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Science News

112 Posts authored by: John Jackson
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Adrian Pont from Entomology spent two weeks on fieldwork in Armenia, 16-29 July. This was the second of three projected visits to Armenia, within the framework of the International Science and Technology Center project “Molecular genetic monitoring of blood-sucking flies (Diptera) as a basis for biological control of vectors of dangerous infectious diseases and precautions against the acts of biological terrorism”

 

The 2010 fieldwork was in June and the projected 2012 fieldwork will be in May. In this way, the seasonal succession from spring, summer and high summer will have been covered. Samples were collected at 52 sites. 14 of these were during day-trips out from Yerevan to localities previously investigated in 2010, such as Tsakhkadzor at over 2300 m and Lake Kari at nearly 3200 m.  Adrian also spent a morning investigating the polluted River Hrazdan that runs through the centre of Yerevan. The other 40 sites were in the south-east of Armenia.

 

From 22 to 28 July inclusive, Adrian and his team drove to Meghri on the border with Iran and worked their way slowly back to Yerevan. His companions were a mosquito specialist and two blackfly specialists, and consequently the sites visited were sometimes in villages (for adult mosquitoes in cow sheds) but more usually on the banks of rivers and streams (for blackfly larvae and pupae). As it happened, the riverine habitats were the only ones to produce any Diptera as the open grassland was dry and baked in the summer sun. Day temperatures were in the upper 30s, and it was only at the high-altitude localities that Diptera were more abundant. Early morning and evening were the best times of day to collect Diptera.

 

Some 1350 specimens were collected and pinned. Over the next few months those on minutien pins will be mounted, and data labels will be printed and attached to all specimens, which will then be sorted to families.  Adrian will continue sorting and identifying the Muscidae, and Michael Ackland will continue his work with the Anthomyiidae.

 

Among other families, there were few Brachycera and few Acalyptrates. Dolichopodidae were very abundant around the streams, but the season for Empididae was clearly over and very few specimens were found. Sarcophagidae were abundant, but there were few Calliphoridae and only a moderate number of Tachinidae. In the Muscidae, genera such as Thricops, Drymeia, Phaonia, Helina, Mydaea, Coenosia, were also notably scarce or absent. One species (undescribed) of Spilogona was common at Lake Kari. Lispe species and some Limnophora were present at almost all rivers and streams and, as in 2010, Lispe tentaculata was the most abundant and widespread predaceous species of Muscidae and was observed taking adult chironomid midges as prey.

 

In a paper in 2005 (Pont, A.C., Werner, D., and Kachvoryan, E.A., A preliminary list of the Fanniidae and Muscidae (Diptera) of Armenia,  Zoology in the Middle East, 36: 73-86) Adrian noted that only 20 species of Muscidae had previously been recorded from Armenia. The list now stands at well over 100 species, and grows with each field trip.

 

This article was taken from Entom news - thanks to Adrian and Esther for content.

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Entomology Seminar

 

Alfred Russel Wallace in the New World: Wallace's US-Canada Lecture Tour of 1886-87

 

Charles H. Smith

Western Kentucky   University, USA

 

Wednesday September 14th

Neil Chalmers Science Seminar Room (DC.LG16)

 

2 pm - 3 pm

 

Alfred Russel Wallace is best known for events that took place relatively early in his life, in connection with his natural history collecting expeditions to South America and Indonesia in 1848-52 and 1854-62, respectively. But after returning the second time to England he lived another fifty-one yearsto the age of ninety in 1913. This later portion of his life was also filled with activity, and even included another lengthy period of time spent out of the country. Over a ten month period in 1886-87 he toured some ten thousand miles across Canada and the United States, along the way observing, lecturing, botanizing, attending séances, and meeting and befriending a couple of hundred leading figures from American science, politics, and academia, right up to President Grover Cleveland. He left a journal of his tour which is most enlightening, and currently under transcription for publication. In this presentation, focussing on the journal, we attempt a return to this late-Nineteenth Century world.

