MUSTELA AFRICANADesmarest

Tropical Weasel

(Synonymy under subspecies)

Type.—Mustela africanaDesmarest, Nouv. Dict. d'Hist. Nat., vol. 19, p. 376. 1818.Range.—Known from the headwaters of the Amazon in eastern Perú and from near the mouth of the same river, on its southern side in Brazil, all within the Tropical Life-zone. See figure29on page221.

Type.—Mustela africanaDesmarest, Nouv. Dict. d'Hist. Nat., vol. 19, p. 376. 1818.

Range.—Known from the headwaters of the Amazon in eastern Perú and from near the mouth of the same river, on its southern side in Brazil, all within the Tropical Life-zone. See figure29on page221.

Characters for ready recognition.—Differs fromMustela frenata, the only geographically adjacent species of the genus, by: presence of thenar pad on forefoot; presence of a longitudinal, median, abdominal stripe of same color as upper parts; upper lips being broadly edged, entirely round, with color of underparts; failure of longest facial vibrissae to reach posterior margin of ear; absence of p2; relative flatness (see pl. 29, fig. i and pl. 39, fig.h) of tympanic bullae.

Characters of the species.—Size large (total length of adults approximately 500 mm.); foot-soles naked; thenar pad present on forefoot; length of claws, measured on concave sides, less than one and one-fourth times depth of claws measured at bases; longest facial vibrissae not reaching posterior margin of ear; tail relatively long haired; tail at all ages terminating in point as is characteristic of only juveniles and very young ofMustela frenataandM. erminea; tip of tail, and muzzle, only slightly darker than remainder of upper parts; upper lips broadly edged with color of underparts; pelage coarse, harsh and sparse; longitudinal, median, abdominal stripe of same color as upper parts present; skull broad and deep; braincase large, rounded, and much inflated anteriorly; palatal region wide; tympanic bullae less inflated than in any other American species of the subgenus; angle of lower jaw reduced; dental formula

3 1 2-3 1-, -, ---, -;3 1 2 2

teeth heavy; medial lobe of M1 but slightly larger than lateral lobe. See plates28,29,30,39and cranial measurements.

Geographic variation.—The reddish versus chocolate color of the upper parts constitutes the only variation of a geographic nature so far detected.

Remarks.—One of the most noteworthy of the several unique characters of this large, tropical weasel is the longitudinal, median, abdominal band. The species exhibits the minimum degree of development of certain features that become progressively less apparent as one proceeds southward from Central America. The relative uniformity of the coloration of the upper parts (reduction in intensity of black color on the muzzle and tip of the tail) and the reduction of the tympanic bullae are two cases in point. Viewed dorsally the general outline of the skull is most nearly matched by that of the skull ofMustela frenata meridanafrom Venezuela or that ofM. f. hellerifrom Perú. However, the resemblance is not close. The tympanic bullae, although unique among American weasels, are more like those ofM. f. meridanafrom Venezuela than like those of any other kind. The great postorbital width (relatively less inM. africanathan in several South American subspecies ofMustela frenata) and small angular process of the mandible are characters, in varying degrees, also common to all South American weasels. StructurallyM. africanaclearly is more nearly like other subspecies ofM. frenatafrom South America than it is like any species or subspecies from North America.

Mustela africanais the most primitive of the American weasels. The distinctive cranial and dental characters, excepting the reduction in number of premolars, are of a primitive nature. For example, the relatively wide postorbital region, the large braincase that is inflated anteriorly, and the flattened, tympanic bullae, are points of resemblance to the holarcticMustela erminea, which species is regarded as nearest the original stem form; also the mentioned characters correspond to ontogenetic stages passed through by other weasels. Mostly on these accounts, one is led to look uponM. africanaas a migrant from North America. It may have become isolated from its original stock, by a water barrier in the Central American region, for a length of time sufficient to permit of a degree of differentiation to develop between it and the North American weasels which prevented crossbreeding with thefrenatastock when that stock, at a later time, reached South America. This assumption is suggested only by evidence from the Recent specimens. No remains of true weasels (subgenusMustela) have been recorded from deposits in South America older than the Recent period. The alternate possibility, thatM. africanaintergrades with some race ofM. frenatain western or northern South America, has been considered and regarded as highly improbable.

Cabrera (1940:15) has made the distinctive structural characters ofMustela africanabasis of the generic nameGrammogaleto include the one speciesafricana. I am inclined to accordGrammogaleonly subgeneric rank.

