Mustela lutreola

Abstract

Mustela lutreola (Linnaeus, 1761) European Mink Viverra lutreola Linnaeus, 1761:5. Type locality restricted to southwest Finland by Matschie, 1912:347. Mustela lutreola Linnaeus, 1766:66. First use of current name combination. Lutra minor Erxleben, 1777 :451, a renaming of lutreola Linnaeus. Lutreola europeae von Homeyer, 1879:184, substitute name for lutreola Linnaeus. CONTEXT AND CONTENT. Order Carnivora, Family Mustelidae, Genus Mustela, Subgenus Lutreola. The genus Mustela includes 16 extant species (Honacki et al., 1982). Heptner (1967) recognized five subspecies of Mustela lutreola, but these were not accepted by Ognev (1931) or Youngman (1982). DIAGNOSIS. Mustela lutreola often is confused with the forest polecat (Mustela putorius) and American mink (Mustela vison). In M. lutreola, guard hairs and underfur are brown while in M. putorius the guard hairs are blackish and the underfur is light grey to light buff. In M. lutreola, the depth of the rostrum at the anterior edge of the fourth upper premolar is barely equal to the distance from the fourth upper premolar to the anterior margin of the premaxillary, instead of considerably greater as in M. putorius In M. lutreola, the breadth across the postorbital processes is about the same as the greatest width of the occipital condyles, while in M. putorius the breadth across the postorbital processes is considerably larger than the width of the occipital condyles. In M. lutreola, the postpalatal length is much larger than the mastoidal breadth, while in M. putorius it is approximately the same. In M. lutreola, the angle between the lingual and buccal arms of the fourth upper premolar is approximately 90°, while in M. putorius the angle is greater causing the junction to be broadly U-shaped. M. lutreola differs from M. vison in having both upper and lower lips white, whereas M. vison usually has only the lower lip white. The bullae of M. lutreola are narrow and almond-shaped, and anteriorly overhang the surrounding bone, whereas the bullae of M. vison are broad and triangular in palatal view. Their anterior margins are straight and do not overhang the surrounding bone. The second upper pre-molar is single-rooted in M. lutreola, but usually double-rooted in M. vison. In M. lutreola the lingual arm of the fourth upper premolar is about equal in length to the buccal arm, while in M. vison the lingual arm is the longer (Youngman, 1982). GENERAL CHARACTERS. A medium-sized mustelid with a long body, short legs, and a relatively short tail. Feet with inter-digital membranes as in other members of the genus. Hair covering of body and tail relatively uniform in length. Soles of feet sparsely haired. The coloration of the European mink is a dark reddish-brown with a white margin around the mouth. Occasionally there are white throat, paw, and chest markings. Winter pelage is longer and denser than that of summer (Heptner, 1967; Novikov, 1939). Averages and standard deviations of external measurements (in mm) and mass of seven males from France are: total length, 377.8 ± 14.39; length of tail, 163.5 ± 12.82; mass, 870.7 ± 152.68 g (range, 650-1,005 g). Measurements (in mm) of two females from France are: total length, 315, 310; length of tail, 120, 120; mass, 580 g, 505 g. Averages and standard deviations of cranial measurements (in mm) of 11 males and seven females, respectively, are condylobasallength, 63.53 ± 1.97 and 58.17 ± 1.93; palatal length, 28.54 ± 1.11 and 25.83 ± 0.97; zygomatic breadth, 36.13 ± 1.64 and 32.20 ± 0.78; mastoidal breadth, 30.90 ± 0.97 and 28.51 ± 0.57. The skull (Fig. 1) is narrow and dorsoventrally flattened. The dorsal outline is only slightly curved. The distance from the palation to the condylion is considerably greater than the mastoidal breadth (Youngman, 1982). DISTRIBUTION. The historic distribution of the European mink (Fig. 2) was from the Basque region of northern Spain in the west, to the Ob River basin in the east (Ternovskii, 1977), and from near Archangel in the north to the Caucasus in the south (Youngman, 1982). Novikov (1939) reported an extensive range extension (900 km) of M. lutreola through the Urals from 1871 to 1932. Youngman (1982) proposed that M. lutreola first migrated to France in the early 19th century, reaching Bordeaux by 1942 and Dax by 1950, and that recent (1950-1960) reports of the European mink in Spain were a continuation of this range expansion. The present distribution of the species is much reduced, poorly known, and diminishing (Tumanov and Zverev, 1986; Youngman, 1982). FOSSIL RECORD. The ancestry of M. lutreola is unknown.