Michael A Taylor

The trophic structure of the biota of the Peterborough Member, Oxford Clay Formation (Jurassic), UK

The Peterborough Member of the Oxford Clay Formation is organic-rich and contains an abundance of well-preserved vertebrate and invertebrate fossils. A high nutrient input supported a diverse biota. Phytoplankton was exceptionally abundant in the surface water, and formed the basis for an intricate food web in both surface and bottom waters. Top predators include some of the largest known Mesozoic marine reptiles. A giant teleost fish was analogous to modern filter feeding whales and sharks. Benthic faunas depended on organic matter sinking from surface waters, and two parallel food webs may have existed. Trophic partitioning allowed the higher level predators to become diverse, especially the plesiosaurs. Productivity was high in the surface waters, probably high in the mid-water column, and high on the sea floor at times, although benthic diversity may have been reduced due to substrate consistency and/or dysoxia. Bacterial activity within the sediment was also intense. The contribution of organic material to the sea floor was high, but heterotrophic reworking probably reduced the abundance considerably during early diagenesis. A decrease in organic carbon content in the Upper Callovian and Lower Oxfordian parts of the Oxford Clay Formation parallels a decreasing abundance of vertebrate fossils.

Cranial anatomy of a new plesiosaur genus from the lowermost Lias (Rhaetian/Hettangian) of Street, Somerset, England

ABSTRACT A newly prepared plesiosaur skull collected by Thomas Hawkins (1810–1889) from the Lias quarries of Street, Somerset, England, provides important indications of character polarity within the Plesiosauria. Many features of the 3-dimensional, matrix-free skull are seemingly plesiomorphic in accord with the early, probably latest Rhaetian, stratigraphic position of the specimen. The small supratemporal fenestrae, elongate jugals, deeply excavated cheek, spatulate mandibular symphysis, and other characters thus have important implications for phylogenetic studies of the Plesiosauria. A new genus is erected to include the skull and several other specimens of historical importance that comprise part of the oldest known fauna of fully articulated plesiosaurs.

The role of combination anthelmintic formulations in the sustainable control of sheep nematodes.

Combinations of anthelmintics with a similar spectrum of activity and different mechanisms of action and resistance are widely available in several regions of the world for the control of sheep nematodes. There are two main justifications for the use of such combinations: (1) to enable the effective control of nematodes in the presence of single or multiple drug resistance, and (2) to slow the development of resistance to the component anthelmintic classes. Computer model simulations of sheep nematode populations indicate that the ability of combinations to slow the development of resistance is maximised if certain prerequisite criteria are met, the most important of which appear to concern the opportunity for survival of susceptible nematodes in refugia and the pre-existing levels of resistance to each of the anthelmintics in the combination. Combinations slow the development of a resistant parasite population by reducing the number of resistant genotypes which survive treatment, because multiple alleles conferring resistance to all the component anthelmintic classes must be present in the same parasite for survival. Individuals carrying multiple resistance alleles are rarer than those carrying single resistance alleles. This enhanced efficacy leads to greater dilution of resistant genotypes by the unselected parasites in refugia, thus reducing the proportion of resistant parasites available to reproduce with other resistant adults that have survived treatment. Concerns over the use of anthelmintic combinations include the potential to select for resistance to multiple anthelmintic classes concurrently if there are insufficient parasites in refugia; the potential for shared mechanisms of resistance between chemical classes; and the pre-existing frequency of resistance alleles may be too high on some farms to warrant the introduction of certain combinations. In conclusion, anthelmintic combinations can play an important role in resistance management. However, they are not a panacea and should always be used in accordance with contemporary principles for sustainable anthelmintic use.

