To examine phylogenetic relationships within the Asian lineage of voles (Microtus) belonging to subgenus Alexandromys, the mitochondrial cytochrome b gene (cytb) was sequenced for its representatives, and the results were compared with the cytogenetic, morphological, and paleontological data. In all the trees inferred from maximum likelihood, parsimony, and Bayesian phylogenetic analyses, the Asian clade is subdivided into highly supported Alexandromys s.s. and moderately supported Pallasiinus lineages. Four subclades are recovered within Alexandromys: (1) Microtus maximowiczii and Microtus sachalinensis; (2) Microtus miiddendorffii s.l., Microtus mongolicus and Microtus gromovi; (3) Microtus fortis; and (4) Microtus limnophilus. Thus, M. limnophilus demonstrates clear affinities to Alexandromys s.s. but not to Microtus oeconomus (subgenus Pallasiinus), which was always regarded as its sibling species. The results obtained indicate M. mongolicus as a member of Alexandromys but not of the Microtus arvalis group, thus being concordant with the cytogenetic data. The mitochondrial data support the species status of M. gromovi; moreover, its placement as a part of a trichotomy with M. miiddendorffii s.l. and M. mongolicus contradicts the traditional affiliation of M. gromovi with M. maximowiczii. The divergence rate of cytb third position transversions in Microtus is estimated at approximately 8% per Myr, which corresponds to approximately 30% per Myr for all substitution types at all codon positions. The maximum likelihood distance based on complete sequence showed a tendency for a progressive underestimation of divergence and time for older splits. According to our molecular clock analysis employing nonlinear estimation methods, the split between Alexandromys and Pallasiinus and basal radiation within Alexandromys date back to approximately 1.2 Mya and 800 Kya, respectively.

AimWe assessed the influence of past environmental changes, notably the importance of palaeogeographical and climatic drivers, in shaping the distribution patterns of Dipodoidea (Rodentia), the superfamily most closely related to the large species-rich superfamily Muroidea (c. 1300-1500 species). Dipodoids are suitable for testing several biogeographical hypotheses because of their disjunct distribution patterns in the Northern Hemisphere and the numerous species distributed in Asian deserts.Location Holarctic.Methods We inferred molecular phylogenetic relationships for Dipodoidea (34 out of 51 species and 15 out of 16 genera) based on five coding genes. A time-calibrated phylogeny was estimated using a Bayesian relaxed molecular clock with four fossil calibrations. A cross-validation procedure was adopted to examine the impact of each fossil on our estimates. The ancestral area of origin and biogeographical scenarios were reconstructed using time-stratified dispersal-extinction-cladogenesis models.Results Phylogenetic analyses recovered a well-resolved and supported topology. The divergence between Dipodoidea and Muroidea occurred in the late Palaeocene (c. 57.72 Ma) and modern Dipodoidea diversified during the middle Eocene (c. 40.62 Ma). Similar results were found with each calibration strategy used with the cross-validation procedure. The reconstruction of ancestral areas and biogeographical events indicated that modern Dipodoidea originated in the Himalaya-Tibetan and Central Asian region.Main conclusions At the time when Dipodoidea diversified (middle Eocene), the Central Asia and Himalaya-Tibetan Plateau region experienced major uplift episodes due to the collision of India with Asia, which also induced diversification events in many other groups. Other important diversification events (e.g. divergence between Zapodidae and Dipodidae in Central Asia) took placed during the Eocene-Oligocene transition when the global temperature decreased significantly and rodent/lagomorph-dominant faunas replaced Eocene perissodactyl-dominant faunas. All of these climatic and geological disruptions in the Central Asia and Himalaya-Tibetan Plateau region modified landscapes and offered new habitats that favoured diversification events, thus triggering the evolutionary history of Dipodoidea.

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We explored the patterning of genetic diversity within white-toothed shrews of the genus Crocidura from 14 localities across Vietnam. An analysis of cytochrome oxidase c subunit I (COI) and cytochrome b (cytb) gene fragments from 185 specimens of white-toothed shrews of the genus Crocidura from 14 localities across Vietnam revealed six deeply divergent (p-distance for both COI and cytb >10%) lineages, corresponding to the morphological species C. sokolovi, C. zaitsevi, C. phuquocensis, С . indochinensis, C. tanakae and, C. phanluongi. Crocidura sokolovi was distinct from all other Vietnamese white-toothed shrews (~13% on average for both cytb and COI). In addition to demonstrating the genetic separation of previously described species, substantial cryptic genetic diversity was revealed. Crocidura zaitsevi and C. tanakae each included two subgroups that corresponded to geographically remote localities, while C. indochinensis contained two distinct subgroups that exhibited co-varying patterns of morphological and ecological differentiation, suggesting that the individuals from Sa Pa represent a separate species (provisionally named Crocidura sp. AB1). Mitochondrial data generated for the type specimens of C. phanluongi from Yok Don and Bu Gia Map supported the validity of the species while an additional specimen from Binh Chau, South Vietnam originally referred to C. phanluongi exhibited a deep genetic split (cytb: 8.4%; COI: 8.7%) from a neighbouring population in Yok Don. We propose that the specimen from Binh Chau also represents an undescribed species (provisionally named Crocidura sp. AB2). Our cytb data were then compared to the sequences of 28 species of Crocidura from Southeast Asia available in GenBank, suggesting that three more species occur in northern Vietnam, namely C. wuchihensis, C. attenuata and C. fuliginosa/C. dracula. The discovery of fairly deep genetic divergences among Vietnamese Crocidura illustrates that the understudied and largely undescribed diversity of white-toothed shrews in Southeast Asia requires deeper scrutiny. It also shows the useful insights of mitochondrial markers as to the taxonomic resolution of this enigmatic group of mammals.

The subfamilies Erinaceinae and Galericinae of the extant family Erinaceidae are the only living representatives of the once diverse taxon Erinaceomorpha. In the present study, we performed the first multilocus analysis of phylogenetic relationships among genera of Erinaceidae and estimated the split times between and within the two subfamilies. The analyses of five nuclear and two mitochondrial genes produced a well-resolved molecular phylogeny. Generally, the molecular tree is compatible with the morphology-based taxonomy proposed by Frost, Wozencraft & Hoffmann with the exception of the position of Mesechinus, which is placed as the closest sister taxon of Hemiechinus. Another point of contradiction between molecular and morphological phylogenies is the position of Hylomys megalotis, which was consistently placed as the most basal branch among all gymnures in molecular analyses. Genetic relationships between Erinaceus and Atelerix remain unclear, suggesting a hard trichotomy among these two lineages and Hemiechinus + Paraechinus. Molecular dating suggests an ancient origin of the extant gymnure lineages, which date back to the late Eocene to early Oligocene. The age of the basal split within spiny hedgehogs is relatively recent and corresponds to the Miocene-Pliocene boundary. Possible changes to the erinaceid taxonomy are considered.