It is possibly significant thatMustela africanais intermediate in several respects betweenLyncodonand typicalMustela. The median, longitudinal, abdominal band of the same color as the upper parts inM. africanaand the relative uniformity of the coloration of its upper parts might be considered as an intermediate stage between the dark, bicolored (black muzzle and tail tip and brown body) upper parts and light-colored underparts of the North American weasels on the one hand and the light, unicolored upper parts and dark-colored underparts of the Patagonian weasel (Lyncodon) on the other hand. The number of premolars,

2-3---,2

is also intermediate between the numbers

3 2- and -3 2

of the North AmericanMustelaand the PatagonianLyncodon, respectively. The AmericanMustelaand the PatagonianLyncodon, respectively. The more medially, as opposed to anteriorly, directed medial cusp of P4 (characteristic of approximately half of the specimens examined), and the structure of the skull in general ofM. africanaalso seem to be morphologically intermediate between those parts ofMustelaandLyncodon.

On the chance thatLyncodonis closely enough related toMustela, to be included in a group withMustelarather than in a group withGrisonella, it is worth noting thatLyncodon lujanensisAmeghino (1889:324, 325), from the villa of Lujan and at the city of Córdoba, at each place in the Pampean [= Pleistocene] formation of Argentine (see also Cabrera, 1928:263) is the first and only fossil form of this group recorded from the whole of South America. Actually, however,Lyncodonseems to me to be as nearly related toGrisonella, if not more so, than toMustela. IfLyncodonis more closely related toGrisonellaandGrisonthan toMustela, then the above remarked intermediacy in characters ofM. africanahas more of interest as a tendency to parallelism than it has of phylogenetic import. Appraisal of phylogenetic relationships would require appraisal of the ancestral stem forms of theGrisonstock and theMustelastock. None of either is known from deposits of the Pliocene, the period of time immediately preceding the Pleistocene.

None of the skulls ofMustela africanaseen or figured has the nasomaxillary sutures entirely obliterated and the specimens would, judged on this character alone and by analogy with North American species, be regarded as young and subadult. However, the sutures close at what seems to be a later age than inM. frenataandM. erminea. The condition of the mammae in the type specimen ofM. stolzmanniand in the specimen from Moyobamba, indicate that they have borne young. North American weasels old enough to bear young lack visible traces of the nasomaxillary sutures. I have examined no skulls ofafricanawith greatly worn teeth and hence cannot say if the sutures are obliterated in advanced age.

If available data be correct, this species is unique within the genus in that the two sexes are of approximately the same actual size and of the same relative proportions in the body and in the skull. There was no difference between individuals said to be of different sexes from Pará, described and figured by Goeldi (1904:61-62, pls. 1, 2). The undoubted female, type specimen ofMustela africana stolzmanni, is as large as the undoubted male, no. 37475, of the same species, but of a different subspecies, from Pará, Brazil. All the specimens ofM. a. africanathat I have handled are labeled male and those ofM. a. stolzmannifemale. More material may show that the female is smaller than the male, as is the case in all near relatives ofM. africana.

Little has been recorded concerning the habits of this species. Tate (1931:254) states that a live individual which he saw in a cage at Pará had been captured "swimming in the salt water of the estuary about half a mile away from the shore." On the label of the specimen from Moyobamba, there appears: "caught in Willow tree."

Subspecies examined.—All described forms, of which there are two.

Tropical Weasel

Plates28,29,30and41

Mustela africanaDesmarest, Nouv. Diction. d'Hist. Nat., 19:376, 1818; Cabrera, Bol. Real Soc. Españ. de Hist. Nat., 13:429, November, 1913; Cabrera, Bol. Real Soc. Españ. de Hist. Nat., 14:175, pl. 1, March, 1914.Putorius (Mustela) brasiliensis paraensis, Goeldi, Zool. Jahrb. abt. f. systematik, geogr. u., Biol., 10:556, pl. 21, September 15, 1897, type from Pará, Brazil, near Pará, Ward of Marco da Legoa, Brazil; Goeldi, Bol. do Mus. Paraense, 3:195 [translation of orig. descr.], August, 1901.Putorius paraensis, Goeldi, Bol. do Museu Goeldi, 4:61, pls. 1, 2, 1904.Mustela affinis paraensis, Hollister, Proc. Biol. Soc. Washington, 28:143, July 10, 1914.Mustela paraensis, Allen, Bull. Amer. Mus. Nat. Hist., 35:105, April 28, 1916; Tate, Journ. Mamm., 12:253, August 24, 1931.Mustela stolzmanni paraensis, Hall, Carnegie Instit. Washington Publ. 473:111, November 20, 1936; Hall, Physis, 16:167, pl. 1, figs. 1-4, 1939.

