8 16 mi. W, 3 mi. S Piedra, Tamaulipas.
Lasiurus ega
Southern Yellow Bat
Diagnosis.—Upper parts yellowish-brown (much as in Lasiurus intermedius floridanus from Louisiana) having overlay of grayish or blackish anterior to shoulders; hair on basal half of interfemoral membrane more yellowish than elsewhere; size medium (forearm 42.7-52.2; condylocanine length 14.6-16.3).
This species occurs from the southwestern United States (Palm Springs, California, and Tucson, Arizona) southward into Uruguay and northeastern Argentina. Of the six currently (see Handley, 1960) recognized subspecies of L. ega, four occur only in South America, and two occur only in North America.
Cabrera (1958:115) regarded Dasypterus ega fuscatus Thomas (1901:246), based on three specimens from Río Cauquete, Río Cauca, Colombia, as a synonym of Dasypterus ega panamensis Thomas (loc. cit.) that was based on a specimen from Bogava, 250 meters elevation, Chiriquí, Panamá. The latter name has line priority over fuscatus. Cabrera (1958:116) remarked that: "Las diferencias que Thomas señaló entre el Dasypterus de Panamá y el de Colombia (fuscatus) nos parecen estar dentro de los límites de la variación individual, siendo además muy raro que una especie de quiróptero este representada en Colombia y en Panamá por razas diferentes."
On July 16, 1958, at the British Museum of Natural History, one of us (Hall) examined the holotypes of panamensis and fuscatus, as well as other materials used by Thomas, and readily perceived the differences that he pointed out. Thomas' description, although terse, is accurate. L. e. fuscatus is much more blackish than panamensis. We are inclined to retain the two names as applicable to two subspecies. Whether or not fuscatus is synonymized under panamensis, the holotype of panamensis is an intergrade between the almost black Colombian animal (fuscatus) and the paler individuals in Central America and territory north thereof. Even so, the holotype of panamensis more closely resembles the blackish Colombian population than the paler populations to the north and the name panamensis, therefore, is correctly applicable to the bat from Panamá, but not to bats of the species Lasiurus ega from farther north as most authors (see, for example, Hall and Kelson, 1959:194, map 143; and Handley, 1960:474) suggested was the case. For the populations north of Panamá the name Lasiurus ega xanthinus (Thomas) (1897:544) needs to be used.
Lasiurus ega xanthinus (Thomas)
| 1897. | Dasypterus ega xanthinus Thomas, Ann. Mag. Nat. Hist., ser. 6, 20:544, December, type from Sierra Laguna, Baja California. |
| 1953. | Lasiurus ega xanthinus, Dalquest, Louisiana State Univ. Studies, Biol. Ser., 1:61, December 28. |