Part 5

Pitymys pinetorum scalopsoides (Audubon and Bachman)

1841. Arvicola scalopsoides Audubon and Bachman, Proc. Acad. Nat. Sci. Philadelphia, 1:97, type from Long Island, New York.

1912. Pitymys pinetorum scalopsoides Miller, U. S. Nat. Mus. Bull., 79:229, December 31.

Hanson (Trans. Wisconsin Acad. Sci., Arts, and Letters, 36:124, 1944) reported two pine mice from near Prairie du Sac, in Westpoint Township, Columbia County, Wisconsin, as Pitymys pinetorum scalopsoides but cast doubt upon their subspecific identity. He also reported pine mice from Blue Mounds, Dane County, Wisconsin. We have examined these specimens (Westpoint, Columbia County, 2--No. 544, skin only, UWDEZ, and No. 521, skin only, H. C. Hanson's private collection; Westpoint, Dane County, 1, No. 11620, UWZM; Vermont, Dane County, 2, Nos. 11674 and 11694, UWZM) and have compared them with topotypes of P. p. schmidti, and with specimens of P. p. nemoralis and P. p. scalopsoides. The specimens from Columbia and Dane counties differ from P. p. schmidti in the greater zygomatic breadth, and lesser height of skull. They differ from P. p. nemoralis of comparable age in shorter tooth-row and generally smaller skull. The interorbital region, however, is wider. In all of the features mentioned above, the specimens in question agree with Pitymys pinetorum scalopsoides, to which subspecies they are here referred.

Microtus pennsylvanicus aztecus (Allen)

1893. Arvicola (Mynomes) aztecus Allen, Bull. Amer. Mus. Nat. Hist., 5:73, April 28, type from Aztec, 5900 ft., San Juan County, New Mexico.

Allen (loc. cit.) described this species on the basis of two specimens from Aztec, New Mexico, and three from La Plata, New Mexico. He characterized it as "Size large; pelage very full and soft; tail short; skull very narrow.

"Above grayish brown with a tinge of pale buff; fur blackish plumbeous beneath the surface, tipped with pale yellowish brown, and varied with longer, projecting, black-tipped hairs; below grayish white, the fur plumbeous beneath the surface and tipped with white, giving a whitish gray effect. Feet dusky; tail dusky brown above, dull white below."

Allen identified as this species "a large Arvicola from Estes Park, Colorado, which I have before been unable to allocate. I am unable to find that it differs in any particular from the specimens from New Mexico." He pointed out also (op. cit.:73-74) that "The type and only positively identified specimen of Baird's Arvicola modesta [= Microtus pennsylvanicus modestus (Baird)] from Sawatche Pass, Colorado, is a very young specimen in poor condition. An examination of a series of adult and young examples from the type locality will be necessary in order to determine its relationships to A. alticolus [= Microtus longicaudus alticolus (Merriam)] and A. aztecus."

Bailey, in his revision of the American voles of the genus Microtus (N. Amer. Fauna, 17:20), showed Arvicola modesta Baird to be a subspecies of Microtus pennsylvanicus but retained Microtus aztecus (Allen) as a distinct species. In describing M. aztecus he wrote "the size similar to M. pennsylvanicus, but with shorter tail and larger hindfoot; skull long; braincase narrow; interparietal long ..." and remarked that "Microtus aztecus belongs to the pennsylvanicus group. Externally it is not very different from modestus, but none of the specimens show any signs of intergradation; and the skull characters are so well marked that there seems no doubt of its full specific rank."

Subsequent to the publication of Allen's (op. cit.) account and Bailey's account (op. cit.), additional material was collected that helps to clarify the relationships of Microtus aztecus. A comparison of six adult topotypes of Microtus aztecus with a series of nine adults of M. p. modestus from 1 mi. S, 2 mi. E Eagle Nest, 8100 ft., Colfax County, New Mexico, with three adults from 1-1/2 mi. E Manassa, Conejos County, Colorado, and with four adults from Saguache County, Colorado (all in KU), reveals that the supposed "well marked" external and cranial differences between the two forms are not nearly so evident as was indicated by Bailey.

