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Mammals are among the fastest-radiating groups, being charac terized by a mean species lifespan of the order of 2.5 million years Changes in organisms occur on a variety of temporal scales. Four basic temporal scales (tiers) have been recognized: the ecological timescale; the Milankovitch timescale of precession (the wobbling of the Earth's axis, �21 kyr periodicity), obliquity (tilt of the Earth's axis, 41 kyr periodicity) and eccentricity (the orbit around the Sun, � 100 and �400 kyr periodicity); the million-year timescale of species extinctions and originations; and the ultra-long timescale of mass extinctions and major taxonomic replacements9. Although the main processes controlling the fi rst tier (climate change and competition), the second tier (climate-forced distributional vari ation)3,9,IO and the fourth tier (catastrophic perturbations of the Earth's biosphere) are reasonably well defi ned, the mechanisms underlying third-tier processes are not well ill1derstood. Mammals have featured importantly in discussions on the processes pertaining to this tier2-7• Because their mean species duration is estimated at 2.3-2.6 Myr (refs 1, 2), primary (20-400kyr) Milankovitch vari ations cannot be held responsible for mammal speciation and extinction4,9,lo. It has been suggested that amplitude changes of climatic oscillations could have played a part in explaining turn over3,1O, but until now no efforts have been made systematically to compare such amplitude variations with turnover in long and well dated records.We compiled a data set of more than 200 rodent assemblages from Central Spain (see Supplementary Notes and Supplementary Ta ble 1) and analysed it in terms of turnover. The record is exceptionally long (22 Myr) , largely continuous, dense and well dated. We focused on rodents, because screen sieving allows the collection of large amounts of easily identifi able dental elements. The studied fossils originate from fl uvio-Iacustrine sections in the Madrid, Calatayud-Daroca and Te ruel basins, and amount to over 80,000 isolated molars, which were identifi ed at the species and lineage level (132 lineages, pseudo extinctions ignored). All studied localities are positioned in strati graphic sections, a large number of which have been tied to the geomagnetic polarity timescale by first-order correlations. The complete temporal sequence was calibrated to the new astronomi cally tuned timescale for the Neogene11 (Supplementary Fig. 1). The use of this new timescale is of crucial importance because it allows a direct comparison -with time series of the Earth's orbital parameters outlined above.Randomization procedures were used to capture uncertainties in the ages oflocalities (by the generation of a series of equally probable age models) and of fi rst and last rodent appearances, resulting in 1,000 equally probable time series. Sample size effects on the presence or absence of rodents were observed to be fairly small and were further reduced by inferring lineage presence on a range-through basis and by excluding...

ContextResults. The magnetic field is found to be globally horizontal with a relatively weak field strength (8-15 Gauss). On the other hand, the Ca II movie reveals turbulent-like motion that is not organized in specific parts of the prominence. We tested the addition of a turbulent magnetic component. This model is compatible with the polarimetric observations at those places where the plasma turbulence peaks. On the other hand, the Mg II line profiles show multiple peaks well separated in wavelength. This is interpreted by the existence of small threads along the line of sight with a large dispersion of discrete values of Doppler shifts, from 5 km s −1 (a quasi-steady component) to 60-80 km s −1 . Each peak corresponds to a Gaussian profile, and not to a reversed profile as was expected by the present non-LTE radiative transfer modeling. This is a very surprising behavior for the Mg II line observed in prominences. Conclusions. Turbulent fields on top of the macroscopic horizontal component of the magnetic field supporting the prominence give rise to the complex dynamics of the plasma. The plasma with the high velocities (70 km s −1 to 100 km s −1 if we take into account the transverse velocities) may correspond to condensation of plasma along more or less horizontal threads of the arch-shape structure visible in 304 Å. The steady flows (5 km s −1 ) would correspond to a more quiescent plasma (cool and prominence-corona transition region) of the prominence packed into dips in horizontal magnetic field lines. The very weak secondary peaks in the Mg II profiles may reflect the turbulent nature of parts of the prominence.

Context. The dynamics of prominence fine structures present a challenge to our understanding of the formation of cool plasma prominence embedded in the hot corona. Aims. Observations performed by the high resolution Hinode/SOT telescope allow us to compute velocities perpendicular to the lineof-sight or transverse velocities. Combining simultaneous observations obtained in Hα with Hinode/SOT and the MSDP spectrograph operating in the Meudon solar tower, we derive the velocity vectors of a quiescent prominence. Methods. The velocities perpendicular to the line-of-sight are measured using a time-slice technique and the Doppler shifts velocity using the bisector method.Results. The Doppler shifts of bright threads derived from the MSDP show counterstreaming of the order of 5 km s −1 in the prominence and reaching 15 km s −1 at the edges of the prominence. Even though they are minimum values because of seeing effects, they are of the same order as the transverse velocities. Conclusions. These measurements are very important because they suggest that the vertical structures detected by SOT may not be true vertical magnetic structures in the sky plane. The vertical structures could be a pile up of dips in more or less horizontal magnetic field lines in a 3D perspective, as proposed by many MHD modelers. In our analysis, we also calibrate the Hinode Hα data using MSDP observations obtained simultaneously.

Among rodents, the lineage from Progonomys hispanicus to Stephanomys documents a case of increasing size and dental specialization during an approximately 9 Myr time-interval. On the contrary, some contemporaneous generalist lineages like Apodemus show a limited morphological evolution. Dental shape can be related to diet and can be used to assess the ecological changes along the lineages. Consequently, size and shape of the first upper molar were measured in order to quantify the patterns of morphological evolution along both lineages and compare them to environmental trends. Climatic changes do not have a direct influence on evolution, but they open new ecological opportunities by changing vegetation and allow the evolution of a specialist like Stephanomys. On the other hand, environmental changes are not dramatic enough to destroy the habitat of a long-term generalist like Apodemus. Hence, our results exemplify a case of an influence of climate on the evolution of specialist species, although a generalist species may persist without change.