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قراءة كتاب The Baculum in the Chipmunks of Western North America
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shorter, tip proportionally longer, angle formed by tip and shaft smaller, distal 2/5 of shaft more laterally compressed; from E. quadrimaculatus in, keel proportionally higher, angle formed by tip and shaft larger, tip proportionally longer, distal 2/5 of shaft more laterally compressed, shaft shorter; from E. speciosus, E. panamintinus, E. umbrinus, E. palmeri, and E. bulleri, in base not markedly widened, shaft usually longer.
For comparisons with E. alpinus, E. minimus, E. townsendii, E. sonomae, E. amoenus, E. dorsalis, E. merriami, and E. quadrivittatus, see the accounts of those species.
The differences between the bacula of the subspecies Eutamias ruficaudus ruficaudus and E. r. simulans are comparable to those usually found between species of chipmunks. Consequently, I suspect that E. r. simulans and E. r. ruficaudus are specifically distinct and suggest that a search would be worth while for specimens in the geographic area between the geographic ranges as now known for the two kinds to ascertain whether intergradation (the criterion of subspecies) occurs. I suppose there is no intergradation but in the absence of precise information, I choose not to modify the current taxonomic arrangement of E. r. ruficaudus and E. r. simulans.
Specimens examined: 17.
E. ruficaudus ruficaudus: Montana: Flathead Co.: 1 mi. W and 2 mi. S Summit, 5,000 ft., 2. Ravalli Co.: Big Hole Hill, 6,000 ft., 2; Big Hole Hill, 6,600 ft., 1; Continental Divide, Big Hole Hill, 7,000 ft., 1.
E. r. simulans: Idaho: Bonner Co.: Priest Lake, 1 (BS). Kootenai Co.: 13 mi. E and 5 mi. N Coeur d'Alene, 3. Shoshone Co.: Mullan, 1 (BS). Clearwater Co.: 25 mi. E and 16 mi. N Pierce, 6.
Eutamias cinereicollis (J. A. Allen)
Figure 13
General tone of upper parts dark grayish tawny; size medium to large; skull large; braincase widened.
Baculum: Shaft thick; keel proportionally low, 1/5 of length of tip; tip 34 per cent of length of shaft; angle formed by tip and shaft 145°; distal 1/3 of shaft slightly compressed laterally; base slightly widened; shaft long, 4.88 mm.
Differs from E. quadrimaculatus, in keel lower, ridges on either side of tip weakly developed, angle formed by tip and shaft larger; from E. speciosus, E. panamintinus, E. umbrinus, E. palmeri, and E. bulleri, in shaft longer, base not markedly widened, angle formed by tip and shaft much larger.
For comparisons with E. alpinus, E. minimus, E. townsendii, E. sonomae, E. amoenus, E. dorsalis, E. merriami, E. quadrivittatus, and E. ruficaudus, see the accounts of those species.
Specimen examined: One from Mount Thomas, White Mountains, Apache Co., Arizona (BS).
Eutamias quadrimaculatus (Gray)
Figure 14
General tone of upper parts bright reddish; pattern inconspicuous; light and dark facial stripes strongly contrasting; size large; skull relatively small and slightly built.
Baculum: Shaft thick; keel relatively low, 1/4 of length of tip; tip 27 per cent of length of shaft; angle formed by tip and shaft 120°; distal 1/3 of shaft slightly compressed laterally; base slightly wider than shaft; shaft long, 4.35 to 5.28 mm.
Differs from E. speciosus, E. panamintinus, E. townsendii, E. umbrinus, E. palmeri, and E. bulleri, in shaft markedly longer; base not markedly widened; angle formed by tip and shaft larger; tip proportionally shorter.
For comparisons with all other species of chipmunks from western North America, see the accounts of those species.