Dipodomys merriami Mearns 1890
Creators: name: Don E. Wilson
name: Thomas E. Lacher, Jr
name: Russell A. Mittermeier
Publisher: name: Lynx Edicions
Year: 2016
Subjects: Biodiversity
Taxonomy
Animalia
Chordata
Mammalia
Rodentia
Heteromyidae
Dipodomys
Dipodomys merriami

description: 54.
Merriam’s. 9 Kangaroo Rat
. Dipodomys merriami
. French: Rat-kangourou de Merriam / German: Merriam-Kangururatte / Spanish: Rata canguro de Merriam
Other common names: Margarita Island Kangaroo Rat (margaritae), San Bernardino Kangaroo Rat (parvus), San José Island Kangaroo Rat (insularis)
Taxonomy. Dipodomys merriami Mearns, 1890,
New River, between Phoenix and Prescott, Maricopa Co., Arizona, USA.
Based on molecular sequence analyses, D. merriami is a member of the merriami species group, along with D. nitratoides. This widespread species occurs in the Great Basin, Mojave, Peninsular, Sonoran, and Chihuahuan deserts and has three clearly differentiated clades, two of which are further divided into two subclades each: subspecies insularis, margaritae, and melanurus of the southern Baja California peninsula that is basal to all others, a Chihuahuan Desert clade that is divided into two subclades, north (ambiguus) and south (atronasus) of the Southern Coahuila filterbarrier, and a northern clade that includes one subclade in the central Baja California peninsula (annulus, brunensis, and platycephalus) and another subclade that includesall remaining subspecies. Nineteen subspecies recognized.
Subspecies and Distribution.
D. m. merriami Mearns, 1890 — SW USA and NW Mexico (desert regions from N Nevada and extreme SW Utah, through SE California and SW Arizona, to NE Baja California and Sonora).
D. m. ambiguus Merriam, 1890 — SW USA and NW Mexico (N portion of the Chihuahuan Desert from NC New Mexico and W Texas, through E Chihuahua and Coahuila, to NE Durango, N Zacatecas, and C Nuevo Leon).
D. m. annulus Huey, 1951 — NW Mexico (coastal plains of the Gulf of California, SE Baja California).
D. m. arenivagus Elliot, 1904 — SW USA and NW Mexico (S Mojave Desert of SC California and E of Sierra Juarez and Sierra San Pedro Martir to C Baja California).
D. m. atronasus Merriam, 1894 — NC Mexico (southern portion of the Chihuahuan Desert from EC Zacatecas, SE Coahuila, and SW Nuevo Leon to Aguascalientes and San Luis Potosi).
D. m. brunensis Huey, 1951 — NW Mexico (Gulf of California coast of NE Baja California Sur).
D. m. collinus Lidicker, 1960 — SW USA (San Felipe, Earthquake, La Puerta, and Aguanga valleys of SW California).
D. m. frenatus Bole, 1936 — SW USA (SW Utah and NW Arizona).
D. m. insularis Merriam, 1907 — NW Mexico (San José I, Gulf of California, Baja California Sur).
D. m. margaritae Merriam, 1907 — NW Mexico (Santa Margarita I, Baja California Sur).
D. m. mayensis Goldman, 1928 — NW Mexico (Gulf of California coastal plains of S Sonora and N Sinaloa).
D. m. melanurus Merriam, 1893 — NW Mexico (Magdalena Plains and Cape Region of S Baja California Sur).
D. m. mitchelli Mearns, 1897 — NW Mexico (Tiburon I, Gulf of California, Sonora).
D. m. olivaceus Swarth, 1929 — SW USA and NW Mexico (transitional zone between the Sonoran Desert of SE Arizona and NE Sonora, and the Chihuahuan Desert of SW New Mexico and NW Chihuahua).
D. m. parvus Rhoads, 1894 — SW USA (San Bernardino and San Jacinto valleys of SW California).
D. m. platycephalus Merriam, 1907 — NW Mexico (Pacific slope S of the Sierra San Pedro Martir, S Baja California to the Vizcaino Desert of N Baja California Sur).
D. m. quintinensis Huey, 1951 — NW Mexico (San Quintin Plain, Pacific coast of NW Baja California).
D. m. trinidadensis Huey, 1951 — SW USA and NW Mexico (S California and N Baja California).
D. m. vulcani Benson, 1934 — SW USA (disjunct and restricted distribution in Toroweap Valley, NW Arizona).
Descriptive notes. Head—-body 75-100 mm,tail 120-182 mm, ear mean 14 mm, hindfoot mean 38 mm; weight 32-53 g. Male Merriam’s Kangaroo Rats are slightly larger than females. Tail is ¢.145% of head-body length. This is a small-sized kangaroo rat with four toes on relatively slender hindfeet, narrow rostrum, and more inflated auditory bullae. Upper parts are buff; tail is bicolored, with dull brownish-black crest and tuft. Chromosomal complement has 2n = 52 and FN = 100. Merriam’s Kangaroo Rat and the San Joaquin Kangaroo Rat (D. nitratoides) occupy the Mojave and San Joaquin Valley deserts, respectively, on either side of the Tehachapi Mountains and are closely related and similar in appearance; Merriam’s Kangaroo Rat is generally larger, with longer and wider rostrum.
