by smaller average size, see measurements; from _M. f. longicauda_
by near (14 _n_ to _l_) Brussels Brown rather than near (_h_) Clay
Color of the upper parts, and in males by a shallower occiput in
which the depth of the skull, exclusive of the sagittal crest, and
taken at the anterior border of the basioccipital, amounts to
less than 59 per cent of the mastoid breadth; from _M. f. alleni_
by near (14 _n_ to _l_) Brussels Brown rather than near (_h_) Clay
Color of upper parts in summer; from _M. f. neomexicana_ by near
(14 _n_ to _l_) Brussels Brown rather than Buckthorn Brown color
of upper parts, in absence of white frontal spot continuous with
color of underparts, in basilar length of less than 46 in males
and 40 in females; from _M. f. arizonensis_ by total length
averaging more than 375 in males and 330 in females, basilar
length averaging more than 41 in males and 36.7 in females; from
_M. f. inyoensis_ by absence of white facial markings; from _M. f.
pulchra_ by absence of light facial markings, near (14 _n_ to _l_)
Brussels Brown rather than near (16 _j_) Buckthorn Brown color of
upper parts, and lesser size, hind foot less than 40 in females
and basilar length averaging less than 46.0 in males; from _M. f.
xanthogenys_ by absence of light facial markings and near (14 _n_
to _l_) Brussels Brown rather than Buckthorn Brown color of upper
parts; from _M. f. munda_ by absence of white facial markings,
presence of color of underparts on ventral face of proximal third
of tail, and hind foot of less than 50 in males; from _M. f.
saturata_ by presence of light color of underparts on tail and
ankle and in lesser average breadth across mastoid processes of
skull (see measurements); from _M. f. oregonensis_ by absence of
nasofrontal white patch, presence of light color of underparts on
ventral face of tail, and shorter skull, which, relative to its
length in males, is deeper through the braincase; from _M. f.
washingtoni_ by presence of light color of underparts on ventral
face of tail, by skull which in male relative to basilar length is
shorter in the preorbital region and wider across the zygomata and
mastoid processes, and in female has longer preorbital region and
larger bullae (see measurements); from _M. f. altifrontalis_ by
lighter colored upper parts which are tones 1 to 3 of Raw Umber,
pl. 301, rather than tone 4 of Brownish Drab, pl. 302, of Oberthür
and Dauthenay, by Buff-Yellow to Straw Yellow rather than near
(14´ _a_ to 16´ _c_) Ochraceous-Buff color of underparts, by least
width of color of underparts amounting to more than 37 per cent of
greatest width of color of upper parts, by presence of color of
underparts on ventral side of tail and on hind leg over ankle, and
by lesser depth of skull through frontal region; from _M. f.
effera_ by larger size, males averaging 12-1/2 per cent larger in
external measurements, 8 per cent larger in linear measurements of
skull, and 22 per cent heavier in weight of skull, total length
averaging 400 rather than 360, basilar length averaging 43.6
rather than 40.5.
_Description._--_Size._--Male: Twenty-one adults from the southern
half of the Sierra Nevada of California yield average and extreme
measurements as follows: Total length, 400 (356-428); length of
tail, 150 (125-178); length of hind foot, 46.1 (42-50). Tail
averages 60 per cent as long as head and body. Length of hind foot
averaging more than basal length. Corresponding measurements of
twelve adults from extreme southern and southwestern Colorado are
as follows: 407 (355-431); 150 (133-170); 46.0 (42-49).
Female: Ten adults from the Sierra Nevada of California yield
average and extreme measurements as follows: Total length, 349
(336-362); length of tail, 127 (120-133); length of hind foot,
36.3 (32-39). Tail averages 57 per cent as long as head and body.
Length of hind foot less than basal length. Corresponding
measurements of ten adults from the Rocky Mountains of central
Colorado are as follows: 347 (325-375); 123 (111-141); 40
(32-43).
The average differences in external measurements of the two sexes,
in the Sierras of California are: Total length, 51; length of
tail, 23; length of hind foot, 9.8. Weight of 7 adult males from
California is 267 (226-345) grams. Two adult females from there
weigh 148 and 115 grams and 3 from White Pine County, Nevada, 134,
122 and 124, giving an average of 129 grams.
_Externals._--Longest facial vibrissae black, brown or white
(often all three colors in same specimen) and extending beyond
ear; carpal vibrissae same color as underparts and extending to
apical pad of fifth digit; hairiness of foot-soles (in summer
pelage) about as shown in figure 19.
