Neotoma mexicana

Mexican Woodrat
(*Neotoma mexicana*)
Mexican Woodrat (Neotoma mexicana)
Range
Taxonomic classification
Order:	Rodentia
Suborder:	Supramyomorpha
Infraorder:	Myomorphi
Superfamily:	Muroidea
Family:	Cricetidae
Subfamily:	Neotominae
Tribe:	Neotomini
Genus:	Neotoma
Binomial details
	Neotoma mexicana S. F. Baird, 1855
Other resources
	Full taxonomic details at MDD

The Mexican Woodrat (Neotoma mexicana) is a medium-sized woodrat. It occupies a variety of habitats including grasslands, shrublands, and forests, prefering rocky environments, slopes, and cliffs.

Description

For Colorado, from Armstrong et al. (2010): "The Mexican woodrat is a medium-sized woodrat. Dorsal color of animals from the foothills of the Front Range is usually dark gray, often washed with black. Animals from southwestern Colorado are more grayish buff on the dorsum, whereas those from the San Luis Valley and southeastern Colorado are grayish yellow to gray-buff. The sides are paler grayish buff. The underparts are whitish with all hairs gray at their bases. There is typically a dusky line or ring around the mouth. The short-haired tail is distinctly bicolored, blackish above and whitish gray below. The feet are white."

From Hoffmeister (1986): "A species of Neotoma with the hairs in the throat region plumbeous-colored at their bases (not white-throated), M1 with the antero-medial (=anterointernal) fold deep, upperparts of adults appear grizzled, underparts plumbeous or gray, dark-colored fur does not extend onto dorsum of hind foot."

Museum images

Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult female. San Francisco Mountain, Coconino County, Arizona. Collected 16 August 1889.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult female. San Francisco Mountain, Coconino County, Arizona. Collected 16 August 1889.

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
Arizona (Chiricahua Mtns.)	Hoffmeister (1986)	males: 331 (n=2); females: 302–350 (n=4)	males: 151 (n=2); females: 130–166 (n=4)	males: 36 (n=2); females: 30–34 (n=4)	males: 28 (n=2); females: 23.5–28 (n=4)
Arizona (Graham Mtns.)	Hoffmeister (1986)	males: 320–349 (n=5); females: 286 (n=3)	males: 142–158 (n=5); females: 133 (n=3)	males: 32–37 (n=5); females: 32–36 (n=3)	males: 25–28 (n=5); females: 25–26 (n=3)
Arizona (Santa Catalina Mtns.)	Hoffmeister (1986)	males: 330–346 (n=3); females: 318 (n=1)	males: 150–165 (n=3); females: 152 (n=1)	males: 35–36 (n=3); females: 35 (n=1)
Arizona (vicinity Flagstaff and Williams)	Hoffmeister (1986)	males: 337–357 (n=7); females: 325–382 (n=8)	males: 145–159 (n=7); females: 135–170 (n=8)	males: 35–38 (n=7); females: 34–39 (n=8)	males: 26–29 (n=7); females: 27–32 (n=8)
Arizona (White Mtns.)	Hoffmeister (1986)	males: 311–335 (n=4); females: 311–335 (n=7)	males: 125–151 (n=4); females: 127–148 (n=7)	males: 34–36 (n=4); females: 32–37 (n=7)	males: 25–28 (n=4); females: 25–30 (n=7)
Colorado	Armstrong et al. (2010)	297–380	124–178	29–38	26–28	149–255
not reported	Ceballos (editor, 2014)	285–421	133–216	33–41	25–30	151–253
Texas	Schmidly & Bradley (2016)	300	125	28		140–185

Skull

From Armstrong et al. (2010): "The skull is robust and often somewhat arched in the interorbital region. The maxillo-vomerine notch divides the nasal septum. The anterior palatal spine has a sharp tip. In most specimens the antero-internal fold of M1 [first upper molar] is deep, extending more than halfway across the crown."

The holotype for Neotoma mexicana (USNM A 1674) is archived at the Smithsonian National Museum of Natural History and images are available. However, the skull is damaged. Instead, images of one of the subspecies are shown below.

Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult female. San Francisco Mountain, Coconino County, Arizona. Collected 16 August 1889. Dorsal view of the skull.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult female. San Francisco Mountain, Coconino County, Arizona. Collected 16 August 1889. Ventral view of the skull.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult female. San Francisco Mountain, Coconino County, Arizona. Collected 16 August 1889. Lateral view of the skull.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult female. San Francisco Mountain, Coconino County, Arizona. Collected 16 August 1889. Dorsal view of the mandible.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult female. San Francisco Mountain, Coconino County, Arizona. Collected 16 August 1889. Lateral view of the left mandible.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult. Upper molars. Arrows point to the anteromedial flexus of the anteroloph of each upper molar (M1), which is deeply notched.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult. Lower molars.

Similar species

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Comparison with Neotoma albigula

From Hoffmeister (1986): "N. albigula differs from Neotoma mexicana in hairs on the throat white to their bases rather than dusky, antero-internal reentrant angle of M1 shallow rather than extending more than half way across the crown, premaxillaries extending farther posteriorly relative to end of nasals."

White-throated Woodrat (Neotoma albigula)
Mexican Woodrat (Neotoma mexicana)
Holotype: USNM 186485. Neotoma albigula albigula. Adult. Upper molars. Arrows point to the anteromedial flexus of the anteroloph of each upper molar (M1), which is shallow.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult. Upper molars. Arrows point to the anteromedial flexus of the anteroloph of each upper molar (M1), which is deeply notched.

Comparison with Neotoma devia

The Arizona Woodrat (Neotoma devia) does not have an antero-internal fold in the first upper molar (M1), as in Neotoma mexicana.

Holotype: USNM 226376. Neotoma devia. Adult. Upper molars. Arrows point to the anteromedial flexus of anteroloph of each upper molar (M1), which is shallow to obsolete except in very young individuals (Patton et al., 2007).
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult. Upper molars. Arrows point to the anteromedial flexus of the anteroloph of each upper molar (M1), which is deeply notched.

Comparison with Neotoma lepida

From Hoffmeister (1986): N. lepida "does not have an antero-internal fold in M1 (as in N. mexicana). From Armstrong et al. (2010): "From Neotoma mexicana it differs in having a much less arched skull, some hairs on the chest white to their bases, and a blunt anterior palatal spine."

Holotype: USNM 25739/33139. Neotoma lepida lepida. Adult. Upper molars.
Holotype: USNM 17692/24628. Neotoma mexicana pinetorum. Adult. Upper molars. Arrows point to the anteromedial flexus of the anteroloph of each upper molar (M1), which is deeply notched.

References

Armstrong DM, Fitzgerald JP, Meaney CA. 2010. Mammals of Colorado, Second Edition. Denver (CO, USA): University Press of Colorado.

Baird SF. 1855-06-15. Characteristics of some new species of Mammalia, collected by the U. S. and Mexican Boundary Survey, Major W. H. Emory, U. S. A. Commissioner. Proceedings of the Academy of Natural Sciences of Philadelphia 7:331-333.

Ceballos G, editor. 2014. Mammals of Mexico. Baltimore (MD, USA): Johns Hopkins University Press.

Cornely JE, Baker RJ. 1986. Neotoma mexicana. Mammalian species (262):1-7. https://doi.org/10.2307/3504054

Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.

Schmidly DJ, Bradley RD. 2016. The mammals of Texas. Austin (TX, USA): University of Texas Press.