The Baculum In The Chipmunks Of Western North America Part 4

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.

_Specimens examined_: 4.

California: _Plumas Co._: Mountains near Quincy, 1 (BS). _Placer Co._: Blue Canyon, 1 (NM). _Alpine Co._: Markleeville, 1 (BS); N fork Stanislaus River, 1 (BS).

#Eutamias speciosus# (Merriam)

Figure 15

General tone of upper parts bright; light and dark elements of color pattern strongly contrasting; outer stripes broad and strikingly conspicuous; size medium; skull moderately broadened; dorsal outline of skull strongly arched in profile; upper incisors short and sharply recurved.

Baculum: Shaft thick; keel of medium height, 1/3 of length of tip; base of keel 1/3 of length of tip; tip 47 to 55 per cent of length of shaft; angle formed by tip and shaft 90; distal 2/3 of shaft markedly compressed laterally; base markedly wider than shaft; shaft short to medium, 2.11 to 3.17 mm.

Differs from _E. panamintinus_, in base of keel proportionally shorter, angle formed by tip and shaft smaller; from _E. umbrinus_ and _E.

palmeri_, in keel higher, angle formed by tip and shaft smaller, distal 2/3 (not 1/2) of shaft markedly laterally compressed, base markedly wider; from _E. bulleri_, in keel smaller, shaft shorter, tip proportionally longer, ridges on either side of tip distinct.

For comparisons with all other species of chipmunks of western North America, see the accounts of those species.

The baculum in _E. speciosus frater_ is approximately the same size as in _E. umbrinus inyoensis_, but differs in shape as described above.

_Specimens examined_: 6.

_E. speciosus frater_: California: _Madera Co._: San Joaquin River, near head of N fork, Sierra Nevada Mountains, 2 (BS).

_E. speciosus sequoiensis_: California: _Tulare Co._: Mount Whitney, 1 (BS); Sequoia National Park, 2 (BS).

_E. speciosus callipeplus_: California: _Kern Co._: Mount Pinos, 1 (BS).

#Eutamias panamintinus# (Merriam)

Figure 16

Dorsal dark stripes reddish; size small to medium; skull of medium size; braincase flattened.

Baculum: Shaft thick; keel low, 1/3 of length of tip; base of keel 1/2 of length of tip; tip 52 per cent of length of shaft; angle formed by tip and shaft 110; distal 2/3 of shaft moderately compressed laterally; base markedly widened; shaft short, 2.17 mm.

Differs from _E. umbrinus_ and _E. palmeri_, in distal 2/3 (rather than 1/2) of shaft moderately compressed laterally; from _E. bulleri_, in keel smaller, shaft shorter, ridges on either side of tip distinct.

For comparisons with other species of chipmunks of western North America, see the accounts of those species.

The structure of the baculum most closely resembles that of _E.

speciosus_ and the geographic ranges of these two species are in juxtaposition.

_Specimen examined_: One from Coal Kilns, Panamint Mountains, Inyo Co., California (CN).

#Eutamias umbrinus# (J. A. Allen)

Figures 17-18

General tone of upper parts dark; size medium to large; skull of medium size; braincase narrowed.

Baculum: Shaft thick; keel low, 1/4 of length of tip; tip 36 to 50 per cent of length of shaft; angle formed by tip and shaft 100; distal 1/2 of shaft markedly compressed laterally; base markedly widened; shaft short to medium, 2.51 to 3.03 mm.

Differs from _E. bulleri_, in shaft shorter, keel smaller, ridges on either side of tip distinct; distal 1/2 of shaft strongly compressed laterally. Does not differ from _E. palmeri_.

For comparisons with all other species of chipmunks of western North America, see the accounts of those species.

Specimens of _E. umbrinus monta.n.u.s_ from north-central Colorado have, in the past (Howell 1929:82), been referred to _E. quadrivittatus quadrivittatus_. In many features these two kinds of chipmunks resemble each other closely; their bacula, nevertheless, differ markedly (compare figs. 8-9 with 17-18).

_Specimens examined_: 25.

_E. umbrinus umbrinus_: Wyoming: _Uinta Co._: 10 mi. S and 1 mi.

W Robertson, 8,700 ft, 1. Utah: _Uintah Co._: Paradise Park, 21 mi. W and 15 mi. N Vernal, 10,050 ft., 12.

_E. u. adsitus_: Utah: _Beaver Co._: Britts Meadow, Beaver Range Mountains, 8,500 ft, 1 (BS). _Wayne Co._: Donkey Lake, Boulder Mountain, 10,000 ft., 1 (UU). _Garfield Co._: Wildcat R. S., Boulder Mountain, 8,700 ft., 1 (UU).

_E. u. sedulus_: Utah: _Garfield Co._: Mount Ellen, Henry Mountains, 1 (BS).

_E. u. inyoensis_: California: _Tulare Co._: Mount Whitney, head of Big Cottonwood Creek, 2 (BS). Nevada: _Elko Co._: W side Ruby Lake, 3 mi. N Elko County Line, 1.

_E. u. nevadensis_: Nevada: _Clark Co._: Sheep Mountains, 1 (MM).

_E. u. fremonti_: Wyoming: _Sublette Co._: 31 mi. N Pinedale, 8,025 ft., 1; 19 mi. W and 2 mi. S Big Piney, 1.

_E. u. monta.n.u.s_: Colorado: _Boulder Co._: 3 mi. S Ward, 9,000 ft., 1; 1/2 mi. E and 3 mi. S Ward, 9,400 ft., 1.

#Eutamias palmeri# Merriam

Figures 17-18