 

Contact: Dr Vladimir Blagoderov, Entomology (v.blagoderov@nhm.ac.uk)

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Palaeontology Department Seminar

 

Thursday 1st September Neil Chalmers Seminar Room, DC2, 1600

 

Sampling, modelling, and making sense of the fossil record of diversity

 

Dr. Andrew B. Smith, Department of Palaeontology, NHM


While we can sample the available rock record effectively for its fossil content, the record we are sampling is itself biased.  Understanding and quantifying this bias is key to developing better estimates of diversity over time, and various ways of estimating rock record bias have been proposed.  Recent criticisms of these approaches by Benton and co-workers are shown to be misplaced or unfounded.

 

To demonstrate by how much the fossil record is distorted by unavoidable sampling inequality, the diversity of planktonic microfossil clades are estimated from two independent records – that of land-based outcrops and deep-sea cores.  These differ markedly, with each tracking its respective record of rock accessibility over time. However, modelling and subsampling approaches to the two very different records converge on a single underlying pattern, showing that these are powerful approaches for recovering less biased estimates of how past diversity has changed over geological time.

 

Contact: Greg Edgecombe g.edgecombe@nhm.ac.uk

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Biomimetics of Water

Posted by John Jackson Aug 19, 2011

Andrew Parker is a Research Leader in the Crustacea Research Group in the NHM Zoology Department.  He writes:


Animals and plants capture or store water in efficient ways where water is scarce. This research into biomimetics of water has the ultimate aim to manufacture devices that can collect, filter and store water in dry regions of the Earth, which are set to expand rapidly with the progression of climate change.


This work falls into the subject of biomimetics – extracting good design from nature. It involves a collaboration with physicists, chemists, mathematicians and engineers at the Massachusetts Institute of Technology (MIT), which was instigated by National Geographic magazine, who dedicated a feature article to the independent but uniquely related work of the MIT and NHM groups (April 2008).


The subjects we cover are diverse, and include the water collecting mechanisms in various beetles and lizards, hydrophobic and hydrophilic surfaces in plants, and the mechanisms by which diving birds can maintain an air layer beneath their feathers while submerged. Within the physical sciences, we consider the mechanics of flow in fluids, and the interaction of fluids with surfaces, including hydrophobic, hydrophilic and pining behaviours of fluid drops, such as that observed when dew drops cling to certain leaves.


Our research begins with electron microscopy to understand the 3D architecture of the biological surfaces at the micron and nano levels. In other, specialized microscopes, drops of water and other liquids (with different fluidic characteristics) are placed on the biological surfaces and their “contact angles” are measured. This provides data on how well different liquids “ball up”, and therefore the degree of water repellency, for instance. Then, calculations are made to explain how each biological surface is responsible for its precise water properties. From here, new surfaces can be designed to solve precise liquid problems in industry, along with solving water capture problems in hot environments.


The micro-structure I found on the back of a Namibian “darkling” beetle (Stenocara sp.), with combined hydrophobic and hydrophilic surfaces, efficiently captures water from wind-borne fogs. This has been manufactured in plastics for use in air conditioning systems, where it recaptures water leaving the system as vapour, which can be recycled. Further, the hot water vapour no longer contributes to warming the atmosphere.


The overall aim of this research is to produce a prototype device to be employed in developing countries to collect clean water for drinking. This device will feature as many adaptations found in nature as possible, enhanced by the superior materials available in the industrial world.


The device may well contain the Namibian beetle device, since 22 different countries are subjected to desert fogs yet are short of rain. It may draw water from damp soil (rather than from more accessible puddles) in the manner of the Australian “thorny devil” lizard (Moloch horridus) or the xylem system of plants. It may filter water to make it safe for drinking as occurs in the cuticle of certain beetles, self-clean its surface as known in some plant leaves and butterfly wings, and channel and store water efficiently and safely as evident in burrowing desert frogs. Additionally, other biomimetic devices such as “moth-eye antireflectors” and “beetle heat dissipaters”, known to improve solar cell efficiency, will be incorporated where a renewable energy source is required.


