Peromyscus truei
Pinyon Deermouse
(Peromyscus truei) | |
---|---|
Range | |
![]() | |
Taxonomic classification | |
Order: | Rodentia |
Suborder: | Supramyomorpha |
Infraorder: | Myomorphi |
Superfamily: | Muroidea |
Family: | Cricetidae |
Subfamily: | Neotominae |
Tribe: | Peromyscini |
Genus: | Peromyscus |
Binomial details | |
Peromyscus truei (Shufeldt, 1885) |
Description
From Hoffmeister (1981) for Arizona: "Pinyon mice are large-eared, medium-sized mice. Color varies from a pale yellowish-brown (P. t. chlorus) to brownish black (P. t. dyselius and gratus) and the fur is long and silky. The dorsal tail stripe is slightly darker than the back. The tail is covered with short hairs except at the tip where longer hairs project. An ochraceous pectoral spot may be present or absent. Mice of the species P. truei have relatively and actually large ears, with the ear measured from the notch equal to or longer than the hind foot in most populations. Total length averages about 190 to 200 mm. The tail is longer than the head and body in populations west of the Sierra Nevadas, Baja California, and mainland Mexico; the tail is shorter than the body in most United States populations east of the Sierra Nevadas and Cascade Mountains. The hindfoot in most populations is 22 mm or more in length."
From Schmidly & Bradley (2016) for Texas: "A moderately sized, large-eared deermouse; tail as long as, or slightly longer than, head and body and scantily haired; upper parts ochraceous buff mixed with dusky, giving an overall effect of cinnamon or tawny olive in unworn pelage and wood brown in worn pelage; the pronounced lateral line is ochraceous buff; sides of face and nose grayish; ears dusky; feet and underparts white; tail dark above, white below."
From Armstrong et al. (2010) for Colorado: "This is a large, buff-colored, long-eared mouse with a tail slightly shorter than the head and body (based on specimens from our area). The distinctive ears are the longest of any species of Peromyscus in Colorado, usually exceeding 22 mm. The dorsal color is pale buff to rich grayish brown, with the tail distinctly bicolored. The venter is white but the hairs have gray bases. The hindfeet are either white or pale grayish. The fur is long and soft. The tail is covered with short hairs generally concealing the scales. Hairs at the tip of the tail are longer."
From KE Mabry (personal communication, March 12, 2024) for Napa County, California: "In southeastern Napa County, California, Peromyscus truei have very short ears. Ear:HFL [ear to hindfoot length ratio] seems to be a reliable character elsewhere, but not there. [In southeastern Napa County], adult Peromyscus boylii generally have ears that are 17-19 mm and adult Peromyscus truei generally have ears that are >20 mm."
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 (Coconino and Apache cos.) | Hoffmeister (1986) | 173–210 (n=40) | 80–110 (n=40) | 21–26 (n=40) | 23–28 (n=40) | |
California | Jameson & Peeters (2004) | 177–195 | 87–98 | 22–24 | 18–27 | 20–29 |
Colorado | Armstrong et al. (2010) | 187–198 | 90–103 | 23–25 | 23–30 | 20–28 |
not reported | Ceballos (editor, 2014) | 205–221 | 101–127 | 23–24 | 21–24 | 15–35 |
Texas | Schmidly & Bradley (2016) | 204 | 100 | 22.5 | 23.5 | 24–39 |
Color variation
This section shows some of the color variation present in Peromyscus truei. The location is provided for reference only. The individual shown does not necessarily represent the only color variant within the local population.
-
Arizona, Apache County (ruler was added to image and is an approximation)
-
California, Madera County
Skull
From Hoffmeister (1981): "Greatest length of skull in adults is usually between 27.0 and 30.0 mm and alveolar length of the maxillary toothrow between 4.2 and 4.5 mm. The braincase is large and vaulted and the zygomatic arches are weak, do not bulge laterally, and converge anteriorly. A mesoloph is present in M1 and M2. In m1 and m2 a remnant of a mesolophid or a mesostylid or what Schmidly (1973) calls an entolophulid and ectostylid, respectively, may occasionally be present."
From Armstrong et al. (2010) for Colorado: "The skull is large, with large, inflated auditory bullae. Greatest length of skull is 28–29 mm, similar to that of the rock mouse [Peromyscus nasutus] but relatively broader and with a less elongate rostrum."
-
Dorsal view of the skull of Peromyscus truei. -
Lateral view of the skull of Peromyscus truei. Lower mandible not shown. -
Ventral view of the skull of Peromyscus truei. -
Upper incisors of Peromyscus truei. -
Dorsal view of the lower mandible of Peromyscus truei. -
Arrows point to the mesolophs present on both the first and second upper molars (M1 and M2) in Peromyscus truei. -
This illustration of the left lower m2 molar from Hooper (1957) is shown to assist with identifying a mesolophid or mesostylid (or what Schmidly, 1973, calls an entolophulid and ectostylid), which may occasionally be present on the m1 and m2 (first and second lower molars) of Peromyscus truei.
Similar species
Peromyscus truei is most often confused with Peromyscus boylii, P. californicus, P. leucopus, and P. nasutus.