A plesiosaur from the Linksfield erratic (Rhaetian, Upper Triassic) near Elgin, Morayshire

Synopsis An apparent series of eight plesiosaurian cervical vertebrae and an isolated tooth are described from the Rhaetian (or possibly Lower Jurassic) erratic block at Linksfield, Elgin, Morayshire. The vertebrae are comparable to Rhaetian and Hettangian material from SW England, especially the Rhaetian species Plesiosaurus costatus Owen, 1840 and Plesiosaurus rugosus Owen, 1840. The vertebrae comprise a rare occurrence of associated Rhaetian plesiosaurian skeletal material.

Picosecond metrology of laser-driven proton bursts

Tracking primary radiation-induced processes in matter requires ultrafast sources and high precision timing. While compact laser-driven ion accelerators are seeding the development of novel high instantaneous flux applications, combining the ultrashort ion and laser pulse durations with their inherent synchronicity to trace the real-time evolution of initial damage events has yet to be realized. Here we report on the absolute measurement of proton bursts as short as 3.5±0.7 ps from laser solid target interactions for this purpose. Our results verify that laser-driven ion acceleration can deliver interaction times over a factor of hundred shorter than those of state-of-the-art accelerators optimized for high instantaneous flux. Furthermore, these observations draw ion interaction physics into the field of ultrafast science, opening the opportunity for quantitative comparison with both numerical modelling and the adjacent fields of ultrafast electron and photon interactions in matter.

The first Lower Jurassic dinosaur from Scotland: limb bone of a ceratosaur theropod from Skye

Synopsis A partial right tibia of a carnivorous dinosaur is reported from the Lower Jurassic Broadford Beds Formation of southern Strath, Skye. The bone consists of the proximal end and shaft of a tibia, and this shows characteristic features of the ceratosaur theropods, a group of medium-sized predatory dinosaurs that were widespread during the Early Jurassic. This tibia, and a partial sauropod tibia from the Middle Jurassic of Skye, represent the first clear records of dinosaur body fossils from Scotland.

The anatomy of Stratesaurus (Reptilia, Plesiosauria) from the lowermost Jurassic of Somerset, United Kingdom

ABSTRACT We provide a complete description of one of the oldest plesiosaurians, Stratesaurus taylori from the earliest Hettangian of the United Kingdom. At least 25 apomorphies distinguish S. taylori from the sympatric Thalassiodracon hawkinsii, to which all three specimens of S. taylori were originally referred. Several features of the skull of S. taylori suggest specialization on small prey items, or sieve feeding. In particular, it has anteriorly inclined premaxillary and mesial maxillary teeth and an only weakly heterodont maxillary dentition. This indicates niche partitioning among sympatric small-bodied plesiosaurians: T. hawkinsii has a pronouncedly heterodont dentition. With a body length estimated around 2 m, S. taylori is one of the smallest plesiosaurians, comparable to T. hawkinsii. Our anatomical review of S. taylori suggests difficulty determining its precise phylogenetic affinities. This is consistent with a general lack of phylogenetic resolution among earliest Jurassic plesiosaurians, which may result from missing data on their Triassic ancestry. However, due to its plesiomorphic morphology and well-characterized anatomy, we recommend S. taylori as an ingroup representative of Plesiosauria for future cladistic analyses of Triassic sauropterygians.

Three-year evaluation of best practice guidelines for nematode control on commercial sheep farms in the UK