Putorius (Mustela) brasiliensis paraensis, Goeldi, Zool. Jahrb. abt. f. systematik, geogr. u., Biol., 10:556, pl. 21, September 15, 1897, type from Pará, Brazil, near Pará, Ward of Marco da Legoa, Brazil; Goeldi, Bol. do Mus. Paraense, 3:195 [translation of orig. descr.], August, 1901.

Putorius paraensis, Goeldi, Bol. do Museu Goeldi, 4:61, pls. 1, 2, 1904.

Mustela affinis paraensis, Hollister, Proc. Biol. Soc. Washington, 28:143, July 10, 1914.

Mustela paraensis, Allen, Bull. Amer. Mus. Nat. Hist., 35:105, April 28, 1916; Tate, Journ. Mamm., 12:253, August 24, 1931.

Mustela stolzmanni paraensis, Hall, Carnegie Instit. Washington Publ. 473:111, November 20, 1936; Hall, Physis, 16:167, pl. 1, figs. 1-4, 1939.

Type.—Male, adult or subadult, mounted; no. 848, Paris Museum; from the "Cabinet de Lisbonne 1808," originally from South America as determined from the characters of the animal; probably came from Brazil, and for the present assumed to be from Pará.On August 25, 1937, the skull was in the mounted skin and the specimen was in the position shown in the figure published by Cabrera (1914, pl. 1). Except for the loss of the distal part of the tail, and fading because of exposure to light, the specimen was in good condition. See also under remarks.Range.—Known from the south side of the Amazon River, near its mouth at Pará and Cametá, Río Tocantins, in the Tropical Life-zone of Brazil. See figure29on page221.Characters for ready recognition.—Differs fromMustela frenata, the only other geographically adjacent species of the genus, in presence of median, longitudinal, abdominal stripe of same color as upper parts and naked foot-soles, in absence of p2 and in reduced size of tympanic bullae (see pls. 29 and 30) and fromMustela africana stolzmanniby lighter color of upper parts which although near Chestnut-Brown are in adults 10'l(darker in yg. M. C. Z., no. 30802), instead of 11'nas inM. a. stolzmanni.Description.—Size.—This is a relatively large weasel. Goeldi (1897:559) gives the total length of the type specimen of hisP. b. paraensis, a female, as 520 mm. (495 in the flesh) and, by computation from his figures, the length of the tail as 200 (205 in the flesh). These measurements probably include the hairs on the tip of the tail as probably also do the measurements given of two other specimens (see Goeldi, 1904:62). One of these specimens, a female, measured: Total length, 520; length of tail, 200. The other specimen, a male, measured: Total length, 510; length of tail, 200. The skin of no. 37475, Amer. Mus. Nat. Hist., a male, has the following measurements written on the attached label: Total length, 548; length of tail, 234; length of hind foot, 56. The hairs project 20 mm. beyond the tip of the last vertebra of the tail and probably are included in the measurements of total length and length of tail. Collectors' measurements of a young male from Cametá, and a subadult labeled as male, from Pará Murutucu, are respectively as follows: 500, 430; 210, 190; 50 and 54.Externals.—Foot-soles naked, except for a few scattered hairs on ventral sides of interdigital membranes; length of claws, measured on concave sides, not more than one and one-fifth times depth of claws measured at bases; carpal vibrissae not extending beyond apical pad of first digit (not beyond hypothenar pad except in one young specimen); longest facial vibrissae not extending to posterior margin of ear; superior genal tuft not found, hairiness of foot-soles as shown in figure22.Color.—Upper parts near (10 l) Chestnut-Brown and relatively uniform since tip of tail and muzzle are only slightly darker than remainder; underparts with longitudinal stripe of same color as upper parts extending along median line of belly from throat or breast posteriorly to within 40 to 50 millimeters of anus. Underparts otherwise near (20"a) Olive-Ocher (lips and chin whiter in one young specimen). Color of underparts extends distally on median sides of forelegs to bare foot-soles and on median side of hind legs two-thirds of distance from knee to ankle. Upper lips broadly edged with whitish, which color passes posteriorly below and not touching eye to ventral margin of concha of ear. An inverted, basally broad, V-shaped extension passes upward 4 millimeters, just posterior to the eye.Skull and teeth.—See measurements (plates28-30). Male: (based on 3 adult and subadult topotypes and figures and descriptions published by Goeldi, 1897 and 1904.) Weight, 7.0 grams; basilar length, 45.8 (44.6-47.8); skull broad and deep; braincase large, rounded, and much inflated anteriorly; distance from postorbital process to anterior, nasal notch approximately equal to breadth across exoccipital condyles; palatal region wide; tympanic bullae less inflated than in any other species; mastoid bone, laterally, concave; length of upper tooth-rows in adults and subadults less than breadth of palate measured between two outer margins of fourth upper premolars; alveolar distance between C1 and P4 less than length of P4; teeth heavy; medial lobe of M1 only slightly larger than lateral lobe; deuterocone of P4 heavy and often inclined mesially; p2 absent (P2 present above on both sides in only one of seven specimens seen or described); lower jaw heavy; masseteric fossa not extending anteriorly to posterior fourth of talonid of m1; paraconid of m1 low and base of cleft between it and protoconid relatively low on tooth.Female: No skull examined but from figures published by Goeldi (1904, pl. 2), apparently as described in the male.

