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Mustela africana Desmarest, 1818, is a mustelid commonly called the tropical or Amazon weasel and is South America's largest weasel. It has dark pelage with little variation in color on the dorsum; the venter is pale colored with a dark medial longitudinal stripe, matching the color of the dorsum. The species is endemic to the Amazon Basin. Known from about 30 records over 2 centuries from different localities of Brazil, Ecuador, and Peru, it may be one of the rarest carnivores in South America. Globally, it is considered “Least Concern” by the International Union for Conservation of Nature and Natural Resources. GERAL CHARACTERS Mustela africana presents an elongate body and neck, small head, and short ears and legs. The pelage is short, uniformly chestnut brown or reddish with little variation along the body but the nose is darker. As in other Neotropical weasels, young individuals have darker pelage than adults, and pelage color varies geographically, with western populations dark brown and eastern populations more reddish. The venter is pale orange-tan with a midventral stripe of the same color as the dorsum (Taczanowski 1881; Pine 1973). The ventral stripe can extend to the forelegs or the throat and in some specimens it extends to the base of the chest and then splits into 2 or 3 semicontinuous segments ending on the neck (Orcés 1944; Izor and de la Torre 1978). The facial vibrissae are short and do not reach the posterior margin of the ear (Taczanowski 1881; Hall 1951). The soles of the feet are naked, with a few scattered hairs on ventral sides of interdigital membranes (Hall 1951). Mean external measurements (mm; with parenthetical ranges [when appropriate], n—compiled from Taczanowski 1881; Goeldi 1901; Goeldi and Hagmann 1904; Hall 1951; Izor and de la Torre 1978; Izor and Peterson 1985) of adult (mixed sexes) M. a. africana were: total length, 510 (430–522, 7); length of tail, 200 (2), 192 (168–210, 4); length of hind foot, 53.3 (50–56, 3); length of ear, 18 (2). Mean external measurements (mm; with parenthetical ranges [when appropriate], n—compiled from Taczanowski 1881; Goeldi 1901; Goeldi and Hagmann 1904; Hall 1951; Izor and de la Torre 1978; Izor and Peterson 1985) of adult (mixed sexes) of M. a. stolzmanni, were: total length, 476 (430–523, 2), 425 (415–435, 2); length of tail, 175 (160–190, 2); length of hind foot, 53 (52–54, 3); length of ear, 21 (20–22, 2). Additional external measurements are available (Taczanowski 1881; Goeldi 1901; Goeldi and Hagmann 1904; Hall 1951; Izor and de la Torre 1978; Izor and Peterson 1985). The skull presents a large and rounded braincase, anteriorly inflated; wide palatal region; tympanic bullae less inflated than other South American species of the genus; and a reduced angle of lower jaw. The dentary is heavy with the masseteric fossa not extending anteriorly to the posterior one-fourth of talonid of ml (Hall 1951). Mean craniodental measurements (mm; with parenthetical range—compiled from Goeldi and Hagmann 1904; Hall 1951; Izor and Peterson 1985) of 3 males of M. a. africana were: condylobasal length, 45.8 (44.6–47.8); zygomatic breadth, 29.5 (26.8–32.2); least interorbital breadth, 11.3 (10.2–12.9); length of upper toothrow, 16.7 (16.4–17.2). For adult males and females of M. a. stoltzmanni mean craniodental measurements (mm, parenthetical ranges [when appropriate], n) were: condylobasal length, 51.2 (1 male), 46.7 (44.6–49.8, 3 females); zygomatic breadth, 30.4 (1 male), 28.86 (28.81–28.90, 2 females); least interorbital breadth, 12.2 (1 male), 11.3 (11.0–12.0, 3 females); length of upper toothrow, 16.1 (1 male), 16.8 (16.0–17.5, 3 females). Additional cranial measurements are available (Goeldi and Hagmann 1904; Hall 1951; Izor and Peterson 1985). DISTRIBUTION Mustela africana is known from few localities (Fig. 3) located south of the Amazon River in Brazil and its tributaries in eastern Ecuador and Peru (the Napo, the Marañón, and the Ucayali) over an elevational range from 0 to 1,250 m (Schreiber et al. 1989; Tirira 2017; Ramírez-Chaves et al. 2017). The limits of the range of distribution are poorly known and the species may be distributed in the Amazon Basin of Colombia and northern Bolivia (Alberico et al. 2017; Emmons and Helgen 2017). No fossils are known. Geographic distribution of records of Mustela africana and its distribution according to the World Conservation Union (stipple—Emmons and Helgen 2017). Plotting symbols are: plus signs, M. a. africana; dotted circles, M. a. stolzmanni, question mark, M. cf. africana. Locality codes are: a, Rio Jatún Yacu (Museum of Comparative Zoology, Harvard University [MCZ] 36324); b, Maracacuera–Icoaraci (Pine 1973); c, Zoological Garden (American Museum of Natural History [AMNH] 37475); d, Murutucú, Capinsal (British Museum of Natural History [BMNH] 26.1.8.10); e, Pará (British Museum of Natural History [BMNH] 5.1.25.1); f, Marco de Legoa, near to the city (Goeldi 1898); g, Puyo (Orcés 1944); h, Belém, Ramal de Pinheiro (Pine 1973); I, Irituía (Pine 1973); j, Rio Tocantins, Cametá (Museum of Comparative Zoology, Harvard University [MCZ] 30802); k, Belterra, a