PROCEEDINGS

Vol. XIX, ^pp. 87-90

PROCEEDINGS

OF THE

BIOLOGICAL SOCIETY OF WASHINGTON

luJ

IDENTITY OF EUTAMIAS PALLWUS _(ALLP]N), WITH

A DESCRIPTION OF A RELATED FORM FROM THE SOUTH DAKOTA BAD LANDS.

BY MERRITT GARY.

A

careful

study

^{of the}

chipmunks commonly known

as

Eu-

tamias minimi(s in the collection of the Biological

Survey and

the Li. S.

National ]Museum has brought

to light

some

interest-

ing

^{facts in}

regard

^{to their} interrelations

and

distribution.

The above

material^isrichin

specimens from northern Wyoming ^and

southern Montana, and proves

conclusively that

Tamlas _quad-

rivittatus pallidas

Allen

isa valid _species.

A

related

form from South Dakota Bad Lands

^is described as

new.

Eutamias

_{pallidus (Allen).}

Tamiaft quadrivlttatus palUdus Allen, Proc.Bost. Soc.Nat. _Hist.,

XVI,

p.

289, 1874.

7'nmiasminimus_Allen,Bull.

Am.

Mus.Nat.Hist., Ill,p.110,1890(part)—

not ofBacliman,^1839.

General characters.

—

Similar in coloration to E. minimus, but

much

larger; hind footabout33

mm.

_(insteadof₃₀₎; tailnearly 100

mm.

Color.—

A

specimen from

Camp

Thorne,

Montana

_(No.11,656,U.S.N. M., July 18, 1873), agrees very ^{well in color} with early August examples^of minimus from

Green

River.

Comparable chipmunks

(fresh postbreeding pelage) from other localities intheYellowstone_region (Powderville, ^Al- zada,

and

Painted

Robe

_Creek) havethesides

more

_heavily

washed

with ochraceous.

Cranialcitararlers.

—

Skull_relatively

much

_larger

and

heavierthanin

E.

minimus, thezygomata

more

abiuptly spreading^; anterior jwrtion of nasals broad; auditalbullae_larger

and more

inflated.

Measuremeids.

— A

_verylargefemalefrom Painted

Robe

_Creek,

Montana

:

Total_length,220; tail vertebrae, 104; hind_foot,34.

Two

males fromthe

same

locality,not_fullyadult: 204; 92; 32;

and

205; 94; 33; respectively.

A

specimen from

Powder

River_Basin,

Wyoming,

^222; 106; ^34.

The

hind 19—Pkoc. Biol. Soc.Wash.,Vol. X1X,:1906. (S7)

88 Gary —

Identitjfof

Eutamias

_{jxdlidus iAllen).}

footof the

Camp Thome

specimen (relaxed from dryskin) measures32, a millimeter less than the averaj^e. Average ^{of fonr adult} males of E.

viiniiiins from Green River,

Wyoming:

^Total length, 188 _(180-195j; tail vertebrae 87 (80-92); hind_{foot, 30.}

The

skullof the_largefemalefromPainted

Robe

_Creek,Montana, meas- ures^: Ocdpito-nasallength,343; basilarlength of Hensel,^26.5; zygomatic breadth,^19.1; greatestbreadth of braincase,16.8. Anotherskull fromthe

same

_localitymeasures: 32.1 ; 24.4; ^18.-t; 1(3.5.

A

large skull from

Powder

River _Basin, Wyoining: ^32.9; 24.8; 18.2; ^IG.5. Average^of four skulls of ndnimus from Green River^: Occipito-nasal length, 30.3; basilarlength of Hensel,^23.1; zygomaticbreadth,17; greatestbreadthof braincase, ^15.4.

Rf'indrks.

— _Chipmunks

fromthe following^localities agree^wellwith the

CampThorne

specimen,* assumed^tobe_typical:

—

Moulinia: Painted

Robe

Creek, Sage Creek (Big

Horn

_{Basin), .\lzada,} Powderville. Wi/omivg:

Pt)wder River Basin, Merino, Moorcroft, Thornton, Newcastle, Douglas, Big

Horn

Basin.

