Long-term evolution of the North Anatolian Fault: new constraints from its eastern termination

The deformation and40Ar–39Ar dating of recent volcanism, that remarkably sits across the North Anatolian Fault eastern termination in Turkey, together with previous studies, put strong constraints on the long-term evolution of the fault. We argue that after a first phase of 10 Ma, characterized by a slip rate of about 3 mm/a, and during which most of the trace was established, the slip rate jumped to about 20 mm/a on average over the last 2.5 Ma, without substantial increase of the fault length. The transition correlates with a change in the geometry at the junction with the East Anatolian Fault that makes the extrusion process more efficient.

Colonization history, ecological shifts and diversification in the evolution of endemic Galápagos weevils

Mitochondrial DNA sequence data were obtained for eight species of flightless Galapaganus endemic weevils and one winged close relative in order to study their colonization history and modes of diversification in the Galápagos Archipelago. Contrary to most other insular radiations, the phylogeny estimates we recovered for Galapaganus do not follow the progression rule of island biogeography. The penalized likelihood age estimates of colonization of the archipelago exceed the age of the emerged islands and underscore the potential role of now sunken seamounts for the early evolution of Galapaganus. The phylogeny proposes one intra-island origin for Galapaganus endemics, but monophyly tests suggest a larger contribution of in-situ speciation on older islands. Generalist habitat preferences were reconstructed as ancestral while shifts to highland habitats were reconstructed as having evolved independently on different islands. Magnitudes and patterns of diversification rate were found to differ between older and younger islands. Our analyses reveal that the colonization sequence of islands and timing of colonization of Galapaganus could be linked with the geological and volcanic history of the islands in a rather complex scenario. Even though most islands appear to have been colonized soon after their emergence, there are notable deviations from the pattern of sequential colonization expected under the progression rule when considering only the extant emerged islands. Patterns of diversification rate variation on older and younger islands correspond to the volcanic activity or remnants of such activity, while the pattern of independent evolution of restricted habitat preferences in different islands suggests that habitat shifts could also have contributed to species diversity in Galapaganus.