On August 25, 1937, the skull was in the mounted skin and the specimen was in the position shown in the figure published by Cabrera (1914, pl. 1). Except for the loss of the distal part of the tail, and fading because of exposure to light, the specimen was in good condition. See also under remarks.

Range.—Known from the south side of the Amazon River, near its mouth at Pará and Cametá, Río Tocantins, in the Tropical Life-zone of Brazil. See figure29on page221.

Characters for ready recognition.—Differs fromMustela frenata, the only other geographically adjacent species of the genus, in presence of median, longitudinal, abdominal stripe of same color as upper parts and naked foot-soles, in absence of p2 and in reduced size of tympanic bullae (see pls. 29 and 30) and fromMustela africana stolzmanniby lighter color of upper parts which although near Chestnut-Brown are in adults 10'l(darker in yg. M. C. Z., no. 30802), instead of 11'nas inM. a. stolzmanni.

Description.—Size.—This is a relatively large weasel. Goeldi (1897:559) gives the total length of the type specimen of hisP. b. paraensis, a female, as 520 mm. (495 in the flesh) and, by computation from his figures, the length of the tail as 200 (205 in the flesh). These measurements probably include the hairs on the tip of the tail as probably also do the measurements given of two other specimens (see Goeldi, 1904:62). One of these specimens, a female, measured: Total length, 520; length of tail, 200. The other specimen, a male, measured: Total length, 510; length of tail, 200. The skin of no. 37475, Amer. Mus. Nat. Hist., a male, has the following measurements written on the attached label: Total length, 548; length of tail, 234; length of hind foot, 56. The hairs project 20 mm. beyond the tip of the last vertebra of the tail and probably are included in the measurements of total length and length of tail. Collectors' measurements of a young male from Cametá, and a subadult labeled as male, from Pará Murutucu, are respectively as follows: 500, 430; 210, 190; 50 and 54.

Externals.—Foot-soles naked, except for a few scattered hairs on ventral sides of interdigital membranes; length of claws, measured on concave sides, not more than one and one-fifth times depth of claws measured at bases; carpal vibrissae not extending beyond apical pad of first digit (not beyond hypothenar pad except in one young specimen); longest facial vibrissae not extending to posterior margin of ear; superior genal tuft not found, hairiness of foot-soles as shown in figure22.

Color.—Upper parts near (10 l) Chestnut-Brown and relatively uniform since tip of tail and muzzle are only slightly darker than remainder; underparts with longitudinal stripe of same color as upper parts extending along median line of belly from throat or breast posteriorly to within 40 to 50 millimeters of anus. Underparts otherwise near (20"a) Olive-Ocher (lips and chin whiter in one young specimen). Color of underparts extends distally on median sides of forelegs to bare foot-soles and on median side of hind legs two-thirds of distance from knee to ankle. Upper lips broadly edged with whitish, which color passes posteriorly below and not touching eye to ventral margin of concha of ear. An inverted, basally broad, V-shaped extension passes upward 4 millimeters, just posterior to the eye.

Skull and teeth.—See measurements (plates28-30). Male: (based on 3 adult and subadult topotypes and figures and descriptions published by Goeldi, 1897 and 1904.) Weight, 7.0 grams; basilar length, 45.8 (44.6-47.8); skull broad and deep; braincase large, rounded, and much inflated anteriorly; distance from postorbital process to anterior, nasal notch approximately equal to breadth across exoccipital condyles; palatal region wide; tympanic bullae less inflated than in any other species; mastoid bone, laterally, concave; length of upper tooth-rows in adults and subadults less than breadth of palate measured between two outer margins of fourth upper premolars; alveolar distance between C1 and P4 less than length of P4; teeth heavy; medial lobe of M1 only slightly larger than lateral lobe; deuterocone of P4 heavy and often inclined mesially; p2 absent (P2 present above on both sides in only one of seven specimens seen or described); lower jaw heavy; masseteric fossa not extending anteriorly to posterior fourth of talonid of m1; paraconid of m1 low and base of cleft between it and protoconid relatively low on tooth.