_Color._--Upper parts, in summer, near (14 _n_ to _l_) Brussels
Brown or tones 1 to 3 of Raw Umber of Oberthür and Dauthenay, pl.
301, darker on top of head from nose to line connecting posterior
margins of ears. Chin and upper lips white. Remainder of
underparts Buff-Yellow to Straw Yellow and sometimes
Ochraceous-Buff especially in young, and in some adults from
southern Colorado. In winter, all white, except tip of tail, or
upper parts near (_j_) Snuff Brown or lighter than Brussels Brown
with a smoked effect, and underparts white. Tip of tail at all
times black. Color of underparts extends distally on posterior
sides of forelegs over toes onto antipalmar faces of feet and
wrists, on medial sides of hind legs to ankles, over antiplantar
faces of toes, medial third of tarsus and usually over proximal
tenth to three-fourths of ventral side of tail. Least width of
color of underparts averaging, in a series of twenty males from
the southern half of the Sierra Nevada of California, 59 (37-76)
per cent of greatest width of color of upper parts. In seven males
from southern Colorado corresponding percentages are 55 (37-71).
Black tip of tail in series from Sierra Nevada averaging 50
(40-60) mm. long; thus longer than hind foot and averaging 33-1/3
per cent of length of tail-vertebrae.
_Skull and teeth._--Male (based on 25 adults, from Sierra Nevada
of California): See measurements and plates 19-21; weight, 3.7
(2.9-4.9) grams; basilar length, 43.6 (40.6-46.1); zygomatic
breadth more than distance between condylar foramen and M1 (save
in four instances) and more than distance between anterior
palatine foramen and anterior margin of tympanic bulla (save in
two specimens); mastoid breadth more (80 per cent of specimens) or
less (20 per cent) than postpalatal length; postorbital breadth
less than length of upper premolars and more or less than width of
basioccipital measured from medial margin of one foramen lacerum
posterior to its opposite; interorbital breadth more or less than
distance between foramen opticum and anterior margin of tympanic
bulla; breadth of rostrum less than length of tympanic bulla;
least width of palate less than medial length of P4 (except in two
specimens); anterior margin of tympanic bulla as far posterior to
foramen ovale as width of 3 to 5 upper incisors; height of
tympanic bulla more than distance from its anterior margin to
foramen ovale; length of tympanic bulla more than length of lower
molar and premolar tooth-row and longer or shorter than rostrum;
anterior margin of masseteric fossa not carried farther forward
than point directly below hypoconid of m1.
Female (based on ten adults from Sierra Nevada of California): See
measurements and plates 33-35; weight, 2.2 (1.8-2.4) grams;
basilar length, 38.2 (36.7-39.5); zygomatic breadth more (except
in one specimen) than distance between condylar foramen and M1 and
more (save in two specimens) than distance between anterior
palatine foramen and anterior margin of tympanic bulla;
postorbital breadth less than length of upper premolars and less
than (except in one specimen) width of basioccipital measured from
medial margin of one foramen lacerum posterior to its opposite;
least width of palate more or less than either outside or inside
length of P4 but generally less than inside length; tympanic bulla
as far posterior to foramen ovale as width of 3 to 5-1/2 upper
incisors; height of tympanic bulla more or less (usually more)
than distance from its anterior margin to foramen ovale; length of
tympanic bulla more than length of lower molar and premolar
tooth-row and more or less than length of rostrum.
The skull of the female averages 41 per cent lighter than that of
the average male.
Compared with the skull of _M. f. longicauda_, that of both sexes
averages smaller in every measurement taken. Males of _nevadensis_, on
the average, relative to the basilar length, are narrower in the
interorbital region and across the zygomata but have the orbitonasal
length greater. Stated in another way, the rostrum of _longicauda_
appears to be shorter and broader and the zygomata are more expanded.
Females of _nevadensis_, on the average, relative to the basilar length
are narrower across the mastoid processes and zygomata and have the
braincase deeper at the anterior margin of the basioccipital. Also in
_nevadensis_ the mastoid processes do not project so far laterally
beyond the braincase, the lambdoidal crest and postorbital processes
are less well developed and except in the interparietal region, the
temporal ridges hardly meet and they form a sagittal furrow rather than
a low sagittal crest which characterizes adult females of _longicauda_.
