PROCEEDINGS

Vol.

XXVI,

pp. 135-138

May

21, 1913

PROCEEDINGS

OF ^IHE

BIOLOGICAL SOCIETY OF WASHINGTON

SIX NEW GROUND SQUIRRELS OF THE CITELLUS MOLLIS GROUP FROM IDAHO, OREGON,

AND NEVADA.

BY

^('.

HART MERRIAM.

An examination

ofthe large scries of

Ground

_Squirrelsofthe mollis

group

^{in the} collection of the

U.

S. Biological

Survey

indicates the existence of halfa

dozen apparently

^well

marked forms which

hitherto

have

escaped recognition.

Unfortunately, must

^of the

specimens were

^{collected in late}

spring

or early

slimmer,

so that the seasonal pelages

can

not be

determined

with certainty. ^{In all} the forms,

however,

^there

appear

^{to be}

two

color

phases —

_gray,

_and

huffy or huffy fulvous.

The _gray

is

commonest

in adults, especially ⁱⁿ early spring; the huffy ⁱⁿ the

young when

first attaining the pelage ^of the adult,

and

in adults in early

summer. _Specimens

in

winter

pelage, collected just before the

animals den up

^{in fall,}

and when _they

first

come

out in spring, are

badly needed.

The new forms may

^be

known from

the following descriptions:

Citellus idahoensis_sp. nov.

Typi from _Payette, at junction ^of Payette ami Snake _River, Idaho.

NO. 168,290 9ad., ^{I'. S.} Nat.

Museum,

^Biol. Survey ^Coll. Collected April 23, 1910, by ^{S. <;.} Jewett. OriginalNo. 17.

Characters.

—

_{Largest of the} mollisgroup. Similarin general ^{to mollis} bul larger,with

much

_{strongertendency} todappling,especially inyoung;

tail longer, broader, and darker; eyelids white; anterior rim of ear usually white. Skull _largeand massive, with outstanding

and outbowed

zygomata.

Color.—

Gray

pelage: pale hoary grayish, faintly suffused with _pale buffy and

more

or less dappled ^on backand _rum]); end of nosedullful- vous, contrasting strongly with grizzled gray ^of top ^ofhead; ^feetsoiled whitish. Buffypelage: very

much

darker throughout and strongly ^suf-

;:;-Pkoc.Biol. Soc.Wash., Vol.XXVI.1913. (135)

136

Proceedings^{of the} Biological Society of

Washington.

fused with pale huffy fulvous; dappling ^of back _very distinct, in

some

cases

amounting

^{almost to} spotting; ^dull fulvous of nose showing^less contrast with top ^of head (which ^{in this} pelage ^is redder); ^tail

much

darker_fulvous, almost ferruginous, with subapical black

band

broad and distinct; ^feetwashed with _buffy.

Young.

— The

_young,

when

firstassuming^theadultpelage, are strongly dappled from behind ^{the shoulders to base of tail.}

The

_pelages of the

young may

^be

known

as_first andsecond.

First coaf.

—

_Pelage long, silky, rather _sparse, buffy-yellowish in color, soon (before the hairs of the second coat appear)

becoming

indistinctly dappled on ^{the back.}

Secondcoat.

— The new

coatcomesin firston the head, ^{a little later}on hinder part^ofback (from middle^ofbackto baseoftail) leaving theneck

and

shoulders covered with the longsilkyhairs of thefirst pelage. This area (anterior half of back) is gradually covered by ^{the second} coat, mainlybythe forward-creeping^oftheline of

new

hairs from themiddle part^oftheback.

The

_dapplingisalwayspronounced

and

isstrongeston the hinder _{part of} the back, very rarely reaching ^{so far}forwardasthe shoulders.