Female: No skull examined but from figures published by Goeldi (1904, pl. 2), apparently as described in the male.

Remarks.—Desmarest in 1818 gave a remarkably good description of this animal which he named as a new species,Mustela africana, but mistakenly indicated that the single specimen known to him came originally from Africa. Until 1913 the name was applied, wrongly, to weasels of northern Africa or to those of the Azores Islands and St. Thomas Island. In that year Cabrera (1913:429) identified the species with the one later namedPutorius (Mustela) brasiliensis paraensisby Goeldi (1897:556, pl. 21) from Pará, Brazil. Despite Cabrera's clear identification in 1913, and his later mention of the correct application of the nameMustela africana, it was not correctly employed by other authors, including myself who even as late as 1936 (p. 111) instead used Goeldi's name. In 1937 Mr. Cabrera called my attention to his published account ofMustela africanaand so permitted me to examine the type specimen in the Paris Museum, whither I was bound when I received Mr. Cabrera's letter. My own examination of the specimen fully confirmed the conclusions published by Cabrera (1913:429).

As a matter of historical interest, however, it is worth noting that Cabrera (1913) originally supposed the type specimen to have been taken as booty of war from Portugal by the French and that Cabrera later, at the request of P. Trouessart, pointed out (1914:176) that the specimen had been acquired in exchange ("a cambio") since according to Dr. Trouessart the Museum register showed that offer had been made to Portugal to return this and other specimens but that Portugal had replied that it had nothing to reclaim. Dr. P. Rode in August, 1937, at the Paris Museum, gave it to me as his opinion that the specimen had been an outright gift from the "Cabinet de Lisbonne" to E. Geoffroy St.-Hilaire on his trip to Portugal in 1808 when he was given also from the same cabinet several primates, all from Brazil. Of the labels attached to the pedestal on which the specimen is mounted, that of most ancient appearance is glued to the bottom of the stand and bears in a hand apparently written before Trouessart's entries on the same label, the information "Du Cabinet de Lisbonne 1808" and "J. H. S. 1809."

The opened mouth of the mounted specimen permits one to determine that P2 is absent on each side above. The stuffed scrotal pouch and hair projecting downward about the preputial opening clearly show the animal to have been a male. The least faded portions of the mounted specimen, its sides, are of the same reddish color as characterizes adults from Pará and not of the darker chocolate color of specimens ofM. stolzmannifrom Perú. The specimen is indistinguishable from topotypes ofP. paraensisof Goeldi and his name will have to fall as a synonym ofMustela africanaDesmarest.

Goeldi gave an extended description, with figures of the skull, head, and entire animal, when he namedparaensis. As his account shows, he was unaware that Taczanowski had described a similar weasel from the headwaters of the Amazon, or for that matter that any weasel exceptingMustela affinisGray, had been found in South America. Goeldi's later account of additional specimens (1904:61, pls. 1, 2) gives much useful information about the animal. Photographs of several specimens and photographs and detailed measurements of several skulls are presented by him.

Pará, and Cametá, Brazil, places from whichMustela africana africanais known, are nearly 2000 miles from the localities in eastern Perú and eastern Ecuador from whichM. a. stolzmanniis known, and no specimens, from intermediate localities, are available to show actual intergradation of the two. However, the similarity in structure of the two weasels is so great as to indicate close affinity. Furthermore, it is understood that environmental conditions at and between the two localities are similar. These considerations, in the light of our knowledge of actual intergradation of geographic races of weasels in other places, cause me to treat, with a feeling of assurance,M. africana[=P. paraensisGoeldi] andM. stolzmanniTaczanowski as subspecies of a single species. M. Rodolpho Legueira Rodríguez writes me, under date of June 16, 1928, that the type specimen ofPutorius (Mustela) brasiliensis paraensisGoeldi is stuffed and preserved in a "vitrine" at the Museum Goeldi (Museum Paraense) De Historia Natural e Ethnographia, Pará, Brazil.

The one young specimen seen, that from Cametá, is darker colored than any of the four older specimens examined. It is almost exactly the Chestnut Brown of Ridgway (1912) and therefore approaches closely in color the adult specimens ofM. a. stolzmanni. This same tendency to greater richness of color in young than in adults is seen also inMustela frenata.

Specimens examined.—Total number, 5, all from eastern Brazil, as follows: Pará, 2 (1[2], 1[7]); Pará Murutucu, 1[7]; Río Tocantins, Cametá, 1[75]; type specimen, 1[84].

