The geography and timing of genetic divergence in the lizard Phrynocephalus theobaldi on the Qinghai-Tibetan plateau.

The Qinghai-Tibetan Plateau (QTP) represents one of the earth's most significant physical features and there is increasing interest in the historical generation of biodiversity within this region. We hypothesized that there should be clear geographically coherent genetic structuring within one of the world's highest altitude lizards, Phrynocephalus theobaldi, due to considerable historical population fragmentation in this environment. This was tested using a major mitochondrial DNA (mtDNA) survey and sequencing of two nuclear markers (AME and RAG-1) from P. theobaldi, from across the southern QTP. A Bayesian method (BPEC) was used to detect four geographically structured mtDNA clusters. A Bayesian phylogenetic tree, together with associated dating analyses, supported four corresponding evolutionary lineages with a timing of 3.74-7.03 Ma for the most basal P. theobaldi split and Pliocene splits of 2.97-5.79 Ma and 2.40-5.39 Ma in the two daughter lineages. Himalayan uplift and changes in the Jilong basin may have contributed to these divergences, but uplift of the Gangdese mountains is rejected due to its timing. The nuclear markers appeared to be sorted between the four mtDNA groups, and species delimitation analyses supported the four phylogeographical groups as candidate species. The study contributes to our understanding of biodiversity on the QTP

Tonian deltaic and storm-influenced marine sedimentation on the edge of Laurentia: the Veteranen Group of northeastern Spitsbergen, Svalbard

The Hecla Hoek succession of northeastern Svalbard, Norway, is an ~7 km thick Tonian– Ordovician sedimentary succession that overlies Stenian–Tonian felsic igneous and metasedimentary rocks. The carbonate-dominated upper Tonian–Ediacaran (ca. 820–600 Ma) Akademikerbreen and Polarisbreen groups have yielded important insights into Earth’s Neoproterozoic climate, environment, and biological evolution. However, the underlying siliciclastic-dominated lower Tonian (ca. 950–820 Ma) Veteranen Group has garnered little attention despite the fact that it is remarkably well-preserved and hosts diverse microfossil assemblages. Here, we present the first detailed sedimentological analysis of the Veteranen Group from a continuous ~4.4 km thick stratigraphic section at Faksevågen, Ny Friesland, Spitsbergen. Integrated facies analysis, sequence stratigraphy, and carbonate δ13Ccarb and δ18 Ocarb chemostratigraphy elucidate the early depositional history of the Hecla Hoek basin and provide fundamental paleoenvironmental constraints for future investigations of this succession as an archive of Tonian Earth History. The Veteranen Group records a long-lived deltaic and storm influenced marine sedimentary system that reveals dynamics of Precambrian clastic sedimentation prior to the evolution of land plants. Five asymmetric transgressive-regressive (T-R) sequences within the Veteranen Group thin upwards, providing support for the hypothesis that the contact with the Akademikerbreen Group represents a rift-to-drift transition. This complex record of Tonian deltaic and storm-influenced marine sedimentation along the Laurentian margin strengthens correlation between the Veteranen Group and coeval strata from East Greenland and sets the stage to better understand the Proterozoic tectonic evolution of the North Atlantic–Circum34 Arctic region following the Grenville orogeny