Part 83

As compared with M. f. frenata: White facial markings slightly less extensive; blackish (not black) of head extending onto neck; upper parts slightly darker; ventral side of tail noticeably darker; color of underparts more restricted, averaging approximately one-third rather than nearly one-half width color of upper parts; black tip of tail one-third rather than one-fourth length of tail and much longer than hind foot. Similar differences of lesser amount exist between perotae and tropicalis. M. f. perda, macrophonius and goldmani bear the opposite relation to tropicalis. That is to say, in the latter: White facial markings slightly more extensive; blackish of head less extended over neck; upper parts markedly lighter; color of underparts less restricted and black tip of tail shorter.

Skull and teeth.--Male (based on type specimen and a subadult, no. 11058, from Jalapa): See measurements and plates 25-27, 30. As described in Mustela frenata perda except that: Weight 4.7 (4.6 and 4.7) grams; basilar length 46.7 (45.5 and 47.8); zygomatic breadth more or less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; least width of palate more than length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 4 (including I3) upper incisors; anterior margin of masseteric fossa below middle of m2 or posterior to that tooth.

Female (based on no. 54993 and no. 1060): See measurements and plates 37-39. As described in Mustela frenata perda except that: Weight (of 54993) 2.2 grams; basilar length, 37.5 (36.0-39.0); zygomatic breadth more or less than distance between anterior palatine foramen and anterior margin of tympanic bulla; least width of palate more than greatest length of P4; height of tympanic bulla equal to one-third to three-fourths of distance from its anterior margin to foramen ovale.

The skull of the adult female is 53 per cent lighter than that of the type specimen, a male.

Comparison of the skulls of males and females with those of M. f. perda, the nearest relative, has been made in the discussion of that subspecies. Some of the features that readily distinguish skulls of M. f. tropicalis from those of M. f. frenata, perotae and macrophonius are as follows: Weight less than 4.8 grams; basilar length less than 48; postorbital breadth more than length of upper M-Pm tooth-row. The skulls of male frenata, perotae and macrophonius are much larger, heavier, and are decidedly more angular with more constricted postorbital region the least width of which is less than the length of the upper premolars. In frenata the anterior margins of the tympanic bullae are protruded much farther from the braincase. The skull of the female of M. f. tropicalis is smaller, weighing less than 3 grams; basilar length less than 41; postorbital breadth more than length of upper molar and premolar tooth-row.

Remarks.--This subspecies was originally described by Merriam as a full species. Later he described Putorius tropicalis perdus as another subspecies. Allen (1916) placed P. t. perdus in synonymy but named Mustela tropicalis nicaraguae as new. In the present paper all three forms are recognized but are regarded as only subspecifically distinct from the other bridled weasels of México and Central America.

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. Near? México City, 1.

=Veracruz.= Jico, 3; 5 km. N Jalapa, 1; Jalapa, 2 (1, 1); Xuchil, 1; Orizaba, 4 (2, 1).

=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.

Type.--Male, subadult, skull and skin; no. 100041, U. S. Nat. Mus., Biol. Surv. Coll.; Teapa, Tabasco, México; March 31, 1900; obtained by E. W. Nelson and E. A. Goldman; original no., 14074.

The skull (plates 25-27, 30) is unbroken and all the teeth are present and entire. The skin is well made and in good condition.

Range.--Fifty feet (Chichén Itzá) to 4000 feet (San Vicente) in Lower Tropical Life-zone south from southern Veracruz through southern México into Guatemala. See figure 29 on page 221.

Characters for ready recognition.--Differs from M. f. nicaraguae in lesser extent of color of underparts (not more than 22 per cent of greatest extent of color of upper parts), black tip of tail more than 38 per cent of length of tail, and broader skull (in adult males, mastoid breadth more than 23.9 and zygomatic breadth more than 27.4); from M. f. tropicalis in more restricted color of underparts (least width of color of underparts less than 28 per cent of greatest width of color of upper parts) and shorter tympanic bullae, which in males are less than 15; from M. f. goldmani by total length not exceeding 489, least width of color of underparts not exceeding 24 per cent of greatest width of color of upper parts, weight of adult skull less than 5 grams and basilar length less than 48.5.

Description.--Size.--Male: The type specimen and another subadult from San Vicente, Chiapas, measure, respectively, as follows: Total length, 473 and 443; length of tail, 184 and 169; length of hind foot, 51 and 51.5. The tail is 62 and 64 per cent as long as the head and body. The length of the hind foot is greater than the basal length.

Female: Estimates made from the dried skin of no. 218036 are: Total length, 375; length of tail, 140; length of hind foot, 40. The hind foot of no. 65422 from Catemaco also measures 40.