Anthelmintics are commonly used on the majority of UK commercial sheep farms to reduce major economic losses associated with parasitic diseases. With increasing anthelmintic resistance worldwide, several countries have produced evidence-based, best practice guidelines with an example being the UKs Sustainable Control of Parasites in Sheep (SCOPS) initiative. In 2012, a pilot study demonstrated that SCOPS-managed farms used fewer anthelmintic treatments than traditionally managed farms, with no impact on lamb productivity and worm burden. Building on these results, we collected data for three consecutive years (2012-2014) with the following aims: (1) To compare the effects of traditional and SCOPS-based parasite management on lamb productivity and worm burden; (2) To evaluate the effect of region and farm type on lamb productivity and worm burden; (3) To compare the frequency and patterns of use of anthelmintic treatment on traditional and SCOPS-managed farms. The study was carried out on 16 farms located in the North east and the South west of England and Wales. Lamb productivity was assessed by quantifying birth, mid-season and finish weights and calculating daily live-weight gains and time to finish in a cohort of 40-50 lambs on each farm. Five annual faecal egg counts were carried out on each farm to assess worm burden. No differences in lamb productivity and worm burdens were found between farms that adopted SCOPS guidelines and traditional farms across the three years. However, mean infection levels increased for both the SCOPS and the traditional groups. Lamb production was not significantly different for farm type and region but the effect of region on infection was significant. For both ewes and lambs, SCOPS farms carried out significantly fewer anthelmintic treatments per year, and used fewer anthelmintic doses/animal than traditional farms. The data suggest a trend to increasing use of anthelmintics in ewes on traditional but not on the SCOPS farms and a decreasing use of anthelmintics in lambs on both SCOPS and traditional farms. Across time, an increasing number of SCOPS farmers left their ewes and lambs untreated and the reverse was true for traditional farmers. Overall, farms implementing SCOPS guidelines used less anthelmintic treatments and less frequently than traditionally managed farms, without loss of animal performance or increased worm burden. Implementing SCOPS guidelines might have economic benefits for farmers, help reduce development of anthelmintic resistance on farms and decrease any environmental impact of anthelmintics. Furthermore, these data suggest some important epidemiological trends that should be investigated in long-term studies.

Hugh Miller: fossils, landscape and literary geology

The bicentenary of the birth of Hugh Miller (1802–1856) in Cromarty (in northern Scotland) has enabled a reappraisal of this fine spare-time geologist, in turn stonemason and banker, and eventually Edinburgh newspaper editor. In Cromarty he had the usual advantages and limitations of a local collector far from metropolitan centres. But Miller was different from other collectors: he was author of classic books such as The Old Red Sandstone , making famous the Old Red Sandstone fishes and Jurassic marine fossils of the area around Cromarty. Millers ironically titled autobiography My Schools and Schoolmasters recommended geology as an improving recreation. His writings are suffused with the thrill of discovery and the wonder and beauty of fossils, inspiring future geologists such as John Muir (1838–1914), pioneer of environmental conservation, and George Jennings Hinde (1839–1918), microfossil researcher. In his often autobiographical writings Miller made geology an integral part of the world as he saw it: he was not ‘just’ a ‘popularizer’, but (as he always wanted) a literary man in the all-encompassing Victorian manner. Geology merged with local history and folklore — all ‘libraries’ of the past. But his writings remain rooted in insightful observation — as scientist and poet — of specimen and scenery, from microscope slide to landscape, and in careful reconstruction, for instance, of fossil animals from fragmentary remains. When Miller dealt with wider issues of God in creation and the truths of geology, he deployed his fossils, as in Footprints of the Creator (1849) which attacked the reheated Lamarckian evolutionism of Vestiges of the Natural History of Creation (1844). But, contrary to the common misconception that he was driven to suicide by a conflict between science and religion, Miller simply saw these as different facets of the same truth. Indeed, he notably defended geology against religious literalists. Millers fossil collection is now mostly in the National Museums of Scotland, Edinburgh, with some specimens in the new Hugh Miller museum, Cromarty, which derives from that founded by his son, also called Hugh (1850–1896), a professional geologist with the Geological Survey. This appraisal reveals further depths to Hugh Millers appreciation of geological specimens, and to the significance of his surviving collection. Millers relationship with the material world of objects shows remarkable consistency and an unwillingness to compartmentalize: Millers fossils exemplify the deep continuity of his world.

The electrical resistivity of vanadium and vanadium-chromium solid solutions

Abstract The temperature dependence of the electrical resistivity of a number of solid solutions of chromium in vanadium has been measured from 20°K to 293°K. Fine structure is observed in several regions of the resistivity-composition curve. The anomaly in the temperature dependence of the resistivity of pure vanadium has also been found to occur in alloys of up to 25% chromium.