Peromyscus attwateri
| Texas Deermouse
(Peromyscus attwateri) | |
|---|---|
| Range | |
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| Taxonomic classification | |
| Order: | Rodentia |
| Suborder: | Supramyomorpha |
| Infraorder: | Myomorphi |
| Superfamily: | Muroidea |
| Family: | Cricetidae |
| Subfamily: | Neotominae |
| Tribe: | Peromyscini |
| Genus: | Peromyscus |
| Binomial details | |
| Peromyscus attwateri J. A. Allen, 1895 | |
| Other resources | |
| Full taxonomic details at MDD | |
The Texas Deermouse (Peromyscus attwateri) is a medium-sized deer mouse found in rugged, rocky hillsides typically in juniper or cedar breaks. Many species of deer mice are difficult to differentiate without careful measurement and examination of the molar teeth. With the help of good photographs, it may be possible to narrow the list of potential species.
Description
From Schmidley & Bradley (2016) for Texas: "A medium-sized Peromyscus with the tail about as long as (or slightly longer than) the head and body, moderately haired, darker above than below (but not sharply bicolor) and usually with a terminal tuft; hind foot large (24–27 mm); ankles usually dark or dusky; dorsal color near sayal brown, darker and mixed with blackish along midline; sides pinkish cinnamon; ventral color pure white, the bases of the hairs plumbeous."
From Best & Hunt (2020) for the southeastern US: “This is a medium-sized deermouse that is grayish-brown to dark brown on the dorsum, paler brown on the sides, and sometimes with a dark, longitudinal, mid-dorsal band. A yellow-orange lateral stripe separates the dorsum from the white or cream-colored ventrum. Color is somewhat brighter in summer and drabber during winter. Eyes and ears are prominent, feet are large (24–27 mm long) and white, and ankles are dark. The tail is about the length of head and body combined, is indistinctly bicolored, and usually has a distinct tuft at the end.”
Museum type specimens
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Holotype: AMNH MO-8712, AMNH MS-10401. Peromyscus attwateri. Female. Kerr County, Texas. Collected 12 March 1895. Dorsal view. -
Holotype: AMNH MO-8712, AMNH MS-10401. Peromyscus attwateri. Female. Kerr County, Texas. Collected 12 March 1895. Ventral view. -
Holotype: AMNH MO-8712, AMNH MS-10401. Peromyscus attwateri. Female. Kerr County, Texas. Collected 12 March 1895. Lateral view.
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 |
|---|---|---|---|---|---|---|
| Texas | Schmidly & Bradley (2016) | 198 | 103 | 25 | 25–35 |
Color variation
From Schmidly (1974): "Brown (1963) documented developmental and seasonal molts in P. attwateri from southwestern Missouri. There are five distinct pelages in the life cycle of P. attwateri: juvenile pelage (duration 5 weeks), subadult pelage (7 weeks), young adult pelage (3 weeks), intermediate pelage (7 weeks), and full adult pelage. Two annual molts occur in natural populations of attwateri; one in spring and a second in autumn. The summer and winter pelages differ in color; the winter pelage is a drab brown and the summer pelage a bright cinnamon brown."
Skull
From Schmidly & Bradley (2016): "Length of maxillary tooth row ≥4 mm; each large upper and lower molar has an accessory loph."
From Schmidly (1974): "Skull large (27.6 to 30.4 mm); braincase elongated and wide, but not rounded; maxillary region of zygoma heavy; zygomatic arches parallel and not converging anteriorly; nasals short in relation to length of rostrum; pterygoid fossa large; auditory bullae medium, larger than in P. maniculatus and P. leucopus but smaller than in P. truei; interorbital constriction smooth and not angular; infraorbital canal wide; rostrum depressed anteriorly.... interorbital constriction 4.0 to 4.8; zygomatic breadth 13.6 to 15.4; length of palatine foramen 5.5 to 6.4; depth of skull 9.2 to 10.3."
NEON01IGI. Peromyscus attwateri. Dorsal view of the skull. 
NEON01IGI. Peromyscus attwateri. Ventral view of the skull. 
NEON01IGI. Peromyscus attwateri. Lateral view of the skull. 
NEON01IGI. Peromyscus attwateri. Dorsal view of the lower jaw. 
NEON01IGI. Peromyscus attwateri. Upper incisors. 
NEON01IGI. Peromyscus attwateri. Arrows point to the accessory lophs on each of the first and second upper molars. 
NEON01IGI. Peromyscus attwateri. Arrows point to the accessory lophs on the first and second upper molars. 
NEON01IGI. Peromyscus attwateri. Arrows point to the accessory lophs on the first and second lower molars.
