Postcanine dental form in the mustelidae and viverridae (Carnivora: Mammalia)

This study investigates whether the gross morphology of mustelid and viverrid postcanine dentitions corresponds with differences in diet. For each species, the predominant foods ingested are used to form predictions of dental form and measurements of the carnassial and molar teeth determine the extent of shearing and crushing surfaces on the postcanine teeth. Principal components analysis distinguishes species according to morphological differences in the dentition and these differences are compared with predictions of dental form based on diet. Dietarily specialized species are more likely to be correspondingly specialized in the dentition and species with varied food sources are more likely to possess dental characteristics that are generalized in function. Consumers of foods with high fracture resistance, such as vertebrate tissue and hard-surfaced invertebrates, possess specialized shearing or crushing postcanine teeth. On the other hand, species that consume foods of lesser fracture resistance, such as fruit and soft invertebrates, differ greatly in dental form and are more generalized in dental function. A few species possess postcanine dentitions that do not correspond with diet; the absence of dental-dietary correlation in these species suggests that other factors, such as phylogeny, are important in determining dental form.     

Genetic variation and population structure in Scandinavian wolverine (Gulo gulo) populations

Wolverine (Gulo gulo) numbers in Scandinavia were significantly reduced during the early part of the century as a result of predator removal programmes and hunting. Protective legislation in both Sweden and Norway in the 1960s and 1970s has now resulted in increased wolverine densities in Scandinavia. We report here the development of 15 polymorphic microsatellite markers in wolverine and their use to examine the population sub-structure and genetic variability in free-ranging Scandinavian wolverine populations as well as in a sample of individuals collected before 1970. Significant subdivision between extant populations was discovered, in particular for the small and isolated population of southern Norway, which represents a recent recolonization. Overall genetic variability was found to be lower than previously reported for other mustelids, with only two to five alleles per locus and observed heterozygosities (H(O)) ranging from 0.269 to 0.376 across the examined populations, being lowest in southern Norway. Analysis of the mitochondrial DNA control region revealed no variation throughout the surveyed populations. As the historical sample did not show higher levels of genetic variability, our results are consistent with a reduction in the genetic variation in Scandinavian wolverines that pre-dates the demographic bottleneck observed during the last century. The observed subdivision between populations calls for management caution when issuing harvest quotas, especially for the geographically isolated south Norwegian population.     

Characterization of oligosaccharides in milk of a mink, Mustela vison

Carbohydrates were extracted from a sample of milk from a mink, Mustela vison (Family Mustelidae). Free neutral and acidic oligosaccharides were isolated from the carbohydrate fraction and their chemical structures were compared with those of white-nosed coati (Nasua narica, Procyonidae) and harbour seal (Phoca vitulina, Phocidae) that we had studied previously. The ratio of free lactose to milk oligosaccharides was similar to that in milk of the white-nosed coati; in both species, this ratio was much lower than that in the milk of most eutherians. The neutral oligosaccharides of mink milk had alpha(1-3)-linked Gal or alpha(1-2)-linked Fuc residues at their non-reducing ends, as in the neutral oligosaccharides of white-nosed coati milk. Some of the neutral and acidic oligosaccharides, determined here, had been found also in harbour seal milk, but the harbour seal oligosaccharides did not contain alpha(1-3)-linked Gal residues.     

Size patterns among competitors: ecological character displacement and character release in mammals, with special reference to island populations

