Diversity and paleoenviromental significance of Brazilian fossil Galictis (Carnivora: Mustelidae)

The evolutionary history of the genus Galictis in South America probably begins after the Great American Biotic Interchange. Two species are recognised: Galictis vittata and Galictis cuja. The latter are more frequently found in open areas in southern South America and the first occurs in humid forests from northern South America to Central America. Apparently, they do not occur in sympatry. Both are differentiate by the presence of a metaconid in the first inferior molar of G. vittata and for its bigger size when compared to G. cuja. The fossil record of Galictis is scarce, G. cuja is known by few specimens from Argentina, Chile and Brazil; G. vittata have only one record from Southern Brazil. The specimens related to this record were collected by Peter Lund and are housed at the Statens Naturhistoriske Museum. However, the specimens published by Lund are not fossils. Thus, it is presented here other unpublished specimens collected by Lund and housed at the same museum that we recognise as the first G. vittata fossils. Additionally, it is described here the first fossil record for G. cuja from the late Pleistocene of Brazil – an almost complete mandible recovered from sedimentary deposits from Central Brazil.     

Three-dimensional fibre-type distribution in the paravertebral muscles of the domestic ferret (Mustela putorius f. furo) with relation to functional demands during locomotion

We investigated the functional corollaries of a relatively long trunk with regard to trunk use during overground and underground locomotion and with regard to fibre-type distribution within the paravertebral musculature using the example of the domestic ferret. Fibre-type distribution was determined using enzyme histochemistry on serial cross-sections through the complete musculo-skeletal apparatus. Back posture and back movements were analysed using cineradiography. During overground locomotion, the back is bent into an arch, resulting in a back length comparable to normally proportioned small mammals. During underground locomotion, the back is held straight, resulting in greater rotational inertia and higher stabilisation requirements. This is reflected in the fibre-type distribution pattern, which differs clearly from that of all other mammals investigated so far. Instead of being separated into superficial, glycolytic and deep, oxidative parts, all the epaxial and the iliopsoas muscles consisted of 20-30% oxidative, 20-30% oxidative-glycolytic and 40-60% glycolytic fibres, with no or only minor differences between superficial and profound muscles or muscle regions. Only the quadratus lumborum muscle showed a fibre-type distribution comparable to other mammals, reflecting its primary function as an accessory muscle of respiration. We suggest that the observed pattern reflects the adaptation of the back muscles to the functional demands of a long trunk and the increased need to stabilise it during overground and especially underground locomotion.     

Polygynandry, extra-group paternity and multiple-paternity litters in European badger (Meles meles) social groups

The costs and benefits of natal philopatry are central to the formation and maintenance of social groups. Badger groups, thought to form passively according to the resource dispersion hypothesis (RDH), are maintained through natal philopatry and delayed dispersal; however, there is minimal evidence for the functional benefits of such grouping. We assigned parentage to 630 badger cubs from a high-density population in Wytham Woods, Oxford, born between 1988 and 2005. Our methodological approach was different to previous studies; we used 22 microsatellite loci to assign parent pairs, which in combination with sibship inference provided a high parentage assignment rate. We assigned both parents to 331 cubs at > or = 95% confidence, revealing a polygynandrous mating system with up to five mothers and five fathers within a social group. We estimated that only 27% of adult males and 31% of adult females bred each year, suggesting a cost to group living for both sexes. Any strong motivation or selection to disperse, however, may be reduced because just under half of the paternities were gained by extra-group males, mainly from neighbouring groups, with males displaying a mixture of paternity strategies. We provide the strongest evidence to date for multiple-paternity litters, and for the first time show that within-group and extra-group males can sire cubs in the same litter. We investigate the factors that may play a role in determining the degree of delayed dispersal and conclude that the ecological constraints hypothesis, benefits of philopatry hypothesis, and life history hypothesis may all play a part, as proposed by the broad constraints hypothesis.     