Above all, the device must be resilient in the field. To achieve this, we are holding competitions at MIT (in the manner of their famous robotics competition), encouraging students to design the most practical device that may be employed in the Skeleton Coast area of Namibia. This device should showcase several new, bio-inspired technologies that are each ripe for commercialization in disparate industries.


For instance, there may even be spin offs in oil repellent surfaces, and in non-salty water collection for ships and boats at sea. Already, there have been several transatlantic visits between the NHM and MIT, and we have achieved breakthroughs such as understanding the depths to which a bird can dive based on the nanostructure of a single feather.


Most recently we have received vital support from two government ministers in South Africa, so hopefully the politics of employing our devices in Africa will keep pace with our scientific progression, and we can achieve our ultimate goal.

 

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Greg Edgecombe in the Museum's Palaeontology Department has collaborated with Australian colleagues on the investigation of fossil eyes from the early Cambrian period (515 million years ago).  They published their findings in the prestigious journal Nature at the end of June.


The fossils were found in the Emu Bay shale - a very finely grained rock formed from mud - from Kangaroo Island in South Australia.  Shales can preserve fossil organisms in incredible detail, and those from the Cambrian have yielded an amazing diversity of invertebrate animals that lived in marine environments - those of the Burgess Shale in western Canada are probably the best known.  The Cambrian is of particular interest in evolutionary terms because it was a period at which many new groups of organisms are first seen - the term "Cambrian Explosion" is often used to describe the fantastic and rapid diversification of life in a relatively short geological period.


A fair amount is already known about the eyes of trilobites from this period - their eyes were biomineralized (containing minerals) which meant that the fossils are very well preserved.  However, Greg and his colleagues found fossil eyes that do not seem to have been mineralized - much more delicate structures that have only been preserved because of the exceptional nature of the shale fossils.


The eyes appear to be relatively similar to the compound eyes of modern arthropods - they are around 5-7 mm across and contain around 3,000 individual lenses (ommatidia).  The lenses in the centre of the eye are larger, with a falling gradient in size towards the edge of the eye - creating a bright zone for better sight in lower light.  This structure is characteristic of a modern mobile predator such as a robber fly - more advanced than those of trilobites and not seen in other fossils for a further 85 million years. This emphasises the apparent rapidity and complexity of evolution in this early period.

 

robber crop.jpg

The fossil eyes have similar characteristics to those of modern predatory arthropods such as this robber fly

 

However, a puzzle is that the eyes do not seem to be associated with any identifiable organism in the shale, such as Anomalocaris. It seems possible that the eyes may have been shed in moulting, but by which animal remains to be seen.


 

Lee, M. et al. 2011 Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia. Nature 30 June 2011 474 7353 631-634 http://dx.doi.org/10.1038/nature10097

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Thanks to a collaboration between the Tropical Andean Butterfly Diversity Project (TABDP, which is a University College London, NHM and Darwin Initiative project)  and the Butterflies of America project (BoA) , we now have a unique online archive of photographs of the type specimens of Neotropical butterflies - butterflies from the tropical areas of the Americas.

 

 

 

NaturalHistoryMuseum_030980_IA Paplio homerus.jpg

 

This project has a number of purposes and benefits. 

 

  • First, the list of butterflies is a checklist - a list used to define all the species found in a particular area. This is important because it summarises current knowledge of diversity: biodiversity scientists and conservation professionals know what has been found and what they should take account of in research. The act of compiling a checklist will often involve research and reorganisation of collections to reflect current knowledge
  • Second, these are photographs of the type specimens - the definitive reference specimens used as authority for the use of a scientific name.  These are housed in museums such as the NHM in a number of different locations. A virtual photographic collection allows scientists to see easily where the reference specimens are for use - and the photograph may be sufficient for some scientific uses.  It also brings together specimens from different collections that would not otherwise be brought together without considerable cost.
  • Third, the photographs can help in identification and mean that scientists and conservation workers in different parts of the Americas can use the resource as a reference - this may need some care and development of more complex identification resources, such as keys, but the pictures are an important resource nonetheless.