Habitat. Wide variety of soil types and arid vegetation communities throughout the Great Basin, Mojave, Peninsular, Sonoran, and Chihuahuan deserts. Distribution of Merriam’s Kangaroo Rat matches that of creosote bush (Larrea tridentata, Zygophyllaceae), extending outside of it into the low-elevation, western edge of the Great Basin, the Cape Region of the Baja California peninsula, and thornscrub of the Sonoran plains into northern Sinaloa, Mexico. Where it occurs with other kangaroo rats, Merriam’s Kangaroo Rat will usually be found in harder, rockier soils. The only island populations of kangaroo rats are of Merriam’s Kangaroo Rats off of Baja California Sur’s Pacific coast (margaritae) and Gulf of California coast (insularis) and on Tiburén Island of Sonora (mitchell).
Food and Feeding. Seeds obtained within c.10 m of the burrow of a Merriam’s Kangaroo Rat were cached in larders, while more distant seeds were stored in scattered surface caches. Diet includes seeds of forbs, grasses, and shrubs and generally reflects whatis available in the seed soil bank; some green vegetation and insects are also eaten. Although Merriam’s Kangaroo Rat is among the most arid-adapted of the genus, green vegetation can compose 40% of its diet in spring. Burrow systems of Merriam’s Kangaroo Rat tend to be less complex than those of other kangaroo rats, and openings are usually around bases of shrubs.
Breeding. Breeding season of Merriam’s Kangaroo Rat begins in February and extends at least through May. Averagelittersizes are 2-3 young (range 2-4).
Activity patterns. Nocturnal foraging activity of Merriam’s Kangaroo Rat is usually limited to less than two hours within a 2-6-hour period, often with peaks of activity just after dusk and just before dawn. Most foraging is on the ground, but Merriam’s Kangaroo Rat will climb to harvest seed heads and insect galls associated with stems of creosote bushes.
Movements, Home range and Social organization. Merriam’s Kangaroo Rat is more tolerant of conspecifics away from their own core area than of immediate neighbors. Olfactory communication is likely most important, through direct contact or at sites of sand bathing. There is evidence that Merriam’s Kangaroo Rat can discriminate among species, and individuals are attracted to sand-bathing sites of conspecifics, although reproductive condition of females does not appear to be communicated through sand bathing. Dispersal of Merriam’s Kangaroo Rat does not show malebiased pattern typical of mammals. Instead, c¢.84% of young kangaroo rats dispersed less than 100 m from natal home ranges with little difference between sexes, and most juveniles took up residence in unoccupied areas, most often within the home range of adult females.
Status and Conservation. Classified as Least Concern on The IUCN Red List. Subspecies insularis and margaritae (both treated as full species of Dipodomys) are classified as Critically Endangered. The US Fish and Wildlife Servicelists the San Bernardino Kangaroo Rat (parvus) in California’s coastal chaparral as endangered due to urban development. Although the population on San José Island (insularis) was thought to be extinct due to predation by feral cats (Felis catus), five extant populations were discovered in 2005. This subspecies and the subspecies on Santa Margarita Island (margaritae) are considered threatened by feral cats and feral dogs, although Merriam’s Kangaroo Rat was rarely found in feces offeral cats on San José Island.
Bibliography. Alexander (2001), Alexander & Riddle (2005), Alvarez-Castafieda, Castro-Arellano, Lacher, Vazquez & Arroyo-Cabrales (2008a, 2008b), Alvarez-Castaneda, Lidicker & Rios (2009), Best (1992a, 1993a), Best & Thomas (1991a), Ceballos & Oliva (2005), Daly et al. (1992), Eisenberg (1963, 1993), Espinosa-Gayosso & Alvarez-Castaneda (2006), Hafner et al. (2007), Hall (1981), Ingles (1954), Jones (1993), Lancaster (2000), Linzey, Timm, Alvarez-Castafieda, Castro-Arellano & Lacher (2008b), Patton & Rogers (1993), Riddle, Hafner, Alexander & Jaeger (2000), Rogers (1999), Williams et al. (1993).
description: Published as part of Don E. Wilson, Thomas E. Lacher, Jr & Russell A. Mittermeier, 2016, Heteromyidae, pp. 170-233 in Handbook of the Mammals of the World – Volume 6 Lagomorphs and Rodents I, Barcelona :Lynx Edicions on pages 226-227, DOI: 10.5281/zenodo.6611160