Barremian and Aptian (Cretaceous) sharks and rays from Speeton, Yorkshire, north-east England

Bulk sampling of a number of horizons within the upper part of the Speeton Clay Type section has produced teeth and other remains of sharks and rays from several poorly studied horizons. At least 10 shark and two ray species were recorded, with two sharks, Pteroscyllium speetonensis and Palaeobrachaelurus mitchelli, being described as new. The oldest occurrences of the family Anacoracadae and the genus Pteroscyllium, as well as the youngest occurrence of the genus Palaeobrachaelurus, were recorded. The palaeoenvironmental significance of the faunas is briefly discussed

Révision de quelques Odontaspididae (Neoselachii: Lamniformes) du Paléocène et de l'Eocène du Bassin de la mer du Nord

The revision of some Odontaspididae species from the Paleocene and the Eocene of the North sea Basin has clarified the generic status of some of them and to precise their dental morphologies. A species from the Lutetian of Belgium, Carcharias sp., can be considered as the first representative of the lineage leading to the Recent species C. taurus. Three new genera are described: Brachycarcharias nov. gen. (Lutetian of Belgium), Orpodon nov. gen. (Selandian of Belgium) and Sylvestrilamia nov. gen. (Ypresian of England). The validity of the genus Hypotodus is confirmed and it is recommended that the poorly defined species hopei is abandoned in favour of the species verticalis in order to avoid confusion

High resolution spectroscopy of the three dimensional cosmic web with close QSO groups

We study the three-dimensional distribution of matter at z~2 using high resolution spectra of QSO pairs and simulated spectra drawn from cosmological hydro-dynamical simulations. We present a sample of 15 QSOs, corresponding to 21 baselines of angular separations evenly distributed between ~1 and 14 arcmin, observed with the Ultraviolet and Visual Echelle Spectrograph (UVES) at the European Southern Observatory-Very Large Telescope (ESO-VLT). The observed correlation functions of the transmitted flux in the HI Lya forest transverse to and along the line of sight are in agreement, implying that the distortions in redshift space due to peculiar velocities are relatively small and - within the relatively large error bars - not significant. The clustering signal is significant up to velocity separations of ~300 km/s, corresponding to about 5 h^{-1} comoving Mpc. Compatibility at the 2 sigma level has been found both for the Auto- and Cross-correlation functions and for the set of the Cross correlation coefficients. The analysis focuses in particular on two QSO groups of the sample. Searching for alignments in the redshift space between Lya absorption lines belonging to different lines of sight, it has been possible to discover the presence of a wide HI structures extending over about ten Mpc in comoving space, and give constraints on the sizes of two cosmic under-dense regions in the intergalactic medium.Comment: Accepted by MNRAS, version matching the published on

Hybodont sharks of the English Bathonian and Callovian (Middle Jurassic).

Recent bulk sampling and study of museum collections has revealed a high diversity of hybodont sharks from the English Bathonian, with 15 species being recognised. In addition, study of dental and skeletal material from the English Callovian has allowed the diagnosis of a new genus and species, Planohybodus peterboroughensis gen. et sp. nov., allowing the Bathonian species Hybodus grossiconus Agassiz to be referred to Planohybodus. Two additional new genera, Secarodus and Frangerodus, are erected for the Bathonian taxa Hybodus polyprion Agassiz and Strophodus lingualis Woodward, respectively. Egertonodus duffini sp. nov. is described and the diagnosis of Egertonodus based on dental material is discussed. The previously unrecorded Hybodus sp., Parvodus sp., and Lonchidion sp. are recognised but left in open nomenclature. Asteracanthus medius (Owen) is recorded in the British Bathonian for the first time, and the status of Bathonian nominal species of Asteracanthus are assessed. Bathonian hybodonts showed great diversity in trophic ecology and many of the species are specific to particular palaeoenvironments

Otolithes de poissons pliocènes du sud-est de la France

Otoliths collected from nine localities in the Lower and Middle Pliocene blue marls of southern France revealed the presence of 118 teleost taxa, including 80 named species. Three new species are introduced: Pseudophichthys escaravatierensis, "genus Bythitinorum" vonhachti and Cepola neogenica. The associations studied belong to five different biozones of planktonic foraminifera in the Lower and Middle Pliocene. The relationships of these Pliocene teleost faunas to the Tortonian and Recent Mediterranean faunas are analysed. Because major problems exist in matching otolith-based species with those erected for osteological material from Messinian localities, our comparisons are based exclusively on data obtained from the otoliths. Fifty of our 80 identified species appear only in the Pliocene. This indicates that at the beginning of the Piocene, the Mediterranean realm was subject to extensive faunal replacement. All the studied associations indicate higher temperatures than those of the present day Mediterranean. In the studied area, the associations from the basal Pliocene (Spaeroidinellopsis Acme-zone) at Saint-Martin-du-Var clearly indicate a bathyal environment, corresponding to depths of 300-500 m or even more. Ascending the stratigraphic column, the successive associations in the Pliocene rias of Southeastern France indicate decreasing depths, corresponding to the progressive filling of these basins. In the studied area, data on the teleosts of the terminal Pliocene are lacking, but faunas of this age are known from Southern Italy. They show that the Paleomediterranean fauna, which was substantially modified at the beginning of the Pliocene, appears near the end of this period as a warm water fauna, trapped in a basin where deterioration of climatic conditions led progressively to extinction. The Recent bathyal fauna of the Mediterranean appears extremely impoverished, but the littoral fauna conserves certain aspects of warmer waters, as is apparent in the prolific evolution of gobiids, labrids and blenniids

A catalogue of bright (K <9) M dwarfs

Using the Position and Proper Motion Extended-L (PPMXL) catalogue, we have used optical and near-infrared colour cuts together with a reduced proper motion cut to find bright M dwarfs for future exoplanet transit studies. PPMXL's low proper motion uncertainties allow us to probe down to smaller proper motions than previous similar studies. We have combined unique objects found with this method to that of previous work to produce 8479 K <9 M dwarfs. Low-resolution spectroscopy was obtained of a sample of the objects found using this selection method to gain statistics on their spectral type and physical properties. Results show a spectral-type range of K7-M4V. This catalogue is the most complete collection of K <9 M dwarfs currently available and is made available here.Peer reviewe

Sharks of the order Carcharhiniformes from the British Coniacian, Santonian and Campanian (Upper Cretaceous).

Bulk sampling of phosphate-rich horizons within the British Coniacian to Campanian (Upper Cretaceous) yielded very large samples of shark and ray teeth. All of these samples yielded teeth of diverse members of the Carcharhiniformes, which commonly dominate the fauna. The following species are recorded and described: Pseudoscyliorhinus reussi (Herman, 1977) comb. nov., Crassescyliorhinus germanicus (Herman, 1982) gen. nov., Scyliorhinus elongatus (Davis, 1887), Scyliorhinus brumarivulensis sp. nov., ? Palaeoscyllium sp., Prohaploblepharus riegrafi (Müller, 1989) gen. nov., ? Cretascyliorhinus sp., Scyliorhinidae inc. sedis 1, Scyliorhinidae inc. sedis 2, Pteroscyllium hermani sp. nov., Protoscyliorhinus sp., Leptocharias cretaceus sp. nov., Palaeogaleus havreensis Herman, 1977, Paratriakis subserratus sp. nov., Paratriakis tenuis sp. nov., Paratriakis sp. indet. and ? Loxodon sp. Taxa belonging to the families ?Proscylliidae, Leptochariidae, and Carcharhinidae are described from the Cretaceous for the first time. The evolutionary and palaeoecological implications of these newly recognised faunas are discussed