Tropical Weasel

Plates39and40

Mustela stolzmanniTaczanowski, Proc. Zoöl. Soc. London, 1881:835, November 15, 1881; Allen, Bull. Amer. Mus. Nat. Hist., 35:105, April 28, 1916.Mustela stolzmanni stolzmanni, Hall, Carnegie Instit. Washington Publ. 473:111, November 20, 1936; Hall, Physis, 16:167, pl. 1, figs. 5, 6, 1939.

Mustela stolzmanniTaczanowski, Proc. Zoöl. Soc. London, 1881:835, November 15, 1881; Allen, Bull. Amer. Mus. Nat. Hist., 35:105, April 28, 1916.

Mustela stolzmanni stolzmanni, Hall, Carnegie Instit. Washington Publ. 473:111, November 20, 1936; Hall, Physis, 16:167, pl. 1, figs. 5, 6, 1939.

Type.—Female, adult, mounted skin, with skull separate; no. 563, Mus. Polonais d'Hist. Nat. (Warsaw, Poland); Yurimaguas, Perú; 1880; obtained by J. Stolzmann.The skull (plate40), mounted with the skin but removed by me for study, consists of the premaxillae, maxillae, two halves of the lower jaw and dentition. Of these parts, right m2, left coronoid process, right P4 and M1 and adjacent part of maxilla are lost. The skin is well mounted, in a good state of preservation and shows no fading due to exposure to light. Inguinal mammae are distinctly shown on the skin and prove that the specimen is a female. Except for a few scattered hairs on the lower throat, a spot six by eight millimeters on the medial side of the region of the olecranon of the left foreleg and another of similar size in the left axilla, the underparts are, excepting the ventral longitudinal, abdominal stripe, unmarked by color of the upper parts.Range.—Known from the Tropical Life-zone of eastern Ecuador and Perú from Jatun Yacu south to Valle del Perené. See figure29on page221.Characters for ready recognition.—Differs fromMustela frenata, the only other geographically adjacent species of the genus, in presence of median, longitudinal, abdominal stripe of same color as upper parts and naked foot soles, in absence of p2 and in reduced size of tympanic bullae (see pls. 28, 29, 30, 39 and 40) and fromMustela africana africanaby darker color of upper parts which, although near Chestnut Brown, are 11'ninstead of 10'las inM. a. africana.Description.—Size.—Male: unknown.Female: Taczanowski (1881:836) gives, among others, the following measurements of the type specimen: Total length, 523, length of body, 260; length of tail without hair, 190 (with hair 224); length of hind foot, 54. Whether or not the measurements were taken from the animal when in the flesh I do not know. Allowing for shrinkage of hind feet and changes due to the posture of the now mounted specimen, I get from it essentially the same measurements. Collectors' measurements of a subadult from Moyobamba and a young female from Valle del Perené, are respectively, as follows: 469, 415; 184, 160; 57, 52. My own measurements of the dry hind feet on the skins are respectively, 48 and 49.Externals.—As described inM. a. africanaexcept that the length of the concave sides of the claws are approximately one and one-fourth times the depth; thus the claws are relatively longer than inM. a. africana.Color.—As described inM. a. africanawith the following noted exceptions: Upper parts near (11'n) Chestnut-Brown; area of lighter ventral coloration on the throat and sides of head less strongly tinged with yellow; pelage more dense, finer and softer than inM. a. africana.Skull and teeth.—Male: Skull unknown.Female: See measurements and plate39and40. As described in male ofMustela africana africanaexcept that: Weight, 4.7 grams. As contrasted withM. a. africana, the dentition of the lower jaw is lighter; the transverse diameter of m2 is 1.2 mm. in the type and also in the specimen from Moyobamba as against 1.5 to 1.7 in three male topotypes ofM. a. africana.

Type.—Female, adult, mounted skin, with skull separate; no. 563, Mus. Polonais d'Hist. Nat. (Warsaw, Poland); Yurimaguas, Perú; 1880; obtained by J. Stolzmann.

The skull (plate40), mounted with the skin but removed by me for study, consists of the premaxillae, maxillae, two halves of the lower jaw and dentition. Of these parts, right m2, left coronoid process, right P4 and M1 and adjacent part of maxilla are lost. The skin is well mounted, in a good state of preservation and shows no fading due to exposure to light. Inguinal mammae are distinctly shown on the skin and prove that the specimen is a female. Except for a few scattered hairs on the lower throat, a spot six by eight millimeters on the medial side of the region of the olecranon of the left foreleg and another of similar size in the left axilla, the underparts are, excepting the ventral longitudinal, abdominal stripe, unmarked by color of the upper parts.

Range.—Known from the Tropical Life-zone of eastern Ecuador and Perú from Jatun Yacu south to Valle del Perené. See figure29on page221.