The cranial differences that exist between these two forms (narrower nasals, slightly longer interparietal, slightly longer and narrower skull in aztecus) are evident only as averages. Although geographically intermediate specimens are lacking, the morphological differences between the two kinds of animals are of the degree and kind that separate subspecies, rather than species. We therefore judge M. aztecus (Allen) to be only subspecifically distinct from M. pennsylvanicus modestus and employ the name Microtus pennsylvanicus aztecus.

Microtus pennsylvanicus funebris (Dale)

1940. Microtus pennsylvanicus funebris Dale, Jour. Mamm., 21:338, August 14, type from Coldstream, 1450 ft., 3-1/2 mi. SE Vernon, British Columbia.

Taylor and Shaw (Occas. Papers Charles R. Conner Mus., State College Washington, 2:24, December, 1929) list under Microtus nanus [= montanus] canescens material from Calispell Peak, Washington. Probably the basis for this record is a specimen in the Biological Surveys collection (adult male, 236474) taken on May 9, 1921, by G. G. Cantwell, and labelled as Calispell Peak, 9 mi. W Locke, 3500 ft., Pend Oreille County. An examination (by Hall and Kelson) of the specimen discloses that it is of the species Microtus pennsylvanicus, and that it falls within the geographic range ascribed to the subspecies Microtus pennsylvanicus funebris by Dalquest (Univ. Kansas Publ., Mus. Nat. Hist., 2:346, April 9, 1948).

Microtus oeconomus amakensis (Murie)

1930. Microtus amakensis Murie, Jour. Mamm., 11:74, February 11, type from Amak Island, Bering Sea, Alaska.

When Murie (Jour. Mamm., 11:75, February 11, 1930) named the meadow mouse from Amak Island, Alaska, as amakensis, he arranged it as a separate species. One of us (Hall) and K. R. Kelson examined the type and topotypes of amakensis in the Biological Surveys collection in the U. S. National Museum and compared them with series of Microtus oeconomus operarius, M. o. sitkensis, M. o. elymocetes, M. o. yakutatensis, and M. o. kadiacensis. Among the specimens examined of the latter subspecies were 17 from Izambek Bay, Kodiak Peninsula, on the mainland opposite Amak Island, the type locality of amakensis. The characters given by Murie (op. cit.) serve to separate amakensis from closely related neighboring kinds of meadow mice, but are of the degree and kind that, in this group of meadow mice, separate subspecies rather than species. Although actual intergrades are lacking, the animals from Amak Island are considered to be only subspecifically distinct and to belong to the oeconomus complex. The name Microtus oeconomus amakensis is applied to them.

Microtus longicaudus mordax (Merriam)

1891. Arvicola (Mynomes) mordax Merriam, N. Amer. Fauna, 5:61, July 30, type from Sawtooth (= Alturas) Lake, 7200 ft., east base of Sawtooth Mountains, Blaine County, Idaho.

1938. Microtus longicaudus mordax, Goldman, Jour. Mamm., 19:491, November 14.

Dalquest (Univ. Kansas Publ., Mus. Nat. Hist., 2:353, April 9, 1948) assigned all the meadow mice of the species Microtus longicaudus from approximately the eastern half of Washington State to Microtus longicaudus halli Hayman and Holt and, in doing so, excluded the subspecies Microtus longicaudus mordax from that state. This assignment of specimens in Washington had the effect of separating the geographic range of M. l. mordax into two parts. One part was in south-central British Columbia and the other part was mainly in the Rocky Mountain region of the United States. Hall and Kelson examined specimens in the Biological Surveys collection in the U. S. National Museum in an attempt to determine more precisely the ranges of the subspecies in southern Canada, Washington, and Idaho.

Microtus longicaudus angustus [= M. l. halli] was described by one of us (Hall, Univ. California Publ. Zool., 37:13, April 10, 1931) as differing from mordax in narrower braincase, higher skull near the anterior end of the frontals, darker coloration, and seemingly smaller size. After examining the material in the U. S. National Museum no reason is seen at the present time to amend this characterization, except to add that some specimens of M. l. mordax are as dark as seasonably comparable specimens of M. l. halli.

