The San Bernardino kangaroo rat (Dipodomys merriami parvus ) is a species of rodent in the family Heteromyidae. It is one of 19 recognized subspecies of Merriam's kangaroo rat (Dipodomys merriami ) that are spread throughout the arid regions of the southwestern United States and Mexico.
Like Dipodomys merriami, the San Bernardino kangaroo rat has the diagnostic trait of having four toes on its hind legs. Additionally, because of its geographic isolation, it has become the most highly differentiated subspecies of D. merriami.
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starts withThe San Bernardino kangaroo rat follows the same body plan as Dipodomys merriami and other kangaroo rat species: large hind feet for jumping, long tail for balance while jumping, cheek pouches for foraging, and so on. Its body is about 95 millimeters (3.7 inches) long, with a total length of 230–235 mm (9.1–9.3 in). Its body color is weakly yellow with a heavy overwash of dusky brown. The tail stripes are medium to dark brown, with dark brown tail hairs and foot pads. Its flanks and cheeks are dusky.
D. m. parvus is substantially darker and smaller than the other two D. merriami subspecies that live in Southern California (Dipodomys merriami merriami and Dipodomys merriami collinus ). This marked adaptation to its habitat has led Lidicker to say that "it seems likely to have achieved nearly species rank." (Lidicker 1960)
In most heteromyids, soil texture is a primary factor in determining species distributions. (Brown and Harney, 1993) The range of D. m. parvus is isolated from members of D. m. merriami at the northernmost extent of their range by 8–13 kilometers (5.0–8.1 miles) of unsuitable habitat, indicating possible past intergradation of the two subspecies.
San Bernardino kangaroo rats inhabit places with sandy loam substrates, characteristic of alluvial fans and flood plains, where they are able to dig small, simple burrows. Plant life in such areas is typically dominated by chaparral and coastal sage scrub (soft chaparral). These alluvial scrub habitats can be classified as pioneer, intermediate, and mature, in order of decreased frequency of flooding and increased density of plants. Of these subsections of this particular habitat, D. m. parvus is most populous in intermediate alluvial scrub.
Dipodomys merriami parvus is found unequally distributed between seven isolated locations. The four smallest remnant populations reside near City Creek, Etiwanda, Reche Canyon, and South Bloomington. The largest populations with the most area of suitable habitat are located near the Santa Ana River, Lytle and Cajon Creek, and the San Jacinto River.
The historical range of D. m. parvus encompassed roughly 320,000 acres (130,000 hectares). By the 1930s its range had been reduced to roughly 28,000 acres (11,000 hectares). In 1998, its range was approximated at only 3,247 acres (1,314 hectares).