Characters for ready recognition.—Differs fromMustela frenata, the only other geographically adjacent species of the genus, in presence of median, longitudinal, abdominal stripe of same color as upper parts and naked foot soles, in absence of p2 and in reduced size of tympanic bullae (see pls. 28, 29, 30, 39 and 40) and fromMustela africana africanaby darker color of upper parts which, although near Chestnut Brown, are 11'ninstead of 10'las inM. a. africana.

Description.—Size.—Male: unknown.

Female: Taczanowski (1881:836) gives, among others, the following measurements of the type specimen: Total length, 523, length of body, 260; length of tail without hair, 190 (with hair 224); length of hind foot, 54. Whether or not the measurements were taken from the animal when in the flesh I do not know. Allowing for shrinkage of hind feet and changes due to the posture of the now mounted specimen, I get from it essentially the same measurements. Collectors' measurements of a subadult from Moyobamba and a young female from Valle del Perené, are respectively, as follows: 469, 415; 184, 160; 57, 52. My own measurements of the dry hind feet on the skins are respectively, 48 and 49.

Externals.—As described inM. a. africanaexcept that the length of the concave sides of the claws are approximately one and one-fourth times the depth; thus the claws are relatively longer than inM. a. africana.

Color.—As described inM. a. africanawith the following noted exceptions: Upper parts near (11'n) Chestnut-Brown; area of lighter ventral coloration on the throat and sides of head less strongly tinged with yellow; pelage more dense, finer and softer than inM. a. africana.

Skull and teeth.—Male: Skull unknown.

Female: See measurements and plate39and40. As described in male ofMustela africana africanaexcept that: Weight, 4.7 grams. As contrasted withM. a. africana, the dentition of the lower jaw is lighter; the transverse diameter of m2 is 1.2 mm. in the type and also in the specimen from Moyobamba as against 1.5 to 1.7 in three male topotypes ofM. a. africana.

Remarks.—After the Polish naturalist, Stolzmann, in the course of his explorations in Perú, obtained the single specimen which was made the type, no other naturalist, so far as known, visited the type locality until thirty-two years later when Wilfred H. Osgood and M. P. Anderson spent more than a month collecting at Yurimaguas (see Osgood, 1914:147), but secured no topotypes of this little-known weasel. C. O. Schunke took the second specimen in the Valle del Perené in April, 1921; L. Rutter on January 25, 1924, took the third specimen, and W. Clark-MacIntyre took the fourth specimen on the Jatun Yacu. This obscure place name is shown on the map (fig. 4, p. 827) published by Brown (1941) and is the stream flowing from the west to the town of Napo. Napo is situated at approximately 1° 2' S and 77° 49' W.

In the female from Moyobamba there are only 3 pairs of mammae. One pair is inguinal and two pairs are on the posterior part of the abdomen.

Taczanowski (1881:836) relates that this species was taken in the forest to which it appears to be restricted since the inhabitants of the village did not know of the animal. He points out also that the previously known Peruvian species [M. f. macruraandM. f. agilis] live in the treeless territory of eight to eleven thousand feet altitude whereasM. stolzmanniwas found in the humid forest of the great plain of the Maynas at an elevation of 500 feet or less above sea level. The frontal sinuses of the specimens seen reveal no malformation as a result of infestation by parasites.

Specimens examined.—Total number, 4, as follows:Ecuador: R. Tatun [= Jatun] = Yacu, 1, Mus. Comp. Zoöl.Perú: Yurimaguas, 1 in Mus. Polonais d'Hist. Naturelle, Warsaw; Moyobamba, 2700 ft. [6° S, 77° W], 1 in Brit. Mus. Nat. Hist.; Valle del Perené, 1200 meters, 1 in Amer. Mus. Nat. Hist.

Specimens examined.—Total number, 4, as follows:

Ecuador: R. Tatun [= Jatun] = Yacu, 1, Mus. Comp. Zoöl.

Perú: Yurimaguas, 1 in Mus. Polonais d'Hist. Naturelle, Warsaw; Moyobamba, 2700 ft. [6° S, 77° W], 1 in Brit. Mus. Nat. Hist.; Valle del Perené, 1200 meters, 1 in Amer. Mus. Nat. Hist.

EXPLANATION OF CRANIAL MEASUREMENTS APPEARS ON PAGE 417

Fig. 31.Four views of the skull and a lateral view of the left lower jaw to show points between which measurements of the skull were taken. Based onM. f. primulina, from 3 mi. E Bergman, Boone County, Arkansas, obtained December 12, 1933, by B. G. Roberts; ad. ♀. 62854 Mus. Vert. Zoöl. × 1-2/5.

