EUGENE M. MCCARTHY, PHD GENETICS
Harris’ Ground Squirrel|
Ammospermophilus harrisii [Harris’ Ground Squirrel]
× Ammospermophilus leucurus [White-tailed Antelope Squirrel] ENHR(southwestern U.S.). Hafner (1981) demonstrated that A. leucurus is more similar in morphology A. harrisii where it comes into contact with A. harrisii on the lower Colorado River than are populations in northern Baja California treated as subspecies of A. leucurus, which suggests extensive hybridization between harrisii and leucurus. Riddle et al. 2000 (p. 169).
Note: Two populations (gordoni, michianus), treated as races of Pallas’s Squirrel (Callosciurus erythraeus), hybridize in the Salween drainage (Myanmar). Compared with gordoni, michianus is much paler, especially laterally, and its tail is yellow-tipped, not rusty. Hybrids between michianus and another population treated as a race (haemobaphes) occur in Yunnanfu (southern China). Also, two probable hybrids between two other such populations (ningpoensis, styani) were reported from Tunglu, Chekiang. Allen 1925b (pp. 10, 11).
Callosciurus erythraeus [Pallas’s Squirrel]
× Callosciurus finlaysonii [Finlayson’s Squirrel] NHR. These squirrels are in approximate parapatric contact in southeast Asia. Corbet and Hill (1992) note that specimens in the Zoological Reference Collection, Singapore, from “Ban Nong Bua (SW Laos)” include both C. finlaysonii and C. erythraeus, as well as “intermediates” (probable hybrids) from nearby sites. A specimen (USNM 254753) in the National Museum of Natural History was collected by H. M. Smith on March 3, 1929. Smith’s field catalogue in the USNM Division of Birds library gives the locale of collection as “Ban Na Luang, French Laos,” 18°00’N, 104°13’E. Moore and Tate (1965, p. 174) considered it a probable hybrid derived from this cross. Thomas (1892, p. 24) decribes a probable hybrid from Bhamo in northern Burma as having flanks and posterior back that were a “dull yellowish grizzled grey.”
Note: Since all types of prairie dogs are now rare, there is less contact, and presumably less hybridization between distinct prairie dog types than formerly when they were abundant.
Cynomys gunnisoni [Gunnison Prairie-Dog]
× Cynomys leucurus [White-tailed Prairie-Dog] ONHR(western Colorado). Contact zone is in the upper Gunnison River drainage (southwestern Gunnison Co.). Johnson 1968; Lechleitner 1969.
× Cynomys ludovicianus [Black-tailed Prairie-Dog] Parapatric contact zone (w U.S.). Contact occurs in New Mexico and southeastern Colorado. No hybrids as yet reported. Hoogland 2006 (p. 10).
Cynomys leucurus [White-tailed Prairie-Dog]
See also: Cynomys gunnisoni.
× Cynomys ludovicianus [Black-tailed Prairie-Dog] Parapatric contact zone (western U.S.). Contact occurs in Wyoming, northeastern Colorado, and southern Montana. No hybrids as yet reported. Hoogland 2006 (p. 10).
Cynomys ludovicianus [Black-tailed Prairie-Dog] See: Cynomys gunnisoni; C. leucurus.
Eutomias dorsalis [Cliff Chipmunk] Two populations (dorsalis, grinnelli), treated as races of this chipmunk, have a hybrid zone in northwestern Arizona (western and southwestern Mogollon Plateau). Hoffmeister 1986 (p. 155 and Map 5.40).
Eutomias quadrivittatus [Colorado Chipmunk] Two populations (quadrivittatus, rufus), treated as races of this chipmunk, hybridize in northeastern Arizona. Hoffmeister 1986 (p. 153 and Map 5.39).
Funisciurus sponsus [Red Bush Squirrel] See: Paraxerus sponsus.
Glaucomys sabrinus [Northern Flying Squirrel]
× Glaucomys volans [Northern Flying Squirrel] ENHR. HPF. A hybrid zone exists in southeastern Canada (north of Lake Ontario). Hybrids have the southern squirrel's shorter body and the northern's gray-white belly fur. Garroway et al. 2010, 2011, 2014.
