquez (1994), Walker, Rojas et al. (1999), Walker, Spotorno & Arrau (1984), Walker, Spotorno & Sans (1991), Waterhouse (1837, 1839).