rubber plantation 25 km S, 26 km W Santarém (Izor and Peterson 1985); l, Tauarí, Rio Tapajos, about 30 km south of Belterra (Izor and Peterson 1985); m, Alto Amazonas, Río Marañón (American Museum of Natural History [AMNH] 98552); n, Yurimaguas (Taczanowski 1881); o, Moyobamba (British Museum of Natural History [BMNH] 24.12.12.24); p, Municipality of Humaitá, west of the Rio Madeira (Ferrari and Lopes 1992); q, Chanchamayo (National Museum of Natural History, Smithsonian Institution [USNM] 255119); r, Valle del Río Perené (American Museum of Natural History [AMNH] 61813); s, Rio Juruá, Cruzeiro do Sol (Field Museum of Natural History [FMNH] 106488). FORM AND FUNCTION The baculum of Mustela africana has a slender shaft that becomes broad and shallow in its distal part and possesses wide margins at the level of the dorsal bend. It presents a trifid tip with the medial and right lateral processes connected by a thin and translucent layer of bone. The trifid tip is a character shared with M. felipei (Izor and Peterson 1985). The dental formula is i 3/3, c 1/1, p 2–3/2, m 1/2, total 30–32, and the dentition is specialized for a carnivorous diet. The teeth are robust; the medial lobe of Ml is slightly larger than the lateral lobe; and the deuterocone of P4 is heavy and usually inclined mesially (Hall 1951). P2 can be absent or present, and is generally absent in M. a. stolzmanni (Izor and de la Torre 1978). The p2 is absent; a small p2 is present in Colombian specimens of both M. felipei and M. frenata. In mature M. africana, the 2 temporalis muscles meet at the midline of the skull at or anterior to the level of the glenoid fossa (Izor and de la Torre 1978). A female from Moyobamba, Peru, deposited at the Natural History Museum (BMNH 24.12.12.24) has 3 pairs of mammae, 1 pair inguinal and the other 2 on the posterior part of the abdomen (Hall 1951). Little is known of the habitat preferences and natural history of Mustela africana, apart from the places where the specimens have been found. Semiaquatic life has been suggested by its naked foot soles with interdigital webbing (Schreiber et al. 1989), although these traits are found in other mustelids (e.g., Gulo and Martes) with terrestrial and arboreal habits. More direct evidence comes from observations of its swimming abilities; a specimen in the Goeldi Museum was captured during the day while swimming in a brackish estuary in Pará, Brazil, nearly one-half mile from shore (Tate 1931). Four weasels ed as this species were sighted foraging together in the lower canopy of forest along the Rio Madeira (7°33′S, 63°12′W), Amazonas, Brazil, but the identification of these Mustela could not be confirmed (Ferrari and Lopes 1992). Specimens also were found in a willow tree in Moyobamba, Peru (Hall 1951), in a rubber plantation in Brazil (Izor and Peterson 1985), and burrowing in a hollow tree stump (Emmons and Feer 1990). One individual was found in humid forest of Maynas, Loreto, Peru, at an elevation of 150 m (Taczanowski 1881; Hall 1951). A specimen was captured alive in a trap baited with maize and banana and set near a house, in a rubber plantation located in Belterra, Pará, Brazil (Izor and Peterson 1985). GETICS Phylogenetic analysis using sequences of the mitochondrial cytochrome-b indicates that Mustela africana is the sister species of M. felipei, with a divergence time from M. frenata estimated at about 3–4 million years ago. These 3 species, together with Neovison vison (formerly Mustela), comprise a distinct New World lineage that is sister to 2 Southeastern Asian species and then to a large diverse Holarctic lineage (Harding and Smith 2017). The cytochrome-b sequence of M. africana was obtained from a Brazilian specimen (FMNH 106488) housed at the Field Museum of Natural History, Chicago, Illinois. CONSERVATION Mustela africana is only known from a few specimens but seemingly is widespread throughout Amazonia (Schreiber et al. 1989; Oliveira 2017). Globally, it is considered “Least Concern” by the International Union for Conservation of Nature and Natural Resources; however, it may qualify as “Data Deficient” because almost nothing is known of its ecology, threats, and distribution (Emmons and Helgen 2017). Previous assessments for Brazil and Ecuador included the species in “Data Deficient” based on the unknown status and apparent rarity of the species (Machado et al. 2017; Tirira 2017). The species was considered the least known carnivore of Brazil (Oliveira 2017), although it may occur in large national parks of Amazonia (Schreiber et al. 1989), including National Parks Sumaco-Napo Galeras and Yasuní in Ecuador (Tirira 2017). ACKNOWLEDGMENTS We thank A. Muñoz-Quintero and L. Idárraga for literature, and P. Velazco and the American Museum of Natural History for photographs of the skin and skull of AMNH 37475. HER-C thanks B. Ramírez Padilla, B. Hegedues, V. Weisbecker, and the University of Queensland (UQCent and UQI scholarships) for support. Three anonymous reviewers contributed to clarifying this article. © 2017 American Society of Mammalogists 网站原创范文除特殊说明外一切图文作品权归所有；未经官方授权谢绝任何用途转载或刊发于媒体。如发生侵犯作品权现象，英语论文，保留一切法学追诉权。() 更多范文欢迎访问我们主页 当然有需求可以和我们 关系交流。-X()，英语论文范文 |