Glaucomys volans [Northern Flying Squirrel] See: Glaucomys sabrinus.
Marmota baibacina [Grey Marmot]
× Marmota bobak [Bobak Marmot] ENHR. There is a hybrid zone in northern Kazakhstan. Nikolskii et al. 1983.
× Marmota sibirica [Tarbagan Marmot] ONHR(Mongolia). Smirin et al. 1985.
Marmota bobak [Bobak Marmot] See: Marmota baibacina.
Marmota monax [Groundhog]
× Homo sapiens [Human] Please see the separate article A human-groundhog hybrid?.
Marmota sibirica [Tarbagan Marmot] See: Marmota baibacina.
Paraxerus bridgemani [Bridgeman’s Bush Squirrel] See: Paraxerus cepapi × P. palliatus.
Paraxerus cepapi [Smith’s Bush Squirrel]
× Paraxerus palliatus [Red Bush Squirrel] ENHR(southeastern Africa). HPF(vh). Kingdon (p. 400) says this is an “example of hybridization on a grand scale between what appear to be very distinct species.” The broad hybrid zone extends from southern Tanzania through Mozambique and Malawi to northeastern South Africa. Numerous taxa have been based on what Kingdon (p. 402) says are “animals that are almost certainly the result of ancient hybridization.” These include from the lower Limpopo: Paraxerus palliatus auriventris, P. bridgemani auriventris, and P. cepapi auriventris; from northeastern Zululand: P. palliatus tongensis, P. bridgemani tongensis, and P. sponsus tongensis; from southern Mozambique to southern Tanzania: P. palliatus bridgemani, P. sponsus bridgemani, and P. bridgemani; from southern Mozambique P. palliatus sponsus and P. sponsus sponsus. Kingdon 1974b (pp. 397-403).
Paraxerus lucifer [Black-and-red Bush Squirrel]
× Paraxerus palliatus [Red Bush Squirrel] NHR(northeastern Tanzania). CON: Usambara Mountains. Two probable hybrids were collected near Lushoto. P. vexillarius (Swynnerton’s Bush Squirrel) is based on these specimens and may therefore be hybrid. Kingdon 1974b (p. 396).
Paraxerus ochraceus [Funisciurus sponsus. Ochre Bush Squirrel] Two populations (eclectus, jacksoni), treated as races of this squirrel, hybridize in Mt. Kenya’s foothills. Kingdon 1974b (p. 406).
Paraxerus palliatus [Red Bush Squirrel] See: Paraxerus cepapi; P. lucifer.
Paraxerus sponsus [Red Bush Squirrel] Synonym: Funisciurus sponsus. See: Paraxerus cepapi × P. palliatus.
Paraxerus vexillarius [Swynnerton’s Squirrel] See: Paraxerus lucifer × P. palliatus.
Sciurus deppei [Deppe's Squirrel]
× Sciurus yucatanensis (♂) [Yucatan Squirrel] CHR. CON: Central America. Gaumer kept a female Deppe's squirrel with a male Yucatán squirrel, and they produced five young (born in February). Gaumer 1917; Leopold 1959 (p.375).
Sciurus granatensis [Red-tailed Squirrel]
× Sciurus richmondi [Richmond’s Squirrel] NHR(Costa Rica). A probable male hybrid was collected at Cataratas, San Carlos (AMNH 141922). Jones and Genoways 1971, 1975a; Nelson 1898 (p. 147); Nitikman (1985, p. 6).
Sciurus richmondi [Richmond’s Squirrel] See: Sciurus granatensis.
Sciurus variegatoides [Variegated Squirrel]
× Sciurus yucatanensis [Yucatan Squirrel] Best et al. (citing Musser 1968 and Ruiz-Piña 1994) state that hybridization (“intergradation”) may occur in northern Belize. Best et al. 1995.
Sciurus vulgaris [Eurasian Red Squirrel]
× Felis catus [Domestic Cat] See the separate article: "Domestic Cat × Red Squirrel.
Sciurus yucatanensis [Yucatan Squirrel] See: Sciurus deppei, S. variegatoides.
