A new weasel from Costa Rica

Vol.

XXV,

pp. 9-10 January 23, 1912

PROCEEDINGS

OFTHE

BIOLOGICAL SOCIETY OF WASHINGTON

A NEW WEASEL FROM COSTA RICA.

BY

E. A.

GOLDMAN

The

weasel of

Costa Rica has been commonly

^referred

by authors

to Mustela _affinis

Gray,

^of

Colombia, but

ⁱⁿ

making

general

comparisons

ⁱⁿ

connection with

the identification of

specimens from Panama

^I find that

Costa Rican examples

rep- resent a

new form which

is described below.

Mustela

costaricensis _sp. nov.

COSTA RICAN WEASEL.

Type from San Juse,Costa Rica. No.

IHKo

^{J'"1111^ adult, U. S. Na-}

tional

Museum,

^collected by ^{Dr. C.} H.

Van

Patten.

Generalcharacters.

—

_Closelyalliedto_affinis,but

somewhat

larger; color about thesame; audita! bullae relatively larger, ^less flattened. Similar to tropirnlis

and

_perdus, butwhite facial markings reduced ^to narrow streaks, orabsent ⁽broad and conspicuousin tropicalis

and

_perdus).

Color.

— _Upper

_parts, including outer ^{sides of} legs and _feet, blackish

brown

orchestnut, passing gradually^intonearly pure black on neck

and

head; underparts from

median

line of belly to upperpart^of thighs

and

arms_varying from _huffyyellowtoorange buff, palingon throat

and

chin to pure white; white ^facialmarkings absentin type, but_present in

some

specimens, varying from afewisolated hairs toverynarrowwhite streaks across foreheadand cheeks; ^tail like hack, excepttip, whichisblack all round.

Skull.

—

Similarto that of affinis,hut _larger; hraincase

more

_elongated;

audita] bullae relatively larger, less flattened, the anterior borders pro- jecting

more

prominently from cranium. General form

much

asin trop- iralix and perdus, butaudital bulla?flatter.

Measurements.

—

Skull oftype (skinmeasurements notavailable)^: Con- dylobasal length, ">:'>.7; zygomatic breadth, 29; interorbital breadth, 11.7; audital _bulla?, 14.5 x 8; alveolar length ^of upper molariform^tooth- row, ^12.7.

Rirnarks.

— _The

Costa Rican weasel is

somewhat

intermediateinchar- 1—Proc.Biol. Soc.Wash..Vol. XXV,^{1912. (9)}

10 Goldman — _{A New}

_Weasel

_from

Costa Rica.

actersbetween _tropicalis

and

_perdus of southern

Mexico and

_affinis as represented by specimens from^{variouslocalities}from

Panama

southward

and

including a^{series of} 10 from Merida, Venezuela, ^identified by Mr.

Oldfield

Thomas and

assumedtobetypical. ^Itislike_affinisin color,but inthe elongation^ofthe braincase

and

form^ofauditalbullaeseemsto

show

gradationtowardthe bridled weaselsofMexico.

Specimens examined.

—

Total

number.

-5, from Costa Rica, ^{as follows:} San_{Jose (typelocality),} 1_; Navarro, ^1; withoutdefinitelocalities, 3.