Comparison with Peromyscus boylii
From Kalcounis-Rueppell & Spoon (2009): East of the Sierra Nevada, P. boylii can be differentiated from P. truei by a length of tail > total length of body (Schmidly, 1977; Davis and Schmidly, 1994). Kalcounis-Rueppell & Spoon (2009) add that "west of the Sierra Nevada, where the tail of P. truei is longer than its head and body, P. boylii is distinguished from P. truei by ears that are 70–80% as long as the hind foot rather than longer than the hind foot, by a tail that is less heavily haired but with more pronounced annulations, and by auditory bullae that are less inflated (Hoffmeister 1981)." However, KE Mabry (personal communication, March 12, 2024) found that "in southeastern Napa County, California, Peromyscus truei have very short ears. Ear:HFL [ear to hindfoot length ratio] seems to be a reliable character elsewhere, but not there. [In southeastern Napa County], adult Peromyscus boylii generally have ears that are 17-19 mm and adult Peromyscus truei generally have ears that are >20 mm. I've compared ear length for genotyped animals, and the cut-off seems to be 19.5—above that, they are *almost* all Peromyscus truei and below they are *almost* all Peromyscus boylii. I also look at nose shape—Peromyscus boylii has a "pointy" nose and Peromyscus truei is more rounded. But there are definitely animals that are not clearly one or the other in hand."
-
Peromyscus truei from Madera County, California -
Peromyscus truei from Apache County, Arizona. As several authors have noted, the length of the tail < total body length in individuals east of the Sierra Nevada. Note: ruler was added to the image and represents an approximation. -
Brush Deermouse (Peromyscus boylii)
Comparison with Peromyscus californicus
From Hoffmeister (1981): "Peromyscus truei occurs with P. californicus in parts of its range and differs from it in overall smaller size, shorter hindfoot, smaller skull and shorter toothrow, presence rather than absence of mesolophs of the first and second upper molars, and in differences in the number of kinds of chromosomes."
Comparison with Peromyscus crinitus
The Canyon Deermouse (Peromyscus crinitus) can be differentiated from Peromyscus truei by its relatively long tail that has a pronounced terminal tuft. The tail of P. truei is scantily haired and lacks a pronounced terminal tuft. Both species have large ears. In P. crinitus, the ear measured from the notch is about equal to the length of the hind foot. In P. truei, the ear is equal to or longer than the hind foot in most populations.
-
Peromyscus truei -
Canyon Deermouse (Peromyscus crinitus)
Comparison with Peromyscus fraterculus
The Northern Baja Deermouse (Peromyscus fraterculus) can be distinguished from Peromyscus truei by its shorter ears (shorter than the length of the hind foot) and long, sparsely haired tail. Where the two species are sympatric, the large ears of Peromyscus truei are typically equal to or longer than the hind foot in most populations and the tail is covered with short hairs except at the tip where longer hairs project.
-
Peromyscus truei -
Northern Baja Deermouse (Peromyscus fraterculus). Photograph by Patricia Simpson.
Comparison with Peromyscus leucopus
From Hoffmeister (1981): "Peromyscus truei usually does not occupy the same areas as P. leucopus, but where it does P. truei is larger, especially the ear and the tail, the tail is more heavily haired at the tip, the skull is larger, the auditory bullae are much more inflated, and the zygomatic arches are less strongly bowed outward."
Peromyscus truei. Note: ruler was added to the image and represents an approximation. White-footed Deermouse (Peromyscus leucopus) Dorsal view of the skull of Peromyscus truei. Dorsal view of the skull of Peromyscus leucopus.
Comparison with Peromyscus nasutus
Hoffmeister (1981) states that Peromyscus truei can be differentiated from P. nasutus by: "a combination of color features. In [P. nasutus], the coloration of the dorsum in adults often is grayish-black, somewhat similar to the juvenile pelage, the color along the lateral line has very little ochraceous color, and the top of the head in adults is often grayish. In addition, in P. truei, the auditory bullae are relatively more inflated, the toothrow is shorter, and chromosomes differ in the number of kinds."
Peromyscus truei. Note: ruler was added to the image and represents an approximation. -
Northern Rock Deermouse (Peromyscus nasutus)
References
Armstrong DM, Fitzgerald JP, Meaney CA. 2010. Mammals of Colorado, Second Edition. Denver (CO, USA): University Press of Colorado.
Ceballos G, editor. 2014. Mammals of Mexico. Baltimore (MD, USA): Johns Hopkins University Press.
Hoffmeister DF. 1981. Peromyscus truei. Mammalian Species (161): 1-5.
Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.
Hooper ET. 1957. Dental patterns in mice of the genus Peromyscus. Miscellaneous publications University of Michigan Museum of Zoology 99: 1-59.
Jameson EW, Peeters HJ. 2004. Mammals of California (No. 66). Berkeley (CA, USA): University of California Press.
Schmidly DF. 1973. The systematic status of Peromyscus comanche. Southwestern Naturalist 18:269-278.
Schmidly DJ, Bradley RD. 2016. The mammals of Texas. Austin (TX, USA): University of Texas Press.
Shufeldt RW. 1885. Description of Hesperomys truei, a New Species Belonging to the Subfamily Murinae. Proceedings of the United States National Museum, 8, 405.