Peromyscus keeni (Rhoads)

Sitomys keeni Rhoads, 1894:258 .

Sitomys macrorhinus Rhoads, 1894:259 .

Peromyscus keeni Bangs, 1897:75 .

Peromyscus sitkensis Merriam, 1897:223 .

Peromyscus oreas Bangs, 1898b:84 .

Peromyscus prevostensis Osgood, 1901b:29 .

Peromyscus hylaeus Osgood, 1908:141 .

Peromyscus maniculatus oreas Osgood, 1909:51 . Peromyscus maniculatus hylaeus Osgood, 1909:53 .

Peromyscus maniculatus keeni Osgood, 1909:55 .

Peromyscus maniculatus algidus Osgood, 1909:56 .

Peromyscus maniculatus macrorhinus Osgood, 1909:57 .

Peromyscus sitkensis prevostensis Osgood, 1909:102 .

Peromyscus maniculatus interdictus Anderson, 1932:110 .

Peromyscus sitkensis oceanicus Cowan, 1935:432 .

Peromyscus sitkensis isolatus Cowan, 1935:434 .

Peromyscus maniculatus prevostensis McCabe and Cowan, 1945:187

Peromyscus maniculatus isolatus McCabe and Cowan, 1945:194 .

Peromyscus maniculatus cancrivorus McCabe and Cowan, 1945:195 .

Peromyscus maniculatus doylei McCabe and Cowan, 1945:196

Peromyscus maniculatus rubiventer McCabe and Cowan, 1945:196

Peromyscus maniculatus balaclavae McCabe and Cowan, 1945:197

Peromyscus maniculatus maritimus McCabe and Cowan, 1945:199

Peromyscus maniculatus pluvialis McCabe and Cowan, 1945:199

Peromyscus maniculatus triangularis Guiguet, 1955:B69.

Peromyscus maniculatus sartinensis Guiguet, 1955:B69.

Peromyscus maniculatus beresfordi Guiguet, 1955:B71.

Peromyscus maniculatus carli Guiguet, 1955:B72.

Holotype.— Academy of Natural Sciences, Philadelphia (catalog number 7,768); young adult, male, preserved as alcohol except skull. Original number 768 from the collection of S. N. Rhoads .

Type locality.— Canada: British Columbia; Masset, Graham Island, Queen Charlotte Islands; collected 1892 by J. H. Keen.

Subspecies.— Although we were not able to examine many of the subspecies that potentially are referable to P. keeni, based on the results of Hogan et al. (1993) and those presented herein, as well as distributional data presented in Hall (1981) we tentatively assign the following 22 subspecies recognized to P. keeni: algides, angustus, balaclavae, beresfordi, cancrivorus, carli, doylei, georgiensis, hylaeus, interdictus, insolatus, keeni, macrorhinus, maritimus, oreas, oceanicus, pluvialis, prevostensis, rubiventer, sartinensis, sitkensis, and triangularis.

Diagnosis.— Sides russet with darker brown on upperparts, underparts white. Skull heavy for the genus; nasal and rostrum short and thick; posterior nasal endings usually equaling premaxillae (Osgood 1909). Size is large for species group. Measurements obtained from Osgood (1909) and Allard and Greenbaum (1988), for several of the subspecies now assigned to P. keeni, indicate that the total length averaged 197.5 mm; (range 178–217 mm) and tail length averaged 103 mm (range 89–117 mm).

Examination of Cyt b sequences obtained in this study indicated that P. keeni differs from P. sp., P. gambelii, and P. sejugis (three closely related species to P. keeni) by 4.66%, 3.71%, and 3.97% respectively. Genetic differentiation (= 0.93%) based on DNA sequences obtained from 142 individuals of P. keeni indicated a low level of genetic divergence for members of the P. maniculatus species group. This species exhibited a similar level of genetic divergence as did P. gambelii and P. labecula, two species that occupy a similar-sized geographic area.

Distribution.— Occurs in the coastal regions (west of the Coastal and Cascade mountain ranges) in southernAlaska southward to central Washington (Hall 1981; Hogan et al. 1993; Gunn 1988; Gunn and Greenbaum 1986; Allard et al. 1987; Calhoun and Greenbaum 1991; Zheng et al. 2003; Lucid and Cook 2004). P. keeni also occurs on most of the islands in the Queen Charlotte Sound (coastal region of British Columbia) and the Alexander Archipelago (southwestern coast Alaska).

Comparison.— A member of the P. maniculatus species group. Morphological analyses (Gunn and Greenbaum 1986) indicate that samples of P. oreas (now referred to as P. keeni) were significantly larger than P. m. austerus (now referred to as P. sonoriensis), another species that occurs in the Pacific Northwest, in three external measurements including: total length, length of tail, and length of hindfoot ( P. keeni; = 199.4 mm, 106.5 mm, and 22.5 mm and P. sonoriensis; = 175.7 mm, 85.4 mm, and 20.7 mm, respectively). Similarly, Allard et al. (1987) indicated that 21 of 28 samples of P. oreas (now referred to as P. keeni) were significantly larger than those of P. m. austerus (now referred to as P. sonoriensis). In areas where P. keeni and P. maniculatus occur in sympatry, P. keeni are a habitat specialist (Songer et al. 1997) preferring a more old-growth forest habitat; whereas P. maniculatus prefer clear cut areas.

Remarks.— One hundred-eighty samples examined in this study were assigned to P. keeni . Of these samples, one from the southern portion of Prince of Wales Island, was approximately 100 km from the type locality on Queen Charlotte Island. Several studies (Robbins and Baker 1981; Rogers et al. 1984; Allard et al. 1987; Gunn and Greenbaum 1986; Calhoun and Greenbaum 1991; Hogan et al. 1993; Chirhart et al. 2001, 2005; Zheng et al. 2003), based on chromosomal, allozymic, morphologic, and sequence data, support a distinction between P. keeni (formerly recognized as P. oreas and P. sitkensis) and P. sonoriensis (formerly recognized as populations of P. maniculatus).

Gunn (1988), Gunn and Greenbaum (1986), and Hogan et al. (1993) reported two karyotypic groups of deermice from the Pacific northwest; a high FN 85–92 group that corresponded to P. oreas (now recognized as P. keeni) and a low FN group 74–78 that were assignable to P. maniculatus . No intermediate karyotypes were identified between these groups and individual mice with a high FN (85–92) typically possessed a large body size; whereas, mice with a low FN (74–78) typically possessed a smaller body size. As a result of these studies, populations formerly assigned to P. oreas and P. sitkensis were subsumed into P. keeni (Hogan et al. 1993) .

Divergence estimates obtained herein suggested that P. keeni diverged, perhaps (weakly supported node), from the common ancestor of the unnamed species (P. sp. from the Yukon region) approximately 1.12 mya. Further it appears that the P. keeni / P. sp. lineage diverged from the other extreme western forms formerly assigned to P. maniculatus ( P. gambelii and P. sejugis approximately 1.55 mya.