Examination of specimens of Microtus longicaudus from Washington east of the Cascade Range (those from the Blue Mountain area excepted) discloses that the skulls do not differ essentially from those of topotypes of M. l. mordax, but do differ, as outlined above, from near-topotypes of M. l. halli. There is considerable variation in color among the Washington-taken specimens of Microtus longicaudus. Animals from the eastern flanks of the Cascades average darker than those taken, north of the Snake River, still farther east in Washington. Possibly Dalquest (op. cit.) relied mainly upon this darker color in assigning the specimens from eastern Washington to M. l. halli. Relying principally upon cranial characters, we conclude that most of the specimens are better referred to M. l. mordax and that M. l. halli is restricted, in Washington, to the Blue Mountains.

Specimens examined of Microtus longicaudus mordax.--Total, 74, all in the Biological Surveys Collection, distributed as follows: Washington: Okanogan County: mouth of Holmar Creek, W Fork Paysaten River, 4700 ft., 1; Conconully, 3; Twisp, 1; Omak Lake, 1200 ft., 3. Stevens County: 5 mi. N Colville, 1. Pend Oreille County: 9 mi. N Metalina, 2600 ft., 1; Sullivan Lake, 3000 ft., 3. Chelan County: Sethekin, 1079 ft., 3; head of Lake Chelan, 900 ft., 12; Hart Lake, Railroad Creek, 3900 ft., 1; Entiat, 20 mi from mouth of Entiat River, 1680 ft., 13; Wenatchee, 4. Douglas County: Waterville, 1. Jefferson County: Cleveland, 2. Kittitas County: 2 mi. S Blewett Pass, 3000 ft., 6: Ellensburg, 1500 ft., 4. Whitman County: Colfax, 2. Yakima County: McAllister Meadows, Tieton River, 3000 ft., 3; Gotchen Cr., 5500 ft., near Sava Spring, Mt. Adams, 2. Klickitat County: 8 mi. S Glenwood, base Mt. Adams, 2. Asotin County: Anatone, 3300 ft., 4; Bly, 1000 ft., 2.

Microtus miurus muriei (Nelson)

1931. Microtus muriei Nelson, Jour. Mamm., 12:311, August 24, type from Kutuk River (tributary of Alatna River), Endicott Mts., Alaska.

Rausch (Jour. Washington Acad. Sci., 40:135, April 21, 1950) proposed the name Microtus miurus paneaki, with type locality at Tolugak Lake (lat. 68° 24' N, long. 152° 10' W), Brooks Range, Alaska, for a meadow mouse of the subgenus Stenocranius. This place is only approximately forty miles east and north of the type locality of the earlier named Microtus muriei, also a member of the subgenus Stenocranius. Large series of specimens of this subgenus, from the Arctic Slope of Alaska, are in the Museum of Natural History of the University of Kansas. Study of these indicates that the differences, which Rausch (op. cit.:136) described as distinguishing his M. m. paneaki from M. muriei, result from differences in age of the specimens, and possibly in part from differences in seasonal condition of pelage. For example, Rausch thought that M. m. paneaki was larger than M. muriei but our specimens reveal that such is not the case. The measurements given below of the type specimen of M. muriei (after Nelson, original description) and measurements (in parentheses) of an immature female (43807 K. U.) of Microtus miurus muriei from Chandler Lake, 68° 12', 152° 45', 2900 ft., Alaska, show close correspondence in size. Total length, 119 (122); tail vertebrae, 24 (24); hind foot, 20 (20); condylobasal length, 24.3 (24.5); zygomatic breadth, 10.7 (11.0); greatest width of braincase, 9.0 (9.0); length of nasals, 6.5 (6.0); basal width of rostrum, 4.0 (4.3). In the light of all of the evidence now available, it seems best to treat Microtus miurus paneaki Rausch as a synonym of Microtus muriei Nelson.