FREE BOOKS

Author's List




PREV.   NEXT  
|<   3   4   5   6   7   8   9   10   11   12   13   14   15   16   17   18   19   20   21   22   23   24   25   26   >>  
bserved that the name _Eutamias_, proposed by Trouessart in 1880 as a subgenus of _Tamias_ is here adopted as a full genus. This is because of the conviction that the superficial resemblance between the two groups is accidental parallelism, in no way indicative of affinity. In fact the two groups, if my notion of their relationship is correct, had different ancestors, _Tamias_ being an offshoot of the ground-squirrels of the subgenus _Ictidomys_ of Allen, and _Eutamias_ of the subgenus _Ammospermophilus_, Merriam." Howell (1929:23) proposed _Neotamias_ as the subgeneric name for the chipmunks of western North America, of the genus _Eutamias_. Ellerman (1940, 1:426) gave _Eutamias_ and _Neotamias_ equal subgeneric rank with _Tamias_ under the genus _Tamias_; on pages 427-428 he quoted Merriam, as I have done above, and later, after quoting the key to the genera and subgenera of chipmunks of Howell (1929:11), Ellerman wrote (_op. cit._: 428-429), "This key convinces me that all these forms must be referred to one genus only. The characters given to separate '_Eutamias_' from _Tamias_ are based only on the absence or presence of the functionless premolar, and on the colour pattern. If colour pattern is to be used as a generic character, it seems _Citellus suslicus_ will require a new name when compared with _C. citellus_, etc." And again, "The Asiatic chipmunk is intermediate between typical _Tamias_ and the small American forms in many characters." To substantiate this, Ellerman (_loc. cit._) quotes Howell (_loc. cit._), in comparing the subgenera _Eutamias_ and _Neotamias_, as follows: "'the ears [of subgenus _Eutamias_] are broad, rounded, of medium height, much as in _Tamias_; postorbital broad at base, tapering to a point, much as in _Tamias_; interorbital constriction slight, as in _Tamias_; upper molariform tooth rows slightly convergent posteriorly, as in _Tamias_.'" Ellerman (_loc. cit._) again quotes Howell (_loc. cit._), "'_Eutamias_ of Asia resembles _Tamias_ of North America and differs from American _Eutamias_ in a number of characters, notably the shape of the anteorbital foramen, the postorbital process, the breadth of the interorbital region, the development of the lambdoidal crest, and the shape of the external ears. On the other hand, American _Eutamias_ agrees with the Asiatic members of the genus in the shape of the rostrum, the well-defined striations of the upper incisors, the presence of the extra
PREV.   NEXT  
|<   3   4   5   6   7   8   9   10   11   12   13   14   15   16   17   18   19   20   21   22   23   24   25   26   >>  



Top keywords:

Tamias

 

Eutamias

 

Howell

 

Ellerman

 

subgenus

 

Neotamias

 

American

 
characters
 

postorbital

 

chipmunks


interorbital

 

pattern

 

Merriam

 

America

 

colour

 

Asiatic

 
quotes
 

presence

 

subgenera

 

subgeneric


proposed

 

groups

 

citellus

 

compared

 

agrees

 

intermediate

 
typical
 

chipmunk

 

incisors

 

Citellus


character

 

generic

 

suslicus

 

striations

 

rostrum

 

members

 

require

 

defined

 
external
 

tapering


resembles
 
differs
 

number

 
posteriorly
 

molariform

 
constriction
 

slightly

 

convergent

 

notably

 

anteorbital