Each of these differences separating the females of _longicauda_ from
those of _nevadensis_ are of the same nature, although not necessarily
of the same degree, as those which appear in _longicauda_ with
increasing age. The differences mentioned above are readily appreciable
when series of specimens are compared. However, none of the differences
is of great degree, and most parts of the skulls of the two subspecies
are of similar relative proportions. Even so, there is but little
overlap in actual size. Comparisons with the skulls of _M. f.
oribasus_, _alleni_, _neomexicana_, _arizonensis_, _inyoensis_,
_pulchra_, _xanthogenys_, _munda_, _saturata_, _oregonensis_,
_washingtoni_, _altifrontalis_, and _effera_ are made in the accounts
of those subspecies.
_Remarks._--The populations to which the name _nevadensis_ at present
is assigned have gone by the name _arizonensis_ since Mearns proposed
this name in 1891. Before that time Coues (1877:141) had included
individuals of this race under the name _Putorius longicauda_.
Among the populations here assigned to _M. f. nevadensis_, there is
some geographic variation but it is of lesser degree than in most other
species of mammals which range over the same region. Comparison of 20
adult males from the Rocky Mountains of Colorado with 25 adult males
from a place as far distant as the Sierra Nevada of California shows
that the two populations closely resemble each other. The specimens
from Colorado average a trifle wider across the zygomata, have a longer
body and therefore relatively shorter tail, and, except in southern
Colorado, a slightly longer hind foot. Comparison of ten adult females
from each of the two areas reveals that those from Colorado have a
markedly longer hind foot, and a tail somewhat shorter relative to the
length of the body. The mentioned differences are the only ones found
among the great number of points investigated, except that as remarked
by Merriam (1896:23) the Sierran animal has the yellow of the
underparts reaching farther up under the chin, the underside of the
tail on the average is more suffused with yellowish and the white on
the upper lip is more extensive. As regards the last mentioned feature,
my check of 34 skins from Colorado reveals that the white extends all
the way around the upper lip in every specimen but one, whereas in 69
specimens from the Sierra Nevada the white extends all the way around
the upper lip in only 39. However, as further remarked by Merriam
(_loc. cit._), not only this but the other color features are
inconstant in addition to being slight. When the occurrence of the dark
spots near the angles of the mouth are tabulated, it is found that in
33 Colorado-taken specimens they are absent in 19, faintly indicated in
13, and well developed in 1. In 62 California-taken specimens they are
absent in 37, faintly indicated in 20, and well developed in 5.
In northwestern Colorado, southern Wyoming, and possibly through the
Bear River Divide into southeastern Idaho, long-tailed weasels here
referred to _nevadensis_ approach _longicauda_ in large size and
occasionally in other features, more closely than do specimens of
_nevadensis_ from most other places in its range. This tendency is
thought to be significant for much of the area in question lies in or
below the Transition Life-zone, the same life zones in which farther to
the eastward true _longicauda_ occurs.
One specimen that illustrates this approach to _longicauda_ is an adult
male, no. 2334, collection of E. R. Warren, from 6160 feet, Lay, Routt
[now Moffat] County, Colorado. In large size and, relative to the
basilar length, shorter rostrum and shorter tympanic bullae, it agrees
with _longicauda_ but the darker color and, relative to the basilar
length, narrowness of the rostrum, interorbital region, zygomatic
expanse and the shallowness through the region of the postorbital
processes place it with _nevadensis_. Of two other specimens from
Steamboat Springs, Routt County, a young male, no. 4010, in the
collection of E. R. Warren, has a hind foot (50 mm.) as long as in
_longicauda_; and the other, no. 138195, U. S. Nat. Mus., an adult
male, agrees well enough in size and proportions with _nevadensis_ but
has the coloration typical of _longicauda_.
From Wyoming, one subadult female, no. 177553, U. S. Nat. Mus., from
Garrett, is intermediate in size and coloration but is nearer to
_nevadensis_ in these particulars, as it is in all other points
considered except size of the molar teeth which are as large as in
_longicauda_ and larger than in any female _nevadensis_ from Colorado
or California. Another female, an adult, no. 179304, U. S. Nat. Mus.,
from Lonetree, Wyoming, agrees with _longicauda_ in size of skull.
