Part 84

The average differences in external measurements of the two sexes are: Total length, 83; length of tail, 37; length of hind foot, 11.

Externals.--As described in Mustela frenata goldmani except that hairiness of foot soles is slightly less.

Color.--As described in Mustela frenata goldmani except that: back near (n) Argus Brown or Carbon Brown, tone 3, of Oberthür and Dauthenay, pl. 342; underparts Ochraceous-Buff. Least width of color of underparts, in four specimens, averaging 20 (extremes 18-22) per cent of greatest width of color of upper parts; black tip of tail, in two subadult males, averaging 48 (extremes 46-49) per cent of length of tail-vertebrae.

Skull and teeth.--Male (based on type specimen and subadult no. 132997 from San Vicente): See measurements and plates 25-27, 30; weight 4.4 grams (same for each); basilar length 45.7 (45.3 and 46.1); zygomatic breadth less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; mastoid breadth less than postpalatal length; postorbital breadth more or less than (approximately equal to) length of upper premolars and greater than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; interorbital breadth less than distance between foramen opticum and anterior margin of tympanic bulla; breadth of rostrum not greater than length of tympanic bulla; least width of palate less than length of P4; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 4-1/2 to 5-1/2 upper incisors; height of tympanic bulla less than distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and longer or shorter than rostrum; anterior margin of masseteric fossa below middle of m2.

Female (based on two subadults, nos. 65422 and 218036): See measurements and plates 36-39; weight, 2.4 (2.3-2.5) grams; basilar length, 40.5 (40.4-40.6); zygomatic breadth less than distance between condylar foramen and M1 or than between anterior palatine foramen and anterior margin of tympanic bulla; postorbital breadth more than length of upper premolars or than width of basioccipital measured from medial margin of one foramen lacerum posterior to its opposite; least width of palate more than outside length of P4 and less than inside length of same; anterior margin of tympanic bulla as far posterior to foramen ovale as width of 5 or 6 upper incisors; height of tympanic bulla equal to one-third to one-half distance from its anterior margin to foramen ovale; length of tympanic bulla more than length of lower molar and premolar tooth-row and more or less than (about equal to) length of rostrum.

The skull of the female averages 48 per cent lighter than that of the male.

Comparison of the skull of the male with that of M. f. nicaraguae has been made in the account of that subspecies. The skull of the male as compared with that of M. f. tropicalis has shorter tympanic bullae, deeper braincase at anterior margin of basioccipital, lesser zygomatic and palatal breadth and smaller P4 and m1. The skull of the female is larger in every measurement taken except those reflecting width of the preorbital portion. This part is actually narrower but probably mainly because the females of perda are younger than those of tropicalis. Features in which three skulls of subadults of M. f. perda differ from the five adults of M. f. goldmani and show no overlap are: lesser basilar length, lesser weight, greater relative length of upper tooth-rows, greater relative width of rostrum, greater relative length of rostrum, lesser mastoid and zygomatic breadths, lesser width, length and height of tympanic bullae; lesser outside length of P4 and greater relative depth of braincase at anterior margin of basioccipital and at posterior margin of M1. Features in which perda averages less are: length of tooth-rows, interorbital breadth, orbitonasal length, relative zygomatic breadth, length of m1, outside and inside lengths of P4, width and length of M1, and depth of skull at posterior margin of M1. Features in which perda averages more than goldmani are: relative interorbital breadth, relative mastoid breadth and depth of skull at anterior margin of basioccipital. The length of the inner half of M1 averages the same. As compared with goldmani, the skull of the male of perda is shorter, otherwise generally smaller, but relatively broader except across the zygomatic arches, and relatively deeper. The anterior margins of the tympanic bullae project slightly less from the braincase and the squamosals immediately in front of these bullae are slightly more convex ventrally.

Remarks.--Described by Merriam in 1902 as a subspecies of Putorius tropicalis, the form perda was regarded by Allen (1916:99) as not subspecifically distinct from P. t. tropicalis.

This is the eastern, lowland subspecies of the Tropical Life-zone, corresponding to M. f. goldmani of the higher mountains just as M. f. tropicalis corresponds to M. f. frenata and perotae of the high mountains and table land. The difference in size between perda and nicaraguae and between perda and tropicalis is slight. M. f. perda is slightly less richly colored than M. f. nicaraguae but has the color of the underparts more restricted and has a longer black tip on the tail. In these respects it is second only to M. f. panamensis among Central American weasels. Evidence of intergradation with goldmani is furnished by the specimens from Cobán, Guatemala, and the nearby locality San Cristóbal in Verapaz, Guatemala. Reduced size as compared with goldmani suggests affinity with perda but the greater width of the light-colored underparts, which averages 24 (extremes 18-32) per cent of the greatest width of the color of the upper parts, shows approach to goldmani. Farther north, in Chiapas, however, specimens of perda from San Cristóbal and San Vicente are readily distinguishable from those of goldmani taken a few miles away at Pinabete and near Teopisca. The latter two localities are, however, several thousand feet higher than San Cristóbal (Chiapas) and San Vicente.

Two of the nine skulls (only 3 adult) examined for malformation of the frontal sinuses reveal infestation by parasites.

Specimens examined.--Total number, 18, listed by localities from north to south, and unless otherwise indicated in the United States National Museum.

=Veracruz.= Catemaco, 1.

=Tabasco.= Teapa, 2 (1).

=Chiapas.= San Cristóbal, 1; San Vicente, 1; no locality more definite than state, 1.

=Yucatán.= Chichén-Itzá, 1.

=Guatemala=: Cobán, 2 (1, 1); Finca la Providenci, S. Cristóbal, Verapaz, 3; central Guatemala, 1; no locality more definite than Guatemala, 5 (2).

=Mustela frenata nicaraguae= Allen

Long-tailed Weasel

Plates 1, 25, 26, 27 and 30

Mustela tropicalis nicaraguae Allen, Bull. Amer. Mus. Nat. Hist., 35:100, April 28, 1916.

Putorius tropicalis, Allen, Bull. Amer. Mus. Nat. Hist., 24:661, 1908.

Mustela frenata nicaraguae, Hall, Carnegie Instit. Washington Publ. 473:109, November 20, 1936.

Type.--Male, subadult, skull and skin; no. 30754, Amer. Mus. Nat. Hist., Matagalpa, Nicaragua; April 16, 1910; obtained by W. B. Richardson; original no., 712.

The skull (plates 25-27, 30) of the type specimen lacks the entire right zygomatic arch. Otherwise it is complete. The teeth all are present and unbroken. The skin is complete and unfaded but only partly stuffed.

Range.--Honduras and Nicaragua. Altitudinal and zonal limits unknown. See figure 29 on page 221.

Characters for ready recognition.--Differs from M. f. costaricensis and M. f. goldmani in shorter black tip of tail (not more than 35 per cent of length of tail) and lesser width (usually not more than 7 mm.) of tympanic bulla; from M. f. perda in greater extent of color of underparts (22 or more per cent of greatest width of color of upper parts), shorter black tip on tail (not more than 35 per cent as long as tail) and narrower skull, the mastoid breadth in adult males being less than 23.9 and the zygomatic breadth less than 27.

Description.--Size.--Male: Average and extreme measurements of five subadults and one young (four from Matagalpa and one from San Rafel del Norte) are: Total length, 450 (420-480); length of tail, 178 (150-190); length of hind foot, 48 (46-50). Tail averages 65 (extremes 56-69) per cent as long as head and body. Length of hind foot (measurements from dried skins) more than basal length.

Female: Measurements unrecorded.