5.
Painted Spiny Pocket Mouse
Heteromys pictus
French: Souris-a-ajaboues peinte / German: Bunte Stacheltaschenmaus / Spanish: Raton espinoso pintado
Taxonomy. Heteromys pictus Thomas, 1893,
San Sebastian, 4,300 ft., Jalisco, Mexico.
In 2007, J. C. Hafner and colleagues confirmed paraphyly of Liomys relative to Heteomys, so they placed Liomys in synonymy with Heteromys. This species (formerly Liomys pictus) forms a distinct clade within the genus along with H. irroratus and H. spectabilis. Both mtDNA sequence data and allozymes indicate that H. pictus is paraphyletic relative to H. spectabilis. Heteromys spectabilis is more similar to H. p. hispidus than that subspecies is to the remaining subspecies of H. pictus, although the two species are clearly differentiated (based on allozymes, karyotype, and sequence data) where they occur in sympatry in Jalisco. Four subspecies recognized.
Subspecies and Distribution.
H. p. pictus Thomas, 1893 — W, SW, S & SE Mexico (coast of S Nayarit to Chiapas, S Veracruz) and W Guatemala.
H. p. annectens Merriam, 1902 — S Mexico (Sierra Madre del Sur of Guerrero and Oaxaca).
H. p. hispidus J. A. Allen, 1897 — NW and W Mexico (N Sonora to Nayarit and CJalisco).
H. p. plantinarensis Merriam, 1902 — SC Mexico (interior basins and valleys of SE Jalisco, E Colima, C Michoacan, and N Guerrero).
Descriptive notes. Head—body mean 110 mm, tail 91-168 mm, hindfoot 22-35 mm; weight 30-80 g. Male Painted Spiny Pocket Mice are, on average, slightly larger than females. It is scansorial and small-sized for the genus, with coarse adult pelage having abundantstiff, flattened spine-like hairs on dorsal and lateral surfaces of body. Upper parts are reddish brown, there is usually an ocherous lateral line, and belly is white. Hairs on back are not curled upward so as to be conspicuous above spines. Posterior parts of soles of hindfeet are sparsely haired, usually with six plantar tubercles (five in some individuals of plantinarensis); claw of second digit on hindfoot is spoon-like, apparently an adaptation for digging. Tail is moderately haired and darker on upper part. Cheekteeth have medium-high crowns, and lower premolar has two lophids. Auditory bullae are only moderately inflated. Chromosomal complement has 2n = 48 and FN = 66. In areas of potential sympatry, the Painted Spiny Pocket Mouse is smaller than the other two species. Where it occurs with Salvin’s Spiny Pocket Mouse (H. salvini) in coastal Oaxaca and Chiapas, the Painted Spiny Pocket Mouse is distinguished by its much larger overall size, color (reddish brown vs. chocolate brown or paler), and lateralstripe. Hairs on back also are not curled upward and visible above spines as they are in Salvin’s Spiny Pocket Mouse.
Habitat. Arid lowlands of the Sonoran Desert to arid lowland tropics along the west and east coasts of Mexico, to cloud forests of Guerrero and Oaxaca, from sea level to elevations of ¢.2400 m. The Painted Spiny Pocket Mouse occurs most often in lowland dry forest but prefers moist habitats along rivers and streams in otherwise arid inland situations. Whereit is sympatric with the Mexican Spiny Pocket Mouse (H. irroratus), in a band from central Jalisco to mountains of Sierra Madre del Sur in Oaxaca, it occupies low, more mesic areas, whereas the Mexican Spiny Pocket Mouse occupies dry upland areas. In the cloud forest of La Cima, Oaxaca, the two species were collected in the same habitat. Along the west coast, the Painted Spiny Pocket Mouse is more abundant in moist situations along rivers and streams than in dry thorn forest. Burrow entrances are often covered with leaves or a small mound of soil.
Food and Feeding. Diet of the Painted Spiny Pocket Mouse consists mostly of seeds but also green plants and insects,all of which are transported in its external, fur-lined cheek pouches back to its burrow for storage. Seeds of acacia (Acacia, Fabaceae), fig (Ficus, Moraceae), bindweed (Convolvulus, Convolvulaceae), and mesquite (Prosopis, Fabaceae) are eaten. Relative proportion of vegetable and animal foods in the diet varies widely, suggesting opportunistic feeding.
Breeding. The Painted Spiny Pocket Mouse probably breeds throughout the year, except early in the dry season. Averagelittersize is 3-9 young.
Activity patterns. The Painted Spiny Pocket Mouse is nocturnal and active throughout the year.
Movements, Home range and Social organization. The Painted Spiny Pocket Mouse is solitary, and mating system is probably promiscuous or effectively polygynous: mate pairings usually do not last through parturition. Painted Spiny Pocket Mice segregate by sex into different parts of their habitat. Densities fluctuates extensively, estimated at 5-30 ind/ha.
Status and Conservation. Classified as Least Concern on The IUCN Red List (as Liomys pictus).
Bibliography. Best (1993a), Ceballos & Oliva (2005), Genoways (1973), Hafner et al. (2007), Jones (1993), McGhee & Genoways (1978), Rogers & Vance (2005), Sanchez-Cordero & Fleming (1993), Vazquez, Emmons, Reid & Cuarén (2008b), Williams et al. (1993).