Indeed, ten of seventeen cranial measurements exceed the maximum for
Colorado-taken _nevadensis_. Where differences exist in relative
proportions of the skull as expressed in percentages of the basilar
length, the specimen approaches _nevadensis_ in 5 instances and
_longicauda_ in only 3. The color is intermediate but much nearer that
of _nevadensis_ with which the animal agrees also in external
measurements. Ten subadults (5 of each sex) from within 12 miles of
Laramie (not Fort Laramie) show greater resemblance to _nevadensis_ but
definitely approach _longicauda_. Average external measurements are:
[M], 408, 155, 44; [F], 361, 134, 40. The two other specimens examined
from this general locality, a young female, no. 2711, Mus. Vert. Zoöl.,
from Fort Bridger, and a subadult female, no. 188377, U. S. Nat. Mus.,
from Bridger Pass, show no departures from _nevadensis_ of similar age.
The specimens from scattered localities in the Transition Life-zone of
northwestern Colorado and southern Wyoming are larger than _nevadensis_
is elsewhere, and also in certain other features resemble _longicauda_
of the plains to the eastward. Everything considered, the animals in
question are much more like _nevadensis_ than _longicauda_. Study of
more specimens, especially from Wyoming, might provide grounds for
recognizing as a different subspecies the animals in this large area
comprising parts of Colorado and Wyoming from which so few specimens
now are available. Possibly the name _Putorius culbertsoni_ Coues would
apply. Decision on that point will require adequate material from the
type locality, Fort Laramie. See discussion of this name under _M. f.
longicauda_.
In southeastern Idaho males are larger than they are at most other
places within the range of _nevadensis_. An average of 7 adults and
subadults from Pegram, Montpelier, Springfield, and the vicinity of
Pocatello, reveals, when compared with the average of _nevadensis_ from
Colorado and that of _longicauda_ from the Great Plains, that this
population from southeastern Idaho is nearest to _longicauda_ in linear
measurements of the orbitonasal length, mastoid breadth, length of
tympanic bullae, and as expressed in percentage of the basilar length,
length of tooth-row, breadth of rostrum, and zygomatic breadth. In all
other points of size, relative proportions and color, the animals
approach nearer to, or actually agree with, _nevadensis_.
The specimens commented upon clearly show intergradation between
_nevadensis_ and _longicauda_. Similarly, the specimens from
Scottsbluff County, Nebraska, here referred to _M. f. alleni_, by their
larger size suggest intergradation of that subspecies with the larger
_nevadensis-longicauda_ stock although the approach is more toward
_longicauda_ than _nevadensis_. Between _oribasus_ and _nevadensis_,
however, there is no lack of material showing intergradation. As set
forth in the account of _oribasus_, specimens from Montana are truly
intermediate structurally as well as geographically.
Intergradation with _washingtoni_ is shown by specimens from the
northern part of the Cascade Range in Chelan and Okanogan counties,
Washington. The adult male, U. S. Nat. Mus., no. 235183, from Bald
Mountain, is referable to _washingtoni_ on the basis of cranial
characters but all the other adult and subadult specimens examined from
Chelan and Okanogan counties are nearer _nevadensis_ on the basis of
cranial characters. Indeed, some show no approach to _washingtoni_ in
cranial characters. As might be expected on geographic grounds, the
specimen from Easton, U. S. Nat. Mus., male subadult, no. 116870, shows
approach to _washingtoni_. This is true of the coloration of the hind
limbs, small size of the tympanic bullae, and relatively greater length
of the preorbital part of the skull. However, the greater width of the
light color of the underparts and relatively great breadth across the
mastoid processes and zygomatic arches are points of agreement with
_nevadensis_. Similarly, a series of 7 specimens from the Entait River,
20 miles above its mouth, in tone of color is nearer to _washingtoni_,
as is one of the two skulls of adult males in length of the preorbital
region. However, in greater breadth of the skull otherwise, and in the
relatively great width of the light color of the underparts, the
animals are nearer to _nevadensis_, to which they are here referred.
Some of these characters mentioned above in which departure is shown
from typical _nevadensis_ are characters that show approach to
_altifrontalis_. This is especially true of the more intense coloration
and restriction of the color of the underparts.
Complete intergradation with _effera_ is shown by specimens from
southern Oregon. The change from small _effera_ to the larger
_nevadensis_ here is gradual; consequently in northeastern California
and southern Oregon the size increases gradually to the northward.