The

second _pelage, which ^is attained

when

the animal is little

more

than half grown, resembles that of the adult. Its general tone

may

^be

eithergrayor buffy-fulvous, usually the ^latter. Of two

young

^collected by^Jewettat

Mountain Home,

Idaho,onthe

same

_day,

May

^{25, 1911, one} (No. 171,329)isgray; the other(No. 171,327) buffy-fulvous.

But

inour large series of

young

^fromseveral localitiesthegray pelage^israre.

Cranial characters.

—

Skull _large, broad

and

massive, with prominent zygomata, large bullae,

and

_heavy teeth.

Compared

^{with mollis (from} type locality, Fairfield, Utah): ^Skull larger

and more

massive; rostrum

and

nasals longer; zygomata

more

spreading throughout; jugal

much

broader

and more

massive; maxillary ^{roots of}zygomata (viewed from ⁱⁿ front) larger, broader,

and more

massive; anterior^frontalregion includ- ing orbital shelf of frontal,

more

elevated; upper(superior) face of pre- maxillary larger and usually reaching farther posteriorly; bullae_larger;

teeth heavier, the toothrow _longer(S.5

mm.).

^{Skulls of adults}varyⁱⁿ the degree^of

bowing

^ofthezygomata.

The

shorterskullshavethe arches stronglyoutbowed; the longer ones have

them much

less prominent.

Measurements.

—

_Averageof8 from_{typelocality:} Total _length, 256; ^tail vertebrae, 62.5; hind _foot, 35.5.

Remarks.

—

Citellus idahoensis inhabits the sagebrush plains of west- central Idaho north of Snake River.

The

Biological Survey has large series of specimens, ^collected mainly by ^S. G. Jewett, from _Payette,

Nampa,

Kuna, Orchard,

and Mountain Home.

Citellus leurodon_sp. nov.

Type from

Murphy,

^{in hillsof}southwestern Idaho westof

Snake

River.

No. 169,031 maleyoung-adult, U. S. Nat.

Museum,

^Biol. SurveyCollec- tion. Collected

May

30, 1910, by^S. G. Jewett. Original No. 112.

Characters.

—

Size rather _large, about equaling idahoensis from the

Merriam —

Six

New

^(Iron

^ml

Squirrels. ^13' opposite ^{side of} Snake _River, bul with shorter tail. Color _gray, nol dappled except ^{in the} young. Teeth very large, equaling

maximum

^oi'

idahoensis Iupper molariform ^series8.5

mm.

).

Cranio^Icharacters.

—

Skull of

medium

size{largerthan mollisami_canus;

slightlysmallerthan idahoensis), strongly ^buill bul slightly ^less massive than idahoensis; zygomata ^not spreadingand not

bowed

outward; ^teeth large, broad and rounded

—

the toothrowequaling the^largest idahoensis

i longer than ^mollis ami therefore

much

longer than canusI.

The

skull and teeth agree most _closely with idahoensis from _Payette, Idaho, hut theskull issmallerand thezygomata^{are less} spreading.

Measurements.

— _Type

_specimen (not _fully adult): Total length, 233;

tail. 47; hind foot. :;.;.

Citellus

canus

vigilis subsp. nov.

Typi from _Vale, eastern Oregon. ^No. 168,361, female_adult, T'. s. Nat.

Museum,

^Biol. Survey ^Coll. Collected April 29, 1910, by^{S. G. Jewett.}

Original No. ^30.

Characters.

—

Similar in general ^to canus; ^coloriron-gray, finely lined,

much

asin_{canus, hut}

more

hoary-whitish. Skull_largeand massive,

much

largerand heavierthan canus

—

infactdecidedly largerthan mollisandnot.

materially smaller than idahoensis;zygomata ^broad and outbowed,

much

asin idahoensis; bullae large, asⁱⁿ mollis

—

_{decidedlylarger} than incanux;

rostrum and nasalslongerthan in canus; toothrow (7.25-7.75) decidedly longer than in conns hut shorterthan in mollis and idahoensis.