Chipmunks

^fromFort

Washakie and Wind

River Basin average

somewhat

_{smaller,but agree} incoloration; wiiileothersfromthe Pine Ridge country^ofnorthwestern Nebraska

(Warbonnet Canyon and

Glen, Sioux County, ^Coll. Univ. of Nebr.) are intermediate in colora- tion between _typical E. pitlUdns

and

_{the pale}

Bad

Lands form which ^is describedlater in the presentpapei'. Tiie

much

larger size

and

longer^tail of_pnllidusserveatoncetodistinguish ^itfromthe small iitiiiiiiii(.'<. Inter- gradation cannot be

shown

from present material and with such a dis- crepancy^{in size it}seems best to givepal/ldHfi full specific rank. Green River_City,

Wyoming,

^hasbeen conmionlyaccepted ^asthe typelocalityof

ml)iin)V!i,-fbutTownsend'sNarrative_J seemsto place^itconsiderably north of that_j)oint,

and

notfarfromthe

mouth

ofBig

Sandy

^Creek.

In the _original description of E. pallidiiii (1.c). DoctorAllen gave ^its habitatas "

The

Great_Plains,

and

the desert region generally of the^inte- rior of the continent." In a footnote it is characterized as ^"

The

small, paleformof the high,dryplainsof theinterior."

No

type specimen'was designated,norwas _{a typelocalityassigned.} In alaterpaper,^ however, DoctorAllengave^a

more

detailed characterization,

and

remarked_(p.796) tlvAtpnUidus

"

Reaches

anextreme

_phaseofspecialization intheYellowstone regionin respect toboth _pallor

and

smallness ofsize.

He

still further re- stricted pallidus totheYellowstone_region

by

the followingwords_{(p. 800):}

"typical paUiddH (from theYellowstone Plains)."

Among

^thespecimens listed

by

^{DoctorAllenwerethreetaken}

by

^himselfat

Camp

Thorne,Yel- lowstoneRiver,July18,1873. Thesearethe onlyspecimens from^adefinite locality in theYellowstone regionwhich

he

considered "verypale." As oneoftheabove specimens ^(No.11,656,U.S.N. M.) ^{is still}extant,andina good^stateof preservation,^itseemsbest toconsider

Camp ^Thorne

the type locality.

*Thesiteof

Camp

^Tlionicisnear the presenttownofGlendive,Montana.

tCf. Allen, Bull.Am.Mus. Niit.Hist., Ill, p. 112,IS'.tO.

XNarr.Journeyacross Roclcy Mts.,etc.,p.71,^183'J.

\Mou.jN.Am.llodeu,p. 795, 1877.

Cary —

Identity of

Eutamias

_ixdlidusiAllen).

89 Eutamias

pallidus

cacodemus

subsp. nov.

BAD LANDS CHIPMUNK.

Tamias minimus _Allen, Bull.

Am.

Mus. Nat. Hist., Ill, p. 110, 1890 _(in part,specimen from

"

MauvaisesTerres_").

Type from Sheep Mountain, Big

Bad

Lands, South Dakota. No._138,137, U.S.National

Museum,

BiologicalSurveyCollection, d* adult. Collected September2,1905,

by

^Mei-rittCary. Original number,^682.

Geiurul characters.—Size, a triflelarger than_pallidus; coloration

much

paler^{; tail}verylong.

Cranial c/mrf»dtTS.— Skull similarto that of_pallidus, but _{slightly larger}

and

heavier.

Color.— Breeding pelage

(May and

June):

Median

dorsal_stripeblackish, witha_slightadmixtureof ochraceous; lateral stripespaleochraceous_buff, with an olivaceous_tinge. Dorsal _pairof light stripes creamgray,^lateral pairwhite. Facial stripespale huffy ochraceous. Ears_pale,lacking ochra- ceous of^fall specimens. Forehead_gray. Sides

and

back_{of neck,}sidesof

body and

flanks grayish white, with a^traceofbuff. Feet

and rump

grayish white, underparts pure^white. Undei' surface oftail cream _color,with a narrowblacksubmarginal

band

; sidehairstipped with white. Hairs

on

upper^{surfiiceoftail} broadly white_{at base,}then

banded

with _black,

and

apically white,producing^a

mixed

black

and

whiteeffect.

