Dipodomys nitratoides
San Joaquin Kangaroo Rat
(Dipodomys nitratoides) | |
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Range | |
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Taxonomic classification | |
Order: | Rodentia |
Suborder: | Supramyomorpha |
Infraorder: | Castorimorphi |
Family: | Heteromyidae |
Subfamily: | Dipodomyinae |
Genus: | Dipodomys |
Binomial details | |
Dipodomys nitratoides Merriam, 1894 |
Description
From Best (1991): "Dipodomys nitratoides is one of the smallest members of the genus (Best, in press). The upper parts are uniform fulvous or clay color, darkened with sepia from the abundant admixture of black-tipped hairs, and darkest on the head. Facial crescents are dusky and meet over the bridge of the nose. The upper and lower tail stripes are sooty blackish, meeting along the terminal one-third, thus interrupting the white side stripes. The dorsal tail stripe is darker than the back and the crested part of the tail is the same color as the back. The ventral tail stripe is dull fulvous, continuous to the end of the tail. The inner aspect of hind legs to heel are dull fulvous, and the under parts of the thigh stripe are white. The posterior aspect of the ankles and lower leg is black. The sides and flanks are tinged with ochraceous-buff. There are black crescents at the base of the whiskers that are sharply defined and meet in a median line, so that the bridge of the nose is black. The superciliary stripe is whitish and not interrupted. The under parts are silky white. The spot over the eye is obscured by dark-tipped hairs (Merriam, 1894). There is little difference in pelage shade between juveniles and adults. However, there is a difference in texture of the coat; juvenile pelage is finer than that of adults (Hoffmann, 1975)."
From Jameson & Peeters (2004): A somewhat small, rather dark kangaroo rat with four toes on its hind foot. It has a relatively short, buff-tipped tail.
For geographic variation, see Patton et al. (2019) in the References section.
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 |
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California | Jameson & Peeters (2004) | 211–253 | 120–152 | 33–37 | 39–47 | |
California (Fresno) | Patton et al. (2019) | 211–245 (n=20) | 122–147 (n=20) | 33–35 (n=20) | ||
California (Tipton) | Patton et al. (2019) | 212–253 (n=49) | 114–152 (n=49) | 31–37 (n=52) |
Skull
Similar species
From Best (1991): "Several congeners occur sympatrically or near the range of D. nitratoides. D. merriami is not sympatric, but is similar morphologically (Hall, 1981). The dark dorsal and ventral tail stripes in D. nitratoides are broader than the white lateral tail stripes; conversely, in D. merriami the white lateral tail stripes are always broader than even the dark dorsal one, and the dark ventral one is narrower or almost lacking (Grinnell, 1922). The baculum of D. nitratoides is much longer (13.3 mm) than that of D. merriami (10.8 mm), and is among the longest in the genus (Best and Schnell, 1974). D. ingens, D. panamintinus, D. heermanni, and D. microps have five toes on the hind foot instead of four as in D. nitratoides; they also are much larger (Hall, 1981)."
References
Grinnell J. 1922. A geographical study of the kangaroo rats of California. University of California Publications in Zoology 24: 1-124.
Hall ER. 1981. The mammals of North America. Second ed. John Wiley and Sons, New York, 1:1-600
Hoffman WM. 1975. Geographic variation and taxonomy of Dipodomys nitratoides from the California San Joaquin Valley. M.A. thesis, California State University, Fresno, 75 pp.
Jameson EW, Peeters HJ. 2004. Mammals of California (No. 66). Berkeley (CA, USA): University of California Press.
Merriam CH. 1894. Preliminary descriptions of eleven new kangaroo rats of the genera Dipodomys and Perodipus. Proceedings of the Biological Society of Washington 9: 109-116.
Patton JL, Williams DF, Kelly PA, Cypher BL, Phillips SE. 2019. Geographic variation and evolutionary history of Dipodomys nitratoides (Rodentia: Heteromyidae), a species in severe decline. Journal of Mammalogy 100(5):1546-1563. https://doi.org/10.1093/jmammal/gyz128.