Similar species
Comparison with Peromyscus boylii
Peromyscus attwateri is similar in appearance to the Brush Deermouse (Peromyscus boylii) and was formerly treated as a subspecies of P. boylii. In Texas, Schmidly & Bradley (2016) note that "the most useful morphological features available in the field, and to those not trained in cytogenetics, are the larger hind foot (24–27 mm in attwateri and 20–23 mm in Texas-taken boylii) and the structure of the molar teeth. In attwateri, an accessory loph is present in both the upper and lower molars, but that structure is absent from the lower molars of boylii."
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Texas Deermouse (Peromyscus attwateri) -
Brush Deermouse (Peromyscus boylii) -
Arrows point to the accessory lophs in the first and second lower molars in the Texas Deermouse (Peromyscus attwateri). -
The lower molars of the Brush Deermouse (Peromyscus boylii) lack accessory lophs, unlike in Peromyscus attwateri.
Comparison with Peromyscus eremicus
The Cactus Deermouse (Peromyscus eremicus) differs from P. attwateri in less heavily haired tail and upper molars 1-2 without mesolophs. The coloration of the pelage for P. eremicus varies among the subspecies and even among different populations and is not always a reliable character (Veal & Caire, 1979). Pelage color for P. eremicus at one locality may not be diagnostic at another locality.
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Texas Deermouse (Peromyscus attwateri) -
Cactus Deermouse (Peromyscus eremicus) NEON01IGI. Texas Deermouse (Peromyscus attwateri). Arrows point to the accessory lophs on the first and second upper molars. -
Holotype: USNM 20018/35413. Cactus Deermouse (Peromyscus eremicus). Upper molars. Upper molars 1-2 usually without a mesoloph (Hoffmeister, 1986). NEON01IGI. Texas Deermouse (Peromyscus attwateri). Arrows point to the accessory lophs on the first and second lower molars. -
Holotype: USNM 20018/35413. Cactus Deermouse (Peromyscus eremicus). Lower molars lack accessory lophs, unlike in Peromyscus attwateri.
Comparison with Peromyscus laceianus
Bradley et al. (2015) also noted that P. attwateri and the Northern White-ankled Deermouse (Peromyscus laceianus) are similar in appearance and may easily be confused in Texas: "From P. attwateri, P. laceianus differs in smaller size (particularly in length of hind foot); paler color; white instead of dusky ankles; more sharply bicolored tail; smaller bullae; shorter incisive foramen; truncate instead of rounded posterior tip of nasals; shorter toothrow; smaller, more weakly developed mesopterygoid process; baculum with long cartilaginous spine at distal end instead of a short spine; 9–10 large chromosomes rather than 7–8."
NEON01IGI. Texas Deermouse (Peromyscus attwateri). Dorsal view of the skull. -
Holotype: USNM 97063.Northern White-ankled Deermouse (Peromyscus laceianus). Dorsal view of the skull.
Comparison with Peromyscus truei
From Schmidly & Bradley (2016) for where they may co-occur Texas: "Peromyscus attwateri can be distinguished from P. truei by its longer hind foot (>23 mm rather than <23 mm) and shorter ears (<21 mm rather than >22 mm)."
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Texas Deermouse (Peromyscus attwateri) -
Pinyon Deermouse (Peromyscus truei)
Comparison with other Peromyscus species
Peromyscus attwateri can be differentiated from the Southern Deermouse (Peromyscus labecula), the White-footed Deermouse (Peromyscus leucopus), and the Western Deermouse (Peromyscus sonoriensis) by a length of tail > total length of body. In addition to having short tails, P. sonoriensis also have strongly bicolored tails, whereas P. attwateri does not.
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Texas Deermouse (Peromyscus attwateri) -
White-footed Deermouse (Peromyscus leucopus) -
Western Deermouse (Peromyscus sonoriensis)
References
Allen, J.A. 1895-11-08. Descriptions of new American mammals. Bulletin of the American Museum of Natural History 7(10):327-340.
Best TL, Hunt JL. 2020. Mammals of the southeastern United States. Tuscaloosa (AL, USA): University Alabama Press.
Bradley RD, Schmidly DJ, Amman BR, Platt RN, Neumann KM, Huynh HM, ... & Ordóñez-Garza N. 2015. Molecular and morphologic data reveal multiple species in Peromyscus pectoralis. Journal of Mammalogy 96(2): 446-459.
Brown LN. 1963. Maturational molts and seasonal molts in Peromyscus boylei. American Midland Naturalist 70: 466-46.
Hoffmeister DF. 1986. Mammals of Arizona. Tucson (AZ, USA): University of Arizona Press.
Schmidly DJ. 1974. Peromyscus attwateri. Mammalian Species (48): 1-3.
Schmidly DJ, Bradley RD. 2016. The mammals of Texas. Austin (TX, USA): University of Texas Press.
Veal R, Caire W. 1979. Peromyscus eremicus. Mammalian species (118): pp.1-6.