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Class Mammalia
Order Rodentia
Family Sciuridae

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Neotamias sp.—Chipmunks // Neotamias canipes/quadrivittatus—Gray-footed or Colorado Chipmunk // Neotamias canipes—Gray-footed Chipmunk // Neotamias minimus—Least Chipmunk // Neotamias panamintinus—Panamint Chipmunk

Neotamias A. H. Howell 1929

Synonyms. Eutamias, Tamias. Western chipmunks have widely been viewed one of three subgenera of one genus or alternately as one of three separate genera of chipmunks. A recent study (Patternson and Norris 2016) based on morphological and genomic evidence indicates that the chipmunks consist of three clades that differ from one another by as much or more than the species of Holarctic ground squirrels (sister group to the chipmunks) do from one another. For this reason, it seems best to recognize what recently have been viewed as three chipmunk subgenera (Thorington and Hoffmann 2005) as separate genera.

Chipmunks are small squirrels limited, in our region, to montane situations. In the Trans-Pecos, they are limited to the higher portions of the Guadalupe Mountains and the Sierra Diablos (Schmidly 2004). In New Mexico and Arizona, chipmunks are expected in ranges that support woodland or higher-elevation vegetation. Where more than one species occurs, there generally is an elevational division of habitat; where only a single species occurs, it generally encompasses an elevational range greater than when another species is present.

Chipmunks can be confused with other small sciurids. but dental characters and the nature of the infraorbital foramen (Figs. 1) will separate them (see figure 2 in the Sciuridae account for lower dentition differences). Within the genus, however, identification to species is difficult. Fling (1997) attempted to discriminate among the regional taxa through tooth measurements. TNeotamias minimus, a notably small-sized species, was the only taxon reliably separated from the others. Qualitative differences in teeth among the species are unknown. In light of this, identifications of species other than N. minimus must be considered highly speculative and, in practice, based on geographic considerations.

Left maxilla and p3-m2 of Neotamias from U-Bar CaveA chipmunk from U-Bar Cave (Fig. 1) is larger than any measured by Fling (1997). His largest measurement of the upper tooth row is 6.2 mm for T. cinereicollis. The specimen figured has an estimated minimum tooth row length of 7.2 mm.

Fig. 1. This Wisconsin-age Neotamias shows two characters typical of chipmunk maxillae and upper dentition. The infraorbital opening can be seen as a simple hole through the zygomatic plate (just above the masseteric tubercle in the figure), and the divergence of the lophs of M1 and M2 is clearly visible. Scale in mm.

The absence of Neotamias from the extensive late Wisconsin faunas from Dry Cave is puzzling. The hypothesized vegetation (Harris 1989) should have supported them. Neotamias minimus, for example, inhabits similar habitat in modern areas most similar to those thought to have been present at Dry Cave. Chipmunks were present at contemporaneous faunas in the southern Guadalupes and also at Dry Cave during the interstadial earlier faunas.

Literature. Fling 1997; Harris 1989; Patternson and Norris 2016; Schmidly 2004; Thorington and Hoffmann 2005.

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Neotamias sp.—ChipmunksPleistocene distribution of Tamias sp.

Chipmunks identified to genus-only recognizes the difficulty in identifying these rodents to the species level. Two records (Baldy Peak Cave and Mid Wisconsin U-Bar Cave) were originally reported as N. ? cinereicollis and N. ? dorsalis respectively. They currently are considered to be unidentifiable to species.

The record of Neotamias at Conkling Cavern appears to not be documented with specimens and is withdrawn pending further investigation.

Sites.

Late Blancan/Early Irvingtonian: Elsinore: Mimomys (Pajak et al. 1996).

Irvingtonian/Rancholabrean: Cadiz (Jefferson 2014: Cf.).

Rancholabrean: Anthony Gap Cave (UTEP); Eagle Crest (Jefferson 2014); Papago Springs Cave (Skinner 1942).

Wisconsin: Carpinteria (Wilson 1933).

Early/Early-Mid Wisconsin: Lost Valley (Harris 1993c).

Mid Wisconsin: Pacific City (Wake and Roeder 2009: cf.); Papago Springs Cave (Czaplewski and Mead et al. 1999); U-Bar Cave (Harris 1987).

Mid/Late Wisconsin: Rampart Cave (Lindsay and Tessman 1974); Diamond Valley (Springer et al. 2009).

Mid Wisconsin-Holocene: Shelter Cave (UTEP)

Late Wisconsin: Antelope Cave (Reynolds, Reynolds, Bell, and Pitzer 1991); Big Manhole Cave (Harris 1993c); Lower Sloth Cave (Logan 1983); Muskox Cave (Logan 1981); Nankoweap Canyon (Cole and Mead 1981); Tucson Mountains (Mead et al. 2005); U-Bar Cave 14-15 ka (Harris 1989); U-Bar Cave 15-18 ka (Harris 1989); U-Bar Cave 18-20 ka (Harris 1989).

