The limits of the geographic range of tropicalis are fairly well known on the south and west but the only specimen available from the tropical coastal region north of Jico, is a young female from a point 50 miles south of Victoria. Thus, how far north along the coast it ranges toward Matamoros, where M. f. frenata occurs, is not known. The three specimens from Jico, a young female from Jalapa and another adult collected by J. Potts and labeled as coming from México City, are assumed to be typical. The latter specimen certainly came from an elevation lower than that of México City because M. f. frenata occurs there. Although the female from Jalapa, agrees well with specimens from Jico, a male, no. 12764/11058, from Jalapa, has a relatively broader skull, as in perda, although the tympanic bullae are short as in tropicalis. The resemblances to perda in features of coloration are: slightly darker upper parts, and the termination just below the knees of the color of the underparts. There are three specimens labeled as from Orizaba that indicate intergradation with perotae as does also the coloration of the juvenal female from 5 kilometers north of Jalapa. The specimens labeled as from Orizaba are old, poorly-prepared skins, only two of which have partial skulls. The size and coloration of the skins suggest perotae as do also the partial skulls in some respects although the skulls show greater resemblance to those of tropicalis.
The topotype, female, no. 54993, was figured by Merriam (1896, fig. 16, p. 31) along with that of what now is the type specimen of M. f. perotae. Merriam called attention to the great difference in size between the skulls of the two sexes of M. f. tropicalis and compared the condition to that found in noveboracensis. Although the skull of the female from Jico is fully adult, it probably is exceptionally small.
The young female from Xuchil is indistinguishable in coloration from the juvenal female of M. f. perotae from Perote, but in size of skull and size of teeth is intermediate between the female of tropicalis from Jalapa and the females from Cofre de Perote.
There is then, indication of intergradation with M. f. perotae as well as with M. f. perda. M. f. tropicalis differs from M. f. perotae and M. f. frenata in about the same way that M. f. perda differs from M. f. goldmani and M. f. macrophonius. M. f. tropicalis and perda each is smaller and more intensely colored than goldmani and macrophonius, and inhabits the lowland to the east of their highland relative.
At least five of the nine skulls have the frontal sinuses infested by parasites.
Specimens examined.—Total number, 13, all from México, listed by localities from north to south. Unless otherwise indicated specimens are in the collection of the United States National Museum.
Tamaulipas. 50 mi. S Victoria, 1[71]. Near? México City, 1.
Veracruz. Jico, 3; 5 km. N Jalapa, 1[90]; Jalapa, 2 (1[2], 1[75]); Xuchil, 1[60]; Orizaba, 4 (2[75], 1[4]).
Mustela frenata perda (Merriam)
Long-tailed Weasel
Plates [25], [26], [27], [30], [37], [38] and [39]
Putorius tropicalis perdus Merriam, Proc. Biol. Soc. Washington, 15:67, March 22, 1902.
Putorius (Gale) brasiliensis frenatus, Coues, Fur-bearing animals, p. 142, 1877 (part).
Mustela tropicalis perda, Miller, U. S. Nat. Mus. Bull., 79:100, December 31, 1912.
Mustela tropicalis tropicalis, Allen, Bull. Amer. Mus. Nat. Hist., 35:99, April 28, 1916.
Mustela frenata perda, Hall, Carnegie Instit. Washington Publ. 473:109, November 20, 1936.