Basilar length (of Hensel).—From the anteriormost border of the foramen magnum to a line connecting the posterior margins of the alveoli of the first upper incisors. F to F' on fig.31.Condylobasal length.—Least distance from a line connecting the posteriormost parts of the exoccipital condyles to a line connecting the anteriormost projections of the premaxillary bones.Length of tooth-rows.—Least distance between a line connecting posterior borders of upper molars and a line connecting anterior faces of middle upper incisors. G to G' on fig.31.Breadth of rostrum.—Least distance from lateral base of hamular process of lacrimal bone to corresponding point on opposite side of skull. B to B' on fig.31.Interorbital breadth.—Least distance across top of skull between orbits (eye sockets). O to O' on fig.31.Orbitonasal length.—Distance on anterior part of skull from posterior margin of base of postorbital process of frontal bone to posteriormost part of anterior border of nasal bone on same side of skull. A to A' on fig.31.Mastoid breadth.—Greatest distance across mastoid bones perpendicular to long axis of skull. E to E' on fig.31.Zygomatic breadth.—Greatest distance across zygomatic arches of cranium perpendicular to long axis of skull. D to D' on fig.31.

Basilar length (of Hensel).—From the anteriormost border of the foramen magnum to a line connecting the posterior margins of the alveoli of the first upper incisors. F to F' on fig.31.

Condylobasal length.—Least distance from a line connecting the posteriormost parts of the exoccipital condyles to a line connecting the anteriormost projections of the premaxillary bones.

Length of tooth-rows.—Least distance between a line connecting posterior borders of upper molars and a line connecting anterior faces of middle upper incisors. G to G' on fig.31.

Breadth of rostrum.—Least distance from lateral base of hamular process of lacrimal bone to corresponding point on opposite side of skull. B to B' on fig.31.

Interorbital breadth.—Least distance across top of skull between orbits (eye sockets). O to O' on fig.31.

Orbitonasal length.—Distance on anterior part of skull from posterior margin of base of postorbital process of frontal bone to posteriormost part of anterior border of nasal bone on same side of skull. A to A' on fig.31.

Mastoid breadth.—Greatest distance across mastoid bones perpendicular to long axis of skull. E to E' on fig.31.

Zygomatic breadth.—Greatest distance across zygomatic arches of cranium perpendicular to long axis of skull. D to D' on fig.31.

Tympanic bulla:

Length.—From posterior face to most anterior part of anterior border. H to H' on fig.31.Breadth.—From bottom of pit immediately posterior to external auditory meatus to medial face of bulla at right angle with longitudinal axis of skull. J to J' on fig.31.Depth.—Least distance from ventral face of basioccipital, excluding median ridge, to line touching ventralmost points of the two bullae. L to L' on fig.31.

Length.—From posterior face to most anterior part of anterior border. H to H' on fig.31.

Breadth.—From bottom of pit immediately posterior to external auditory meatus to medial face of bulla at right angle with longitudinal axis of skull. J to J' on fig.31.

Depth.—Least distance from ventral face of basioccipital, excluding median ridge, to line touching ventralmost points of the two bullae. L to L' on fig.31.

m1, Length.—Greatest length which rarely or never is alveolar length.

P4.—

Lateral.—Length from posterior margin of tooth to anteriormost part of the protocone (anterolateral cusp).Medial.—Length from the posterior margin of tooth to anteriormost part of the deuterocone (anterointernal cusp).

Lateral.—Length from posterior margin of tooth to anteriormost part of the protocone (anterolateral cusp).

Medial.—Length from the posterior margin of tooth to anteriormost part of the deuterocone (anterointernal cusp).

M1.—

Breadth.—Distance from medial edge of crown to lateral margin of crown, approximately at a right angle with longitudinal axis of the skull.Length.—Greatest diameter, anteroposteriorly, of the inner lobe or inner half of the tooth.

Breadth.—Distance from medial edge of crown to lateral margin of crown, approximately at a right angle with longitudinal axis of the skull.

Length.—Greatest diameter, anteroposteriorly, of the inner lobe or inner half of the tooth.

Depth of skull at anterior margin of basioccipital.—Measured from anterior end of ventral face of basioccipital, excluding median ridge, vertically to dorsal face of parietal excluding sagittal crest. K to K' on fig.31.Depth of skull at posterior borders of Ms1.—Measured from ventral face of palatine bones at posterior edge of upper molars to dorsal face of frontals in plane of postorbital processes of frontals. S to S' on fig.31.

Depth of skull at posterior borders of Ms1.—Measured from ventral face of palatine bones at posterior edge of upper molars to dorsal face of frontals in plane of postorbital processes of frontals. S to S' on fig.31.

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