Morphological relationship among sympatric animal species have often been seen as indirect evidence for competition. Many early ecomorphological studies revealed patterns that were taken as indicating character displacement and character release, driven by competition or lack thereof. These patterns may result from a coevolutionary morphological response or from species sorting according to size. Thus, the relationship between morphology and competition may be crucial for understanding both the morphological evolution of animals and the role of competition in structuring communities. Some earlier research perceived as indicating morphological relationships conditioned by interaction of species was conducted on mammals, particularly carnivores. Subsequent criticism in the ecological literature demonstrated that many of the perceived patterns could not be statistically confirmed, thus calling into question this line of evidence for competition. More recent ecological literature relies on strong statistical analyses and careful consideration both of guild composition and of which morphological traits should be examined. This literature, resting largely on mammals, includes several cases that suggest a coevolutionary morphological response to interspecific competition. These studies have focused on the thropic apparatus directly related to food procurement by mammals — the teeth. Island mammals often show striking morphological patterns, some of which have been interpreted as resulting from release from competition with mainland species that have not reached islands. However, few of these patterns were critically evaluated to demonstrate their support for the hypothesis of character release. Despite several decades of interest and research, many questions regarding competitively induced morphological patterns remain unresolved and require further research. Mammals are especially promising subjects for such researh.     

Mustela or Vison? Evidence for the taxonomic status of the American mink and a distinct biogeographic radiation of American weasels

The American mink’s relationship to the weasels in Mustela has been uncertain. Karyological, morphological, and phylogenetic comparisons to Eurasian Mustela support placing the mink outside the genus as Neovison vison. However, genetic comparisons that incorporate other endemic American Mustela suggest the interpretation of N. vison’s position to Mustela has been handicapped by biased geographic sampling. Here, we analyzed mitochondrial cytochrome-b from all weasels endemic to the Americas, including two poorly known South American species (M. felipei, M. africana), weasels native to North America (M. vison, M. frenata, M. nigripes), Mustela migrant to North America (M. erminea, M. nivalis), palearctic Mustela, and other American members of Mustelidae. Bayesian and likelihood inference methods were used to construct a phylogeny of Mustela, and relaxed Bayesian phylogenetic techniques estimated ages of divergence within the genus using priors calibrated by fossil ages. Our analyses show that the American mink and the smaller Mustela endemic to the Americas represent a distinct phylogenetic heritage apart from their Eurasian cousins, and biogeographic barriers like the Bering and Panamanian land bridges have influenced the evolutionary history of Mustela in the Americas.     

Camera trap records of leucistic Eurasian badgers (Meles meles) in central Norway

Coat coloration plays an important role in communication, camouflage, and sexual selection in animals. Genetic mutations can lead to anomalous colorations such as melanism and leucism, where animals appear, respectively, darker or lighter than normal. Reporting abnormal coloration in wild animals is an important first step to understand the distribution, prevalence, and potential fitness consequences of these rare events. Here, we report several records of suspected leucism in the Eurasian badger (Meles meles) in a population in central Norway. Several camera traps recorded at least two leucistic individuals between 2017 and 2020. It took considerable effort, almost 400,000 camera trap nights over a period of 10 years all over Norway, to obtain a total of eleven records of leucistic badgers, indicating the rarity of this phenotype. It is unclear what has caused the presence of multiple leucistic badgers in a single population, but recent colonization and lack of predators might have played a role. Due to our observations, future studies can now be developed to study the underlying mechanisms and potential consequences of leucism in this badger population. The increasing use of networks of camera traps in wildlife research will provide new opportunities to record rare coloration in wild animals.     

Estrous cycle of the tayra,Eira barbara

Thirty-three estrous cycles of three female tayras were defined using vaginal cytology and/or behavioral observations. Estrous cycles averaged 56.0 ± 4.73 and 52.2 ± 15.5 days in length for two young tayras and 93.9 ± 21.0 for an older female. The complete absence of parabasal cells in vaginal smears coincided with vulvar tumescence and was diagnostic of estrus.     

江苏铜山上新世Promephitis一新种

本文记述了一个采自江苏铜山的原臭鼬类头骨化石.根据铜山标本自身的特征以及与 P. maeotica、P. lartetii 和 P. alexejewi 等相近类型的比较,我们认为它不同于目前已知的任何原臭鼬种,而是 Iromephitis 属中—新成员——P. maxima sp. nov.,其地质时代为上新世.