Spermophilus armatus [Uinta Ground Squirrel]
× Spermophilus beldingi [Belding’s Ground Squirrel] NHR(nw U.S). Parapatric contact zone in southeastern Idaho and northern Utah (Hoffmann 1981 Fig. 9). Hall (1943b) reported a probable hybrid from the contact zone. Its back color was like armatus, but its tail was reddish, like beldingi.
× Spermophilus elegans [Wyoming Ground Squirrel] NHR(w U.S). Hall (1943b) reported a probable hybrid from the contact zone.
Spermophilus beldingi [Belding’s Ground Squirrel] See: Spermophilus armatus. Hybridization occurs between two populations (creber, oregonus) treated as races of this squirrel (Hall 1946; Jenkins and Eshelman 1984). In California, hybridization also occurs between oregonus and a third such population, beldingi (Howell 1938; Jenkins and Eshelman 1984).
Spermophilus elegans [Wyoming Ground Squirrel]
See also: Spermophilus armatus.
× Spermophilus richardsonii [Richardson’s Ground Squirrel] ONHR(w U.S.). CON: lower Madison River valley (southwestern Montana). Here, populations having 2n = 34 are equated with S. elegans, and populations having 2n = 36 are equated with S. richardsonii. Koeppl et al. (1978) analyzed the acoustical behavior of hybrids and found that their chirps were variably intermediate between the two typical parental chirps, with some hybrids producing calls very similar to one parent or the other. Churr calls of hybrids, though, were more consistently different from either parental-type churr. Michener and Koeppl 1985; Nadler et al. 1971a; Stupca et al. 1978; Zegers 1984.
Spermophilus erythrogenys [Red-cheeked Ground Squirrel]
× Spermophilus major [Russet Ground Squirrel] ENHR. There is a hybrid zone in northern Kazakhstan (Kurgan Oblast, Tobol-Ishim Interfluve). HPF. Most genetically hybrid animals are not detectable on the basis of morphology. Hybrid calls combine traits of the two parents’ calls. Nikol’skii 1984; Nikol’skii and Starikov 1997; Spiridonova et al. 2005.
Spermophilus fulvus [Yellow Ground Squirrel]
× Spermophilus major (♂) [Russet Ground Squirrel] ENHR(sw Russia). HPF. CON: left bank of Volga, across from Suratov. Two to three percent of animals in the contact zone are hybrid. Ermakov et al. (2002) identified hybrids using RAPD-PCR of nuclear DNA. In addition, many squirrels that were phenotypically S. major had S. fulvus mtDNA. Bazhanov 1944; Ermakov 1997; Ognev 1963 (p. 13).
Spermophilus richardsonii [Richardson’s Ground Squirrel] See: Spermophilus elegans.
Spermophilus major [Russet Ground Squirrel]
See also: Spermophilus erythrogenys; S. fulvus.
× Spermophilus pygmaeus (♀) [Little Ground Squirrel] ENHR(w Russia). HPF. CON: southeastern Volga Basin, between Suratov and Ural’sk. About 1% of animals in the contact zone are hybrid. Ermakov et al. (2002) identified hybrids using RAPD-PCR of nuclear DNA. Also, many squirrels that were phenotypically S. major had S. pygmaeus mtDNA. Bazhanov 1944; Denizov 1963; Ermakov 1996; Formozov and Nikol’skii 1986.
× Spermophilus suslicus [Spotted Souslik] ONHR(southwestern Russia). CON: Volga basin (south of Cheboksary). Bazhanov 1944; Ermakov et al. 2002.
Spermophilus mexicanus [Mexican Ground Squirrel]
× Spermophilus tridecemlineatus [Thirteen-lined Ground Squirrel] CAENHR(southwestern U.S.). HPF(♂&♀). Hybrid zone is in western Texas and southeastern New Mexico. Cothran 1982, 1983; Cothran and Honeycutt 1984; Cothran et al. 1977; Nadler and Hughes 1966; Young and Jones 1982; Zimmerman and Cothran 1976.
Spermophilus mohavensis [Mojave Ground Squirrel]
× Spermophilus tereticaudus [Round-tailed Ground Squirrel] ENHR(sw U.S.). Hybridization occurs along a 240-km-long contact zone in the northwestern Mojave Desert in south-central California. Hafner 1992; Hafner and Yates 1983; Wessman 1977. Internet Citations: SPERM.
