1942. _Synaptomys cooperi saturatus_ Bole and Moulthrop, Sci.
Publs. Cleveland Mus. Nat. Hist., 5:149, September 11, type from
Bloomington, McLean County, Illinois.
When Bole and Moulthrop named _Synaptomys cooperi saturatus_, with type
locality in Illinois, they, in effect, divided the geographic range of
_Synaptomys cooperi stonei_ into two parts (see A. B. Howell, N. Amer.
Fauna, 50:10 (fig. 2), August 5, 1927) since Bole and Moulthrop (_op.
cit._) did not assign to any subspecies the specimens from southern
Wisconsin that Howell (_op. cit._) had identified as _S. c. stonei_.
Bole and Moulthrop's inclusion in their newly named subspecies of a
specimen from as far west as East Columbia, Missouri, left in doubt the
subspecific identity of specimens from Iowa and a specimen from
Arkansas. Howell (_op. cit._) had assigned this material from Iowa and
Arkansas to _S. c. gossii_.
Howell recognized that the one individual (168266 USBS) from Lake City,
Arkansas, was too young to be identified to subspecies with certainty
and assigned the specimen to _S. c. gossii_ "upon geographical grounds"
(_op. cit._:19). Keith R. Kelson and one of us (Hall) compared this
specimen with pertinent materials. As a result of this comparison we
refer the specimen, on the same grounds employed by Howell, to
_Synaptomys cooperi saturatus_.
Specimens from approximately the southern half of Wisconsin (from Kelly
Lake southward) were referred to _S. c. stonei_ by Howell (_op.
cit._:16). Now that _S. c. saturatus_ has been recognized, these
specimens from southern Wisconsin would be expected to be referable to
_S. c. saturatus_. When these specimens were examined and compared (by
Hall and Kelson) with other specimens in the United States National
Museum the skulls were found to be much larger than in _S. c. cooperi_,
smaller than in _S. c. gossii_, and nearly the size of those of
_Synaptomys cooperi saturatus_, to which subspecies we refer the
specimens in question.
Howell (_op. cit._:16) referred a specimen from Cassopolis, Michigan, a
locality that might be presumed to fall within the range of the more
recently named _S. c. saturatus_, to _S. c. stonei_. Bole and Moulthrop
did not mention this specimen when they described and named _S. c.
saturatus_ (1942). Neither did Burt, but Cassopolis is within the
geographic range ascribed to _S. c. cooperi_ on his map (The Mammals of
Michigan, Univ. Michigan Press, p. 213, 1946). Examination (by Kelson
and Hall) of the specimen (41777 MCZ) reveals that it resembles _S. c.
cooperi_ in shortness of hind foot (18 mm.), shortness of tail (18
mm.), narrowness across zygomata (16 mm.), and grayish pelage. In the
long braincase, heavy rostrum, greater condylobasilar length, greater
lambdoidal breadth, long rostrum, and longer incisive foramina, it
agrees closely with specimens of _S. c. saturatus_, to which subspecies
we refer the specimen.
Necker and Hatfield (Bull. Chicago Acad. Sci., 6:54, 1941) referred
specimens from Rosiclaire, Illinois, to _S. c. gossii_. These specimens
were not mentioned by Bole and Moulthrop (_op. cit._) when they named
_S. c. saturatus_ although the specimens presumably would be referred
to the newly-named subspecies. We have examined the pertinent specimens
(Nos. 15781-15786 and 16049-16054 CNHM) and find that on the basis of
dark color, long and slender skull, heavy incisors, and small
cheek-teeth, they are referable to _S. c. saturatus_ Bole and
Moulthrop. None, however, has a tail so short as the type of _S. c.
saturatus_. For that matter, the average length of the tail of six near
topotypes (5 mi. W, 2-1/2 mi. S Monticello, Piatt County, Illinois,
Nos. 32037-32042 KU) exceeds that of the type (17.4 mm., range 12-20,
as compared to 14 mm. for the type).