Despite some popularity of hamsters as pets and laboratory animals there is no reliable phylogeny of the subfamily Cricetinae available so far. Contradicting views exist not only about the actual number of species but also concerning the validity of several genera. We used partial DNA sequences of two mitochondrial (cytochrome b, 12S rRNA) and one partial nuclear gene (von Willebrand Factor exon 28) to provide a first gene tree of the Cricetinae based on 15 taxa comprising six genera. According to our data, Palaearctic hamsters fall into three distinct phylogenetic groups: Phodopus, Mesocricetus, and Cricetus-related species which evolved during the late Miocene about 7-12 MY ago. Surprisingly, the genus Phodopus, which was previously thought to have appeared during the Pleistocene, forms the oldest clade. The largest number of extant hamster genera is found in a group of Cricetus-related hamsters. The genus Cricetulus itself proved to be not truly monophyletic with Cricetulus migratorius appearing more closely related to Tscherskia, Cricetus, and Allocricetulus. We propose to place the species within a new monotypic genus. Molecular clock calculations are not always in line with the dating of fossil records. DNA based divergence time estimates as well as taxonomic relationships demand a reevaluation of morphological characters previously used to identify fossils and extant hamsters.

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The Quaternary dispersal of the red fox Vulpes vulpes in the Mediterranean area was evaluated through the study of allelic variation at 45 enzyme loci in 120 individuals from 10 sampling sites. A 375 bp fragment of the mitochondrial cytochrome b gene was also sequenced in a total of 41 specimens from the same sampling locations. Nine allozyme loci were polymorphic. The proportion of polymorphic loci per population (P) ranged from 0 to 15.6%, and expected average heterozygosity (H) from 0 to 4.4%. A total of 18 different Cyt b haplotypes were detected. Most of them were con®ned to only one population. Both allozyme and mtDNA data implied that our fox populations were genetically fairly isolated from one another, suggesting low gene¯ow between them. This isolation should be of comparatively recent origin according to the slight differentiation among Cyt b haplotypes. Fox populations appeared to belong to two genetically distinct groups. With a mean value of Nei's D = 0.024, genetic distance between these groups was similar to that detected at subspecies level in taxa of large mammals. This pattern may have originated from different colonization waves during Quaternary glaciations and deglaciations. Red foxes from Sardinia were more closely related to the Bulgarian foxes than to the Iberian ones. However, repeated introductions to Sardinia probably also occurred from Central Italy and Spain, as suggested by the presence of haplotype A and a typical Central Italian allele, Ck-2 90 .