Comp&red

with idahoensis from the opposite (eastern) ^{side of}

Snake

River, vigilis ^iseasilydistinguished externallyby ^the absenceofdappling on the back

and

_by shorter and _paler tail;

and

_{cranially, by} smaller bullaeand shortertoothrow.

Measurements.

—

_Average of Sadults from _typelocality ^< _Vale, Oregon):

Total _length, 207; ^tailvertebrae, 36; hind _foot, 30.5. (Type specimen:

208, ^:;:;. 32.)

Remarks.

—

Specimens from ^Paradise Valley, northeastern Nevada, appear^{to he the}

same

as thosefrom Vale

and

Huntington, Oregon.

Citellus mollis

artemesiae

subsp. nov.

Type from ^Birch Creek, Idaho. No.

UUr,

^maleadult,

^U.S.

^Nat.

Museum,

^Biol. Survey^{Coll. Collected} August^'.», L890, by

Vernon

_Bailey.

(Original No. 1573.

Range.

—

_{Sagebrush plains of}southeastern Idaho (north ofthe rangeof mollis; east ofthe range^ofidahoensis).

Characters.

—

Smallest ofthe

known

formsofthemollisgroup. Similar in general to mollis, hut tail grayer, with lessbully fulvous; ^hullae

and

teeth

much

smaller.

Cranialcharacters.

—

Skull _small, smaller and shorter than _{in mollis;}

rostrum rather short and slender; zygomata moderately bowed; ^bullae small

—

as small as in canus; molariform teeth decidedly smaller than in mollis ⁽slightly largerthan in canus).

Compared

^with typical mollis, the rostrum is shorter, the zygomata

more

_bowed, the bullae

much

138

Proceedings of ^the Biological Society of Washington.

smaller. Skull very ^like that of canus but zygomata ^less outstanding anteriorly, braincaseslightly ^less broad posteriorly,

and

toothrow alittle longer; bullae of

same

size.

Measurements.

—

_Average of ^<> specimens from type locality (Birch Creek, Idaho): Total length, L82; tail,37; hindfoot, 29.5. Average ^{of 5} from Blackfoot: _{201, 43.5,}:;'-\

Citellus mollus

pessimus

subsp. nov.

Type from^lower part of Big ^Lost River, east central Idaho. No. _|f| (;

maleadult, ^l

T

. S. Nat.

Museum,

^Biol. Survey ^Coll. Collected July 23, 1890, byC. P. Streator. Original No. ^53.

Characters.

—

Similar to artemesiae (from Birch Creek) but

somewhat

larger

and

darker; tail longer, larger, and_darker; rostrumlarger.

Cranial characters.

—

Skull small like that of artemesiae but longer;

rostrum

and

nasals_longer

and

_broader; tootln-ow longer.

Compared

^with

mollis, skullsmaller; bullae and teeth decidedly smaller.

Measurements.

—

_Average of8from _type locality: Total _length, 205; ^tail vertebrae, 16; hind _foot, 33.

Citellus mollis

washoensis

subsp. nov.

Tiijh from Carson_Valley,westernNevada.

Type

^{No. '',..'',, adult,D.S.}

Nat. .Museum, ^Biol. Survey^{Coll. Collected}

May

^{23, 1889,} by Charles A.

Keeler. Original No. ^34.

Characters.

—

Size large; coloration _grizzled gray throughout, resem- bling canus. Skulllarge, long, and massive

—

_nearly as large as that of idahoensis from _Payette, Idaho, hut narrower, with

more

slender rostrum,

much more

slender premaxillae,

and

shorter toothrow. Similarto mollis, out

more

massive; rostrum and _{palate longer.}

Compared

^{with largest}

skulls of ceinus, therostrum is

much

longer

and more

slender; superior surface of premaxillae

much

slenderer; _j^alate

much

longer; bullae

somewhat

larger; toothrow_{decidedly longer.}

Measurements of type specimen: ^Totallength, 258; ^tailvertebrae, 50;

hind foot,35.