1899. _Synaptomys (Mictomys) sphagnicola_ Preble, Proc. Biol. Soc.
Washington, 13:43, May 29, type from Fabyans, Coos County, New
Hampshire.
1927. _Synaptomys borealis sphagnicola_, A. B. Howell, N. Amer.
Fauna, 50:30, August 5.
Howell (N. Amer. Fauna, 50:30-31, August 5, 1927) had only eight
specimens of this subspecies available when he revised the genus
_Synaptomys_. Of these eight (Maine: Mount Katahdin, 2; New Brunswick:
Near Bathurst, 1; New Hampshire: Fabyans, 1, the type; Quebec: St.
Rose, 4), only the type and one of the specimens from St. Rose are
adults. Concerning the others, Howell wrote (_op. cit._:31): "The
example from near Bathurst is not adult and has a damaged skull, so is
identified provisionally. All other specimens are too young for
positive diagnosis."
Since Howell's revision only one additional specimen has been reported.
Anderson (Ann. Rept. Provancher Soc. for 1939, p. 71, 1940) reported it
from Table Mountain, 3888 ft., Gaspe County, Quebec.
In the collection of the University of Kansas Museum of Natural History
there is still another specimen. It is an adult male topotype (No. 6483
KU, formerly No. 72 in the collection of Alfred E. Preble) obtained on
August 21, 1905, at Fabyans, New Hampshire. The measurements of this
specimen are as follows (measurements in parenthesis are those of the
type as given by Howell, _op. cit._): Total length, 135 (132); tail, 26
(24); hind foot, 22 (20); condylobasilar length, 25.1 (25.8); rostral
length, 6.5 (6.8); rostral breadth, 4.7 (4.9); interorbital breadth,
3.3 (2.8); zygomatic breadth, 15.4 (16.0); lambdoidal breadth, 12.1
(12.4); incisive foramina, 5.9 (5.7); height of skull, 9.1 (9.3).
Howell (_op. cit._:30) characterized _S. b. sphagnicola_ as: "Large and
high [skull] with narrow interorbital sharply ridged, the ridges of the
type being joined for a distance of 4 millimeters; interparietal narrow
and rectangular. The rostrum is long, tapering very little, and the
nasals, slightly constricted medially are quite narrow posteriorly. The
incisive foramina are long and wide." Howell further stated (_op.
cit._:30-31) that: "It is hard to predict what will be found to
constitute the most valuable cranial characters in distinguishing this
race from adult _medioximus_. The discernible differences now are in
the shape of the interparietals, rostral characters, and interorbital
differences that will probably not hold good when animals of the same
age are compared."
As can be seen from a comparison of the measurements given above for
the type and the topotype, some of the characteristics given by Howell
are not found in the topotype: The interorbital region is not narrow
(in fact it is wider than it ordinarily is in some other subspecies of
_Synaptomys borealis_) and the incisive foramina are not longer than in
other subspecies of _Synaptomys borealis_.
As far as present material permits us to judge, _Synaptomys borealis
sphagnicola_ is characterized, cranially, by: Skull large; interorbital
region sharply ridged (the ridges being joined for a distance of 4 mm.
in the type and of 4.5 mm. in the topotype); rostrum long, tapering
relatively little; nasals slightly constricted medially and unusually
narrow posteriorly; interparietal narrow and rectangular.