قراءة كتاب Comments on the Taxonomy and Geographic Distribution of North American Microtines
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Comments on the Taxonomy and Geographic Distribution of North American Microtines
gapperi we employ the name combination Clethrionomys gapperi phaeus (Swarth). C. g. saturatus, as understood by us, occurs to the southeast of C. g. phaeus in the Rocky Mountains of British Columbia, and in northeastern Washington, northern Idaho and northwestern Montana.
Specimens examined.—Total, 23, distributed as follows: Alaska: Chickamin River (Behm Canal), 15 (MVZ); Boca de Quadra, 3 (MVZ); Marten Arm, Boca de Quadra, 1 (USNM); Quadra Lake, 1 (USNM). British Columbia: Fort [= Port] Simpson, 3 (USBS).
Clethrionomys gapperi wrangeli (Bailey)
1897. Evotomys wrangeli Bailey, Proc. Biol. Soc. Washington, 11:120, May 13, type from Wrangell, Wrangell Island, Alaska.
When Bailey (loc. cit.) named the red-backed mouse from Wrangell Island, Alaska, he characterized it as "A large, dull-colored species entirely distinct from any known form," and remarked: "In no way does E. [= Clethrionomys] wrangeli show a close relationship to any other American species. In size and relative proportions it comes closest to E. dawsoni, from which it differs widely in coloration and more widely in cranial characters. With the long-tailed species south and east of its range there is no need of comparison."
Swarth (Univ. California Publ. Zool., 24:173, June 17, 1922) reported that three specimens from Flood Glacier and 23 from Great Glacier, British Columbia, and four from Sergief Island, at the mouth of the Stikine River, Alaska, were: "All E. wrangeli, indistinguishable from specimens at hand from Wrangell Island." Swarth further reported that, although he found no intergradation between Clethrionomys wrangeli from Flood Glacier and the nearly adjacent Clethrionomys rutilus dawsoni, "the two species, however, resemble each other so closely in form, and in some pelages in color also, that wrangeli would seem to be a coastal offshoot of dawsoni...."
Davis (The Recent Mammals of Idaho, The Caxton Printers, p. 306, April 5, 1939) and Orr (Jour. Mamm., 26:69, February 12, 1945) more recently have shown that Clethrionomys wrangeli is not a member of the rutilus group (to which C. dawsoni belongs) but is a member of the gapperi group.
Our comparisons of a series of eight topotypes of wrangeli (all in the Biological Surveys Collection) with several subspecies of Clethrionomys gapperi (including phaeus, saturatus, galei, brevicaudus, and others) reveal that the differences seen in wrangeli are of the kind and degree that serve to separate subspecies. The red-backed mouse from Wrangell Island, then, should stand as Clethrionomys gapperi wrangeli (Bailey).
Specimens examined.—Total, 31, distributed as follows: Alaska: Wrangell, Wrangell Island, 27 (19 MVZ., 8 USBS); Sergief Island at mouth of Stikine River, 4 (MVZ).
Clethrionomys gapperi solus, new subspecies
Type.—Male, adult, skin and skull, No. 74939, Biological Surveys Collection, United States National Museum; from Loring, Revillagigedo Island, Alaska; obtained on September 22, 1895, by C. P. Streator; original No. 4980.
Range.—Known only from two localities on Revillagigedo Island, Alaska.
Diagnosis.—A short-tailed, dark-colored member of the gapperi group. Dorsal stripe wide, between Chestnut and Bay (capitalized color terms after Ridgway: Color Standards and Color Nomenclature. Washington, D. C., 1912), with slight mixture of black-tipped hairs; sides and venter heavily washed with Ochraceous-Tawny. Skull flattened; rostrum proportionately short and wide; auditory bullae relatively uninflated.
Comparisons.—From topotypes of Clethrionomys gapperi wrangeli, C. g. solus differs as follows: dorsal stripe wider and slightly brighter; sides brighter; venter more heavily washed with Ochraceous-Tawny (heavy wash in all 13 C. g. solus examined; in C. g. wrangeli no wash in 11, slight wash in 16, and heavy wash in only one); nasals, alveolar extent of upper cheek-teeth and incisive foramina shorter; skull shallower when measured with tympanic bullae included; rostrum averages slightly broader.
From C. g. phaeus of the adjacent mainland, C. g. solus differs in: dorsal stripe slightly darker; ventral wash more prominent; tail shorter; skull smaller in all parts measured except that nasals are approximately the same length, auditory bullae notably smaller and teeth notably narrower.
Measurements.—External and cranial measurements of adults are shown in table 1.
Remarks.—Bailey (Proc. Biol. Soc. Washington, 11:120, May 13, 1897) referred 17 specimens from Loring to his newly named species, E. wrangeli [= Clethrionomys gapperi wrangeli] but based his description on specimens from Wrangell Island. He pointed out (loc. cit.) that all of the specimens from Loring had the "bellies strongly washed with buffy-ochraceous, while more than half of those from Wrangell have whitish bellies."
Specimens examined.—Total, 13, all in the Biological Surveys Collection, U. S. National Museum, from the following localities: Alaska: Revillagigedo Island: Loring, 10; mouth of Fish Creek, Ketchikan, 3.
Clethrionomys gapperi stikinensis, new subspecies
Type.—Male, adult, skin and skull, No. 30735, Museum of Vertebrate Zoology, University of California; from Stikine River at Great Glacier, British Columbia; obtained on August 13, 1919, by J. Dixon; original number 7691.
Range.—Known only from the lower Stikine River Valley of British Columbia and the Cleveland Peninsula of Alaska.
Diagnosis.—A medium-sized, dark-colored member of the gapperi group. Dorsal stripe wide, near Auburn with mixture of black-tipped hairs; sides and venter washed with Ochraceous-Tawny. Skull small; cheek-teeth narrow; auditory bullae relatively uninflated.
Comparisons.—From topotypes of Clethrionomys gapperi wrangeli, C. g. stikinensis differs as follows: dorsal stripe slightly wider and brighter; sides slightly duller (lacking the olivaceous wash of C. g. wrangeli); all cranial measurements taken averaging smaller except height of skull, which is approximately the same; alveolar length of upper tooth-row and length of incisive foramina notably shorter; auditory bullae less inflated; cheek-teeth much narrower.
From topotypes of C. g. phaeus, C. g. stikinensis differs as follows: dorsal stripe and sides darker; auditory bullae less inflated; cheek-teeth narrower; skull smaller in most measurements taken (see table 1).
From topotypes of C. g. solus, C. g. stikinensis differs as follows: dorsal stripe lighter (more tawny underwash); ventral wash of buffy much paler (especially noticeable around mouth and on throat); zygomatic and lambdoidal breadths greater; skull deeper; auditory bullae more inflated; cheek-teeth slightly heavier.
Table 1. External and cranial measurements of Clethrionomys.
| Number of individuals averaged of each sex or specimen measured |
Total length |
Tail | Hind foot |
Condy- lobasilar length |
Zygomatic breadth |
Lambdoidal breadth |
Length of nasals |
Alveolar length of upper tooth- row |
Breadth of rostrum |
Length of incisive foramina |