Only one of the three skulls, that of the female, shows evidence of infestation of the frontal sinuses by parasites, and this did not result in malformation of the interorbital region.
Specimens examined.—Total number, 3, all from México, listed by localities from north to south.
Veracruz. Achotal, 1 (Field Mus. Nat. Hist.); Pérez, 2 (U. S. Nat. Mus.).
Mustela frenata tropicalis (Merriam)
Long-tailed Weasel
Plates [25], [26], [27], [30], [37], [38] and [39]
Putorius tropicalis Merriam, N. Amer. Fauna, 11:30, pl. 3, figs. 5, 5a, 6, 6a, text fig. 16, June 30, 1896; Merriam, Proc. Biol. Soc. Washington, 15:68, March 22, 1902.
Putorius frenatus, Merriam, N. Amer. Fauna, 11:27, June 30, 1896.
Mustela tropicalis tropicalis, Miller, U. S. Nat. Mus. Bull., 79:100, December 31, 1912; Allen, Bull. Amer. Mus. Nat. Hist., 35:99, April 28, 1916.
Mustela frenata tropicalis, Hall, Carnegie Instit. Washington Publ. 473:109, November 20, 1936.
Type.—Male, adult, skull and skin; no. 54994, U. S. Nat. Mus., Biol. Surv. Coll.; Jico, Veracruz, México; July 9, 1893; obtained by E. W. Nelson; original no. 5195.
The skull (plates [25]-[27], [30]) is complete. All the upper incisors, except the second and third on the left side, are missing. The right upper canine is broken. The skin is well made and in good condition.
Range.—Up to 5000 feet (as now known) in Tropical Life-zone of Veracruz, México. See figure [29] on page [221].
Characters for ready recognition.—Differs from M. f. frenata and M. f. perotae in least width of color of underparts not exceeding 36 per cent of greatest width of color of upper parts and in postorbital breadth exceeding length of upper molar and premolar tooth-rows; from M. f. macrophonius and M. f. perda in least width of color of underparts averaging more than 29 per cent of greatest width of color of upper parts; and from M. f. perda by longer tympanic bullae which in males are more than 14.9; and from M. f. macrophonius by lesser basilar length (not more than 48) and in postorbital breadth exceeding length of upper molar and premolar tooth-row.
Description.—Size.—Male: The type specimen and no. 12764/11058, a subadult, from Jalapa, Veracruz, measure, respectively, as follows: Total length, 444, 442; length of tail, 175, 160; length of hind foot, 50, 47. The tail is 65 and 57 per cent as long as the head and body. The hind foot is more or less than (approximately equal to) the basilar length.
Female: Merriam (1896:31) gives the measurements of a female topotype (probably no. 54993, U. S. Nat. Mus., which has no measurements written on the attached label) as: Total length, 333; length of tail, 121; length of hind foot, 37. The length of the tail amounts to 57 per cent of the length of the body. The length of the hind foot of no. 54993, U. S. Nat. Mus. is the same as the basal length.
The differences in external measurements between the male and the female topotypes are: Total length, 111; length of tail, 54; length of hind foot, 13.
Externals.—As described in Mustela frenata frenata except that carpal vibrissae do not reach apical pad of fifth digit and hairiness of foot soles is less.
Color.—As described in M. f. frenata except that: Blackish of head extends half way or more from ears to shoulders; upper parts near (14) Brussels Brown or slightly faded tone 2 of Maroon of Oberthür and Dauthenay, pl. 341; underparts of juvenal pelage near (a) Ochraceous-Buff. Least width of color of underparts averaging (in three specimens from Jico and one from Jalapa) 34 (extremes 30-37) per cent of greatest width of color of underparts. Black tip of tail, in two male topotypes, 57.5 (55 and 60) mm. long; thus longer than hind foot and in each individual comprising 34 per cent of length of tail-vertebrae.
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.