Food habits of the American mink Mustela vison in the Mazurian Lakeland, Northeastern Poland

Food habits of the American mink Mustela vison were studied based on the analysis of 2364 scat samples, collected at three lakes in Northeastern Poland. The mink preyed on a wide range of prey, but two types of prey, amphibians and fish, dominated in the diet of the mink during all the seasons. Frogs, and first and foremost, the common frog Rana temporaria, were hunted by the mink, mainly from the late autumn until the early spring, and comprised up to 83.9% of the prey biomass (the multiannual average for November–December at the Majcz Wielki Lake). The most frequently eaten fish were cyprinids and percids. Seasonality of fish consumption by mink was not as well pronounced as in the case of amphibians. At the first two lakes, fish were hunted mainly in the winter and in the early spring, whereas at the third lake in the summer. The highest multiannual average share of fish in the diet of the mink was recorded in March–April at Lake Tuchlin (69.2% of the prey biomass). Crayfish, which were recorded in the diet mainly in the late spring and in the summer, comprised up to 59.6% of the prey biomass for May–June at the Majcz Wielki Lake. Birds, mammals and insects were supplementary food for the mink. During the breeding season, mink predation on waterfowl and their broods was correlated with the abundance of crested grebe Podiceps cristatus and coot Fulica atra nests in the area. The diet of individual mink varied considerably and the share of birds in the diet of the mink was related to the distance from individual mink dens to the colonies of waterfowl. In May–June, adult birds, chicks and eggs comprised up to 73.6% of the prey biomass of a female mink that inhabited a den located 100 m from the colony's edge. At all three lakes, the diet of the mink was the most diverse in the late spring and in the summer. In May–August, the values of the mink food niche breadths were about twice those noted in winter months.     

Pleistocene Carnivora (Mammalia) from Tighennif (Ternifine), Algeria

The site of Tighennif (= Ternifine) in Northern Algeria, well-known for its Homo mauritanicus (= Homo rhodesiensis?) remains, and probably dating to the late Calabrian, yielded a large assemblage of terrestrial carnivores. Some are identical or probably identical with extant species: Crocuta crocuta and Hyaena hyaena (Hyaenidae), Felis silvestris (Felidae), Mellivora capensis and Poecilictis cf. libyca (Mustelidae), and Vulpes cf. rueppelli (Canidae). In addition, among felids there is an unidentified leopard-like form; a smaller, more common species assigned to Lynx sp. (a genus quite rare in Africa) but which is certainly different from modern forms, an Homotherium that seems to be the last occurrence of the machairodonts in Africa, and a Panthera aff. leo, which is unfortunately too poorly known to be named. Rare bears do not display all derived features of later North African U. bibersoni. Among canids, the Nyctereutes-like jackal Lupulella mohibi is an endemic North African form known until the late middle Pleistocene, and the hunting dog Lycaon magnus is also clearly distinct from the modern species. A single new species is described, Enhydrictis hoffstetteri, a large, otter-like member of the Mustelidae, of a genus that was previously unknown from Africa, and certainly testifies to North–South dispersal across the Mediterranean at some time during the early Pleistocene.     

Guild composition and mustelid morphology – character displacement but no character release

Aim  Competition is hypothesized to lead to the evolution of reduced morphological overlap between competitors. Within guilds, this is believed to lead to overdispersed size ratios of the trophic apparatus of adjacent-sized species. In allopatry, conditions are believed to favour character release. We examined whether character displacement is prevalent in mainland musteline guilds and sought evidence for character release in adjacent island guilds.
Location  Holarctic, from Japan through western Europe to Pacific North America.
Methods  We measured skulls and canines of members of the mustelid subfamily Mustelinae and examined whether size ratios tend towards equality. We then examined whether insular guilds are characterized by larger size ratios and a higher degree of sexual size dimorphism than mainland guilds, and whether this reflects evolution towards the size of missing guild members.
Results  We found equal ratios between skull lengths but not canine diameters in all mainland guilds. Few insular guilds showed equal ratios for either trait. There was scant evidence for character release: insular mustelines do not evolve towards the size of a missing guild member, nor is sexual size dimorphism greater on islands. There was no evidence for a lower limit on the size similarity of co-existing mustelids.
Main conclusions  We propose that different guild compositions in different localities produce different evolutionary trajectories. Similar sizes on islands and mainlands can be explained by similar prey sizes in both settings. Morphological evidence suggests that competition is probably not a ubiquitous force in the assembly and evolution of musteline guilds.     

