Ammospermophilus nelsoni

Nelson's Antelope Squirrel
(*Ammospermophilus nelsoni*)
Nelson's Antelope Squirrel (Ammospermophilus nelsoni)
Range
Taxonomic classification
Order:	Rodentia
Suborder:	Sciuromorpha
Family:	Sciuridae
Subfamily:	Xerinae
Tribe:	Marmotini
Genus:	Ammospermophilus
Binomial details
	Ammospermophilus nelsoni (C. H. Merriam, 1893)
Other resources
	Full taxonomic details at MDD

The Nelson's Antelope Squirrel (Ammospermophilus nelsoni) is a ground squirrel endemic to California. It is found in the San Joaquin Valley.

Description

From Best et al. (1990): "The upper parts are dull yellowish-brown or huffy-clay color, as are the outer surfaces of the legs. There is a pale stripe on each side reaching from behind the shoulder to the rump . The underparts, feet, and eyelids are soiled whitish, and the feet are suffused with buffy. Above, the proximal one-third of the tail is buffy-clay color like the back; the distal two-thirds is mixed black and whitish with a whitish border. Below, the tail is soiled or buffy whitish, bordered on the distal two-thirds with a broad subterminal black band, and edged with whitish. There also is a narrow black zone at the base of the tail hairs. The upper parts are rather coarsely lined with black hairs that are absent from the legs, giving the legs a slightly different tint, and in some the ground color of the legs and sides just above the forelegs is different, being suffused with dull buffy-ochraceous (Merriam, 1893)."

Museum specimens

Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893.
Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893.
Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893.

External measurements

Length measurements are in millimeters (mm) and weight measurements are in grams (g), unless stated otherwise. If available, the sample size (n=) is provided. If a range is not provided and n= is not given, then the listed measurement represents an average.

Part of range	Reference	Total length	Tail length	Hindfoot length	Ear length	Mass
California	Best et al. (1990)	234–267 (males); 230–256 (females)	66–78 (males); 67–78 (females)	40–44 (males); 37–43 (females; Taylor, 1916)	dry: 8–9 (males); 8–9.5 (females; Howell, 1938)
California	Jameson & Peeters (2004)	218–240	63–79	40–43	8–9

Variation

From Best et al. (1990): "Geographic variation primarily is in coloration (Taylor, 1916) and size. Specimens from the southern San Joaquin Valley are smaller and less yellowish in coloration, with a gradual increase in size to the largest, more yellow northern forms (Hafner, 1981)."

Skull

Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893. Dorsal view of the skull.
Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893. Ventral view of the skull.
Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893. Lateral view of the skull.
Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893. Dorsal view of the mandible.
Holotype: USNM 54651. Ammospermophilus nelsoni. Adult male. Tipton, San Joaquin Valley, Tulare Count], California. Collected 24 June 1893. Lateral view of the left mandible.

Similar species

From Best et al. (1990): "Ammospermophilus nelsoni differs from A. l. leucurus in being larger and more buffy (less grayish), and in having more widely spreading zygomatic arches (Hall, 1981). The skull is similar to that of A. leucurus, but longer and broader; auditory bullae are conspicuously larger, more inflated, and distinctly corrugated. The corrugations are due to the presence of two transverse constrictions, marking the position of vascular canals; they are faint or absent in A. leucurus and A. harrisii. The rostrum and nasal bones are somewhat longer, and the upper incisors and first upper premolar are larger than in A. leucurus (Merriam, 1893)."

Nelson's Antelope Squirrel (Ammospermophilus nelsoni) photographed in California by Paul Donahue.
White-tailed Antelope Squirrel (Ammospermophilus leucurus) photographed by lonnyholmes in Clark County, Nevada.

References

Best TL, Titus AS, Lewis CL, Caesar K. 1990. Ammospermophilus nelsoni. Mammalian Species (367):1-7.

Hafner DJ. 1981. Evolution and historical zoogeography of antelope ground squirrels, genus Ammospermophilus (Rodentia: Sciuridae). Unpublished Ph.D. dissert., The University of New Mexico, Albuquerque, 225 pp.

Hall ER. 1981. The mammals of North America. Second edition. John Wiley & Sons, New York.

Howell AH. 1938. Revison of the North American ground squirrels, with a classification of the North American Sciuridae. North American Fauna 56:1-256

Merriam, C.H. 1893-12-28. Descriptions of eight new ground squirrels of the genera Spermophilus and Tamias from California, Texas, and Mexico. Proceedings of the Biological Society of Washington 8:129-138.

Taylor WP. 1916. A new spermophile from the San Joaquin Valley, California, with notes on Ammospermophilus nelsoni nelsoni Merriam. University of California Publications in Zoology 17:15-20.