A Synopsis of the American Bats of the Genus Pipistrellus

Excerpt

Four nominal species of the genus Pipistrellus are currently recognized in North America. They are

(F. Cuvier) of eastern North America, (H. Allen) of western North America, (Ward) from Veracruz, Mexico, and Miller from Tabasco, Mexico.

In the past three years, specimens have been obtained in Veracruz (by Dalquest) of each of the southern species. One of these, P. cinnamomeus, previously was known from a single specimen; the other, P. veracrucis, was known only from six specimens which now are lost or misplaced. The results of our study of these recently acquired Mexican specimens constitute our principal contribution in this paper; we have done little more with the material from the United States and Canada than to codify the findings of other mammalogists with respect to the systematic status and geographic distribution.

Study of the available specimens reveals that there are only two species, and ; Pipistrellus veracrucis proves to be only a subspecies (geographic race) of P. subflavus, and Pipistrellus cinnamomeus proves to be a species of another genus, Myotis (see Hall and Dalquest, page 583 of this volume).

 

GenusPipistrellusKaup

1829. Pipistrellus Kaup, Skizzirte Entw.-Gesch. u. naturl. Syst. europ. Thierw., Vol. 1, p. 98, Type, Vespertilio pipistrellus Schreber (not seen by us, after Miller, N. Amer. Fauna, 13:87, 1897).

Range in the New World.—In North America from southern Canada to Honduras (47 degrees to 5 degrees North Latitude) and from the Atlantic to the Pacific; not recorded from the West Indies or South America.

Characters.—Size small; tail approximately as long as outstretched leg; ears well developed with prominent tragus; dental formula: i.; c.; p.; m.; two upper incisors subequal and outer one lacking a concavity on surface facing canine; dentition otherwise essentially as in Myotis Kaup except that third premolar is always, instead of rarely, absent.

Remarks.—There are two species in North America. Their geographic ranges, as now known, meet, but do not overlap. Certain differences between the two species are listed in the parallel columns below. Most of these differences in the skull and teeth are illustrated in figures 22 and 23 on page 92 of Miller's "Revision of the North American bats of the family Vespertilionidae (N. Amer. Fauna, 13, 1897)."

 

StructureColorPredominately grayPredominately brownFootLess than half as long as tibiaMore than half as long as tibiaThumb, length ofLess than 4.9 mm.More than 4.9 mm.TragusBlunt, terminal part bent forwardNarrow, straightSkull (dorsal profile)Nearly straightDish-facedBraincase (viewed from above)SmallLargePalateExtending far behind molars; spine short, narrow at baseExtending short distance long, wide at baseI2UnicuspidateBicuspidateI3Accessory cusp present on anterointernal faceAccessory cusp absent on anterointernal faceP1 (occlusal view)Less than a seventh as large as canineMore than a seventh as large as canineP1 (labial view)Concealed by C1 and P4Not concealedP4Touching canineNot touching caninei3Touching i2 and c1Separated by space from i2 and c1p3Lower than anterior cusp of canineAs high as anterior cusp of canineDistance from c1 to m1Less than length of m2; premolars crowdedMore than length of m2; premolars less crowded

 

Pipistrellus hesperus
(Synonomy under subspecies)

Range.—Arid Sonoran life-zones of western North America from Washington southward to Jalisco....