美国内布拉斯加州中新统的美獾化石一新种(英文)

记述了采自美国内布拉斯加州中新统的一保存较完整的美獾（Ｌｅｐｔａｒｃｔｕｓ）头骨化石。与美獾属的其他已知种相比,该标本的颊齿粗壮,Ｐ４臼齿化,近方形,宽略大于长,齿尖磨蚀均匀,Ｉ３犬齿化,且向大齿方向弯曲;Ｍ１宽略大于长,且比已知种的Ｍ１大;听泡具钩状突,突起上有一明显的舌骨关节面。依据上述与已知种的差别,我们将其定为一新种Ｌｅｐｔａｒｃｔｕｓｍａｒｔｉｎｉｓｐ ｎｏｖ。新种的牙齿形态及齿尖磨蚀状况显示其为杂食动物。     

Phylogenetic relationships within the extant Mustelidae (Garnivora): appraisal of the cladistic status of the Simpsonian subfamilies

Cladistic analysis of extant mustelids based on a data matrix consisting of 30 characters derived from morphological study of the head skeleton in all 23 genera, and 16 characters gleaned from the literature, yielded 75 most parsimonious trees with a consistency index of 0.487 using PAUP 3.0s. The analysis strongly supports the monophyly of both the Mephitinae (skunks) and Lutrinae (otters). The Mustelinae (weasels, martens, wolverine, etc) is probably paraphyletic, but there is some support for a monophyletic group consisting of the mustelines and the honey badger Mellivora. The Melinae (badgers) is a polyphyletic group; the badger ecomorph probably evolved independently at least three times within the Mustelidae. On consensus trees, there is a lack of resolution concerning the relationships within the Mephitinae and Lutrinae and the positions of Galictis and Mustela. These results are broadly congruent with a cladistic interpretation of Simpson's intent in his influential 1945 classification. Thus, a paraphyletic Mustelinae is consistent with Simpson's conception of a horizontal grouping, whereas the Mephitinae and Lutrinae represent vertical divergent lineages. In contrast, the cladistic status of the Melinae is not consistent with Simpsonian classificatory principles. The status of the monotypic Mellivorinae cannot be evaluated without considering its putative fossil members; however, the clustering of Mellivora with the badger Taxidea is not consistent with Simpson's scheme. Some of the more inclusive clades in the most parsimonious trees are vulnerable to minor changes to the data matrix. The fossil record is consistent with the basic outlines of the cladistic pattern and explains various ostensible biogeographic anomalies. Bootstrap analysis identified marked variation in the support for the components of the cladistic pattern.     

Genetic structure of North American wolverine (Gulo gulo) populations

Wolverines (Gulo gulo) are found in low densities throughout their circumpolar distribution. They are also potentially susceptible to human-caused population fragmentation (development, recreation and fur harvesting). The combination of these factors has contributed to this species being listed as having either vulnerable or endangered status across much of its current range. The effects of inherently low densities and anthropogenic pressures on the genetic structure and variation of wolverine populations are, as yet, unknown. In this study, 461 individuals were typed at 12 microsatellite loci to investigate the population genetic structure of wolverines from north-western Alaska to eastern Manitoba. Levels of gene flow and population differentiation among the sampled regions were estimated via a genotype assignment test, pairwise F(ST), and two genetic distance measures. Our results suggest that wolverine populations from southernmost regions, in which anthropogenic factors are strongest, revealed more genetic structuring than did northern populations. Furthermore, these results suggest that reductions in this species' range may have led to population fragmentation in the extreme reaches of its southern distribution. The continued reduction of suitable habitat for this species may lead to more populations becoming isolated remnants of a larger distribution of northern wolverines, as documented in other North American carnivore species.