Late Wisconsin/Holocene: Baldy Peak Cave (Harris 1993c); Conkling Cavern (Harris 1993c; Rejected); Kokoweef Cave (Reynolds, Reynolds, et al. 1991): 2 species, one large and one small).

Literature. Cole and Mead 1981; Czaplewski and Mead et al. 1999; Harris 1987, 1989, 1993c, 2003; Jefferson 1991b, 2014; Lindsay and Tessman 1974; Logan 1981, 1983; Mead et al. 2005;Pajak et al. 1996; Reynolds, Reynolds, et al. 1991; Reynolds, Reynolds, Bell, and Pitzer 1991; Skinner 1942; Springer et al. 2009; Wake and Roeder 2009; Wilson 1933.

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Neotamias canipes (V. Bailey 1902)/N. quadrivittatus (Say 1823)—Gray-footed or Colorado ChipmunkRegional Pleistocene distribution of Tamias canipes/quadrivittatus

Colorado Chipmunk. National Park Service photograph by Sally KingIdentification to species is based on geographic grounds. Currently, N. canipes is found in the southern mountains east of the Rio Grande Valley. The Colorado Chipmunk is primarily northern, but evidence of occurrence far to the south is seen in its presence as a relictual population in the Organ Mountains (Findley 1987). Thus, either of these two species are potentially possible.

Fig. 1. Colorado Chipmunk. National Park Service photograph by Sally King.

Sites. Mid Wisconsin: Pendejo Cave (Harris 2003).

Late Wisconsin:Dust Cave (Harris and Hearst 2012).

Literature. Findley 1987; Harris 2003; Harris and Hearst 2012.

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Neotamias canipes (V. Bailey 1902)—Gray-footed ChipmunkRegional Pleistocene distribution of Tamias canipes

Synonyms. Neotamias cinereicollis. In 1960, Fleharty split N. cinereicollis into the western populations that kept the name N. cinereicollis and resurrected the name N. canipes for populations in the southern mountains east of the Rio Grande. Dalquest and Stangl (1984b) for whatever reason used the earlier name, but made it clear that they meant the taxon that currently inhabits the Guadalupe Mountains. The assignment to species was only tentative. Likewise, the Sierra Diablo specimen is assigned to this species on the basis of distribution and that it is not N. minimus.

Neotamias canipes is limited today to the mountains from the Gallinas south to the Guadalupes (Findley 1987), and Schmidly (2004) notes that they also are recorded from the Sierra Diablo of Trans-Pecos Texas.

Sites.

Mid/Late Wisconsin/Holocene: Sierra Diablo Cave (UTEP).

Late Wisconsin/Holocene: Fowlkes Cave (Dalquest and Stangl 1984b).

Literature. Dalquest and Stangl 1984b; Findley 1987; Fleharty 1960; Schmidly 2004.

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Neotamias merriami (J. A. Allen 1889)—Merriam's ChipmunkPleistocene distribution of Neotamias merriami

Sites.

Mid/Late Wisconsin: Rancho La Brea (Whistler 1989: cf.).

Literature. Whistler 1989.

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Neotamias minimus Bachman 1839—Least ChipmunkPleistocene distribution of Tamias minimus

Least Chipmunk. National Park Service photograph by Sally KingThe Least Chipmunk has relictual distributions in the southeastern New Mexico mountains, but is common in the northern mountains. There also is a relictual population in the White Mountains of eastern Arizona.

Fig. 1. Least Chipmunk. National Park Service photograph by Sally King.

Neotamias minimus is enough smaller than other regional species of Neotamias to allow reasonably secure species identification. The Bat Cave occurrence is of special interest because it lies about halfway between western (White Mountains of Arizona) and eastern (Sierra Blanca/Sacramento Mountains of New Mexico), demonstrating rather nicely continuous distribution between present-day highlands.

Sites.

Rancholabrean: Cool Water Coal Gasification Solid Waste Site (Jefferson 1991b: cf.).

Mid Wisconsin: Pendejo Cave (Harris 2003).

Late Wisconsin: Dust Cave (Harris and Hearst 2012); Sheep Camp Shelter (Gillespie 1985: cf.).

Late Wisconsin/Holocene: Bat Cave (Scarbrough 1986); Kokoweef Cave (Reynolds, Reynolds, et al. 1991); SAM Cave (Rogers et al. 2000).

Literature. Gillespie 1985; Harris 1993c, 2003; Harris and Hearst 2012; Jefferson 1991b; Reynolds, Reynolds, et al. 1991; Scarbrough 1986; Rogers et al. 2000.

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Neotamias panamintinus (Merriam 1893)—Panamint ChipmunkRegional Pleistocene distribution of Tamias panamintinus

Sites.

Late Wisconsin: Antelope Cave (Reynolds, Reynolds, Bell, and Pitzer 1991).

Literature. Reynolds, Reynolds, Bell, and Pitzer 1991.

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Last Update: 14 Jul 2018