A June

male from Corral

Draw

(No.fHf, ^Coll.

Am.

Mus. Nat. _Hist.,

June

9, 1894,

W. W.

_Granger)^is

commencing

^to

assume

thefresh

autumn

coatonhead

and

shoulders; while theback

and rump

present theextreme phase^of

worn

winter_pelage,being faded

and

bleacheduntilthe_stripesare scarcely discernible. Fre.^Ji posdjreedivg pelage (August

and

September):

Median

dorsal _stripe dark

tawny

ochraceous,

becoming

^{blackish toward}

rump

^; lateral stripes

tawny

ochraceous. Dorsal_pairoflight stripesgrayish white; ^lateral pair broader, pure white.

Dark

facial stripes ochraceous, weakJy ^{indicated in} palest examples. ^Anterior portion of ears bright ochraceous. Forehead

mixed

_gray

and

ochraceous,^or plain gray. Post- auricularspots large

and

white. Sides

and

back of neck (except dorsal stripe),sidesof body,

and

flanks

washed

with

creamy

^buff,ora very pale ochraceous in darkest individuals. Uitper^surfaces of feet grayish white to

creamy

^white.

Under

surface oftail varying fromclay^{color to}cream

buft',theblack submarginal

band

narrow. Hairs

on

upper^{surfaceoftail} basally

and

_apicallycreambuff",the

median

zoneblack.

Comparable

specimens ^{of E.} pallidus in poslbreeding pelage havethe sides

more

strongly ochraceous, the dorsal

and

lateral stripes

much

darker,

and

theundersurface oftailochraceous.

Measurements.

—

_Average of four adult males from type locality^: Total length,^216.5 (210-225)^{; tail}vertebrae,^103.3 (97-110); hind_{foot,34.5 (34-}

35). Type: ^Totallength,210; ^tailvertebrae, 100; hind_{foot, 34.} Average cranial measurements^: Occipito-nasal length, ^{32.5; basilar} length of Hensel,24.9; zygomatic breadth, ^18.4; greatest breadthof _braincase, 16.

Type:

32.3; 24.4; 17.6; ^15.6.

Specimens examined.

—

Totalnumber,32,^allfrom South Dakota,^asfollows:

90 Cary —

Identity of

Eutamlas pallidm

^(Allen).

Corral

Draw

(nearSheep Mountain) ^{12(Coll. Au).}Mus. Nat._{Hist., VV.}

W.

Granger)^;

Cheyenne

^River

Bad Lands

12,

and

^"MauvaisesTorres^"_{1 (Coll.}

U. S. Nat. MuH., ^L. Stejneger

and

F. V.

Hayden,

respectively)^; Sheep

Mountain

7 (Biol.Surv.Coll.,Merritt Cary).

Remarks.—

^{iiofaras at}present

known,

^{this beautiful}

chipmunk,

^whichis

by

^{far the}palest

member

of the genus, occurs onlyⁱⁿ theBig

Bad Lands

ofwesternSouth Dakota,

and

the

Hat

Creek Basin

Bad Lands

of extreme northwestern

Nebraska*—

theMxiivdises Tears ofthe French voyageurs.

The

extreme_pallorof coloration ismanifestly dueto environment.

The

white, alkaline soil, which _supports scarcely a_vestigeof vegetation over large areas, exerts a strong bleaching ^effect

upon

^{the few}

mammals

re- stricted to the

Bad

Lands.

The

most

marked

instance of this

among mammals,

^asidefrom chipmunks, ^isNeoloum rwpkolu, thepalestwood-rat,

which

occurs only

among

^the

^Bad

^Lands.

*While colU'ctiiifi in tlic IliitCreek Basin in ]'.)01, tlicwriter often saw _verypale chipmunks^iutheBad Landsoflliatregion,but unfortunately^eolleetedno specimens.