Spermophilus parvidens [Rio Grande Ground Squirrel]
× Spermophilus tridecemlineatus [Thirteen-lined Ground Squirrel] ENHR(southwestern U.S.). HPF(♂&♀). Hybrid zone is in western Texas and southeastern New Mexico. Thompsen et al. 2013.
Spermophilus pygmaeus [Little Ground Squirrel]
See also: Spermophilus major.
× Spermophilus suslicus [Spotted Souslik] ENHR(southwestern Russia). HPF. Hybrid zone is on right bank of Volga. Bazhanov 1944; Denizov 1961; Ermakov et al. 2002; Ipat’eva and Kozlova 1980.
Spermophilus suslicus [Spotted Souslik] See: Spermophilus pygmaeus.
Spermophilus tereticaudus [Round-tailed Ground Squirrel] See: Spermophilus mohavensis.
Spermophilus tridecemlineatus [Round-tailed Ground Squirrel] See: Spermophilus mexicanus; S. parvidens.
Tamias amoenus [Yellow-pine Chipmunk]
× Tamias ruficaudus (♀)[Red-tailed Chipmunk] ENHR. T. ruficaudus mtDNA has penetrated a population (canicaudus) treated as a race of T. amoenus. The hybrid zone is in northwestern Montana (U.S.) and southwestern Alberta (Canada). Demboski and Sullivan 2003; Good et al. 2003,2008.
Tamias cooperi [Cooper’s Chipmunk]
× Tamias townsendi [Townsend’s Chipmunk] ENHR(southeastern Canada, northeastern U.S.). These chipmunks were formerly treated as separate, but Howell (1929) noted the existence of extensive hybridization and they are now usually lumped. A long contact zone extends from southeastern British Columbia through western Washington and western Oregon.
Tamias minimus [Least Chipmunk]
× Tamias panamintinus [Panamint Chipmunk] ENHR(southwestern U.S.). Fixation of T. minimus mtDNA within populations indicates extensive past and, perhaps, ongoing hybridization between these squirrels. Reid et al. 2012.
× Tamias speciosus [Lodgepole Chipmunk] ENHR(California). Fixation of T. minimus mtDNA within populations indicates extensive past and, perhaps, ongoing hybridization between these squirrels. Reid et al. 2012.
Tamias ruficaudus [Red-tailed Chipmunk] See: Tamias amoenus. Two populations (ruficaudus, simulans), treated as races of T. ruficaudus, have two hybrid zones in the northwestern U.S. (northern Idaho and northwestern Montana). Good and Sullivan 2001; Hird et al. 2012.
Tamias panamintinus [Panamint Chipmunk] See: Tamias minimus.
Tamias speciosus [Lodgepole Chipmunk] See: Tamias minimus.
Tamias townsendi [Townsend’s Chipmunk] See: Tamias cooperi.
Tamiasciurus douglasii [Douglas’ Squirrel]
× Tamiasciurus hudsonicus [American Red Squirrel] ENHR(northwestern U.S., southwestern Canada). HPF(♂&♀). Many hybrids occur in central Oregon in the John Day River Valley (Verts and Carraway 1998). Smith (1968) and Stevens and Nellis (1974) collected probable hybrids in British Columbia and northern Washington, respectively, where potential breeding contact is also extensive. Hybrids have been observed, too, in the Blue Mountains of Oregon (Hatton and Hoffmann 1979), and on Vancouver Island (Lindsay 1982). Also see: Arbogast et al. 2001; Chavez et al. 2011; Hall 1981 (p. 466).
Tamiasciurus fremonti [Spruce Squirrel]
× Tamiasciurus hudsonicus [American Red Squirrel] ONHR(sw U.S.). Although formerly treated as separate species, these taxa were lumped after Hardy discovered they hybridize in the southwestern Rocky Mountains. T. fremonti is thus not listed by Duff and Lawson (2004). Arbogast et al. 2001 (p. 314); Hardy 1950.
Tamiasciurus hudsonicus [American Red Squirrel] See: Tamiasciurus douglasii; T. fremonti.
By the same author: Handbook of Avian Hybrids of the World, Oxford University Press (2006).
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