Specimens showing complete intergradation with _oregonensis_ and
_saturata_ are wanting. However, one specimen from Crescent Lake
suggests _oregonensis_ in having near (18) apricot yellow underparts
such as occur frequently in _oregonensis_. Also some specimens from
northern California approach _saturata_ in having the color of the
underparts reduced in the extent to which it reaches out on the under
side of the tail. This fact and the consideration that the two races
are less different from one another than are other kinds which
definitely are known to intergrade leave no doubt but that material
from the intervening localities would show complete intergradation.
Intergradation between _nevadensis_ and _munda_ is indicated by
specimens from South Yolla Bolly Mountain, Trinity County, which are
commented on at greater length in the account of _M. f. munda_. _M. f.
inyoensis_ is so closely related to _nevadensis_ as to leave no doubt
that specimens from suitable localities will show actual
intergradation. That intergradation occurs directly with the bridled
weasel of the interior valleys of California, _M. f. xanthogenys_, is
shown by specimens from along the west-facing flank of the southern
part of the Sierra Nevada. Probably intergradation occurs all along the
Sierra Nevada on the western slope but specimens are lacking to show
this. Weasels are known to occur in the foothill territory and the
lesser attention given to this region by mammal collectors than to the
higher parts of the mountains may explain the lack of preserved
specimens. Individual specimens, here referred to _nevadensis_, but,
showing varying degrees of approach to _xanthogenys_ are as follows: A
female from Hume; a male and a female from 8000 feet elevation, Monache
Meadows; a male from 9800 feet elevation on the east fork of the Kaweah
River; and 7 specimens, probably one family, from one-half mile south
of Mineral King, 7850 feet. Of the specimens from 7850 feet, the adult
male has no light facial markings and the head is only slightly darker
than the back. The adult female has much restricted, light facial
markings and the intervening areas are darker than in the male. The
five juveniles trapped in the same burrow as the female, each has more
extensive light facial markings than the adult female although the area
of this varies from only slightly more than in the female to as much as
in typical specimens of _xanthogenys_. Also, the dark color of the head
in these five specimens averages darker than in _nevadensis_ and more
as in weasels to the southwestward especially _latirostra_. One of the
five juveniles is lighter colored over all of the upper parts than
_nevadensis_ and is suggestive of _xanthogenys_ in this respect.
Finally, the adult male has on the underparts small spots of ochraceous
orange suggestive of _latirostra_ and some individuals of _pulchra_.
No. 30655/42628, U. S. Nat. Mus., taken on Mount Whitney, also shows
white facial markings and some other features of the valley-inhabiting
_xanthogenys_. A suggestion of intergradation with _arizonensis_ is
furnished by specimens, referred to that race, from Springerville and
the Kaibab Plateau. No specimens happen to be available from the region
in which intergradation would be expected between _nevadensis_ and
_neomexicana_. Since _neomexicana_ and _arizonensis_ intergrade it is
probable that _nevadensis_ also will be found to intergrade with
_neomexicana_. In summary, _nevadensis_ is judged to intergrade with
each of the subspecies of _Mustela frenata_ whose range adjoins that of
_nevadensis_.
This subspecies is remarkably free from injury to the frontal sinuses
such as result from the presence of parasites. In 98 adults from
Oregon, California, Nevada, and Colorado, no malformation was noted.
Only 1 of the 26 specimens from Washington was malformed and it was an
intergrade with _washingtoni_. The single adult from New Mexico was
diseased, as were 3 of the 6 from British Columbia, 1 of the 20 from
Idaho, and 1 of the 7 from Utah.
_Specimens examined._--Total number, 568, arranged alphabetically
by provinces and states and from north to south by counties in
each state. Unless otherwise indicated specimens are in the
collection of the United States National Museum.
=Arizona.= _Apache County_: 15 mi. E Luka Chu Kai Navajo School,
8000 ft., 2.
=British Columbia.= Monte Cr., 20 mi. E Kamloops, 1[21]; Sicamous,
2; Okanagan, 18 (7[2], 6[85], 1[75], 1[86]); Monashee Pass, 1[31];
Swan Lake, near Okanagan Landing, 1[22]; Okanagan Landing, 11
(2[74], 3[31], 3[86], 3[22]); Vernon, 1[74]; Hope-Princeton
Summit, 5600 ft., 1[77]; Hope, 1[20]; Similkameen, 1[77];
Osoyoos-Bridesville Summit, 1[77]; Anarchist Mt., Osoyoos, 1[31];
Myer's Creek, 1[77]; Rossland, Mt. Glory, 7000 ft, 1[77]; Cascade,
1[77]; Nelson, 1.