The great majority of these images are scans of print photographs taken by Gerardo Lamas over many years of research in museums throughout the world, and we are very grateful for his generosity in allowing them to be made available. Scanning and initial databasing of the prints was completed by TABDP, supported by the Darwin Initiative, and then given to BoA to be made available online. BoA's Nick Grishin designed and wrote the web pages that now display the images. Numerous other people deserve acknowledgement, including the curators of the museums where these types are housed and many other members of TABDP, BoA and other lepidopterists who contributed images, time and encouragement. 

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This international conference will be held from the 6th-7th December, 2011, on the general theme of South Asian natural history collections with a special emphasis on the collections of the Danish botanist Nathaniel Wallich (1786-1854), a major figure in the history and development of botany in the nineteenth century.

 

As superintendent of the Calcutta Botanic Garden (1817-1846), he undertook botanical expeditions, described new plant species, amassed a large herbarium, collected thousands of plant specimens and commissioned local artists to draw beautiful botanical watercolours. His work has thus been influential in South Asian Natural History research.

 

This conference will explore the challenges associated with exploiting such collections and the interesting opportunities they provide for interdisciplinary research. In particular, the conference will consider the experience of the recent “Wallich and Indian Natural History” project as an interesting exemplar (a collaboration with the British Library and The Royal Botanic Gardens, Kew). An earlier blog post outlined some of the work of this project.

 

Major South Asian natural history collections from the 18th and 19th century are now dispersed across institutions in South Asia, Europe and beyond. Thus, the conference will be hosted by the Natural History Museum, London and the Royal Botanic Gardens, Kew in partnership with the British Library. This conference plays an integral part in the World Collections Programme funded project “Wallich and Indian Natural History”.

 

More information is available on the NHM Centre for Arts and Humanities website. A full programme and travel information will be available on that site by the 30th September, 2011. Abstract Submission Deadline: 30th August, 2011

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Recently, a group of Scientists from the NHM (Shelley Cook, Ralph Harbach, Lorna Culverwell, Erica McAlister, Entomology; and David Bass, Zoology) and a research student from the University of Oxford (Ed Glucksman) joined forces with Unité des Virus Emergents, Marseille, Université de la Méditerranée (Gregory Moureau and Laurence Bichaud) for a cross-disciplinary collecting trip.

 

RH.JPG

 

Ralph apparently playing Crazy Golf, but he and Erica are in fact collecting adults and immatures…..

 

 

The aims of the trip, conceived by Shelley, were threefold; firstly, the Collection of voucher specimens of mosquito species present in the region for morphological and molecular identification work, and for the Collections here at the Museum. Voucher specimens simply means specimens that are collected and kept in collections for reference – in contrast to simply identifying in the field or lab and not keeping them. In total, approximately 100 mosquitoes will be processed for voucher work, which includes both morphological and molecular characterisation, and many more flies will be added as well. The molecular analysis will be for specific DNA sequences that are now widely used in molecular identification – often called DNA barcodes.  These use mitochondrial cytochrome c oxidase subunit I and II (COI and COII sequence).

 

asp.JPG

Preparing to use the aspirator - a device for sucking up insects

 

The second aim was the collection of bulk samples of adult and immature mosquitoes onto dry ice for screening for flaviviruses; 2010 saw the first two cases of dengue fever (caused by a flavivirus) in patients in metropolitan France (near Nice) with no history of travel and whom were most likely to have been infected by mosquitoes from a local population. In total, approximately 2000 samples were plated for later screening. Previous similar studies conducted by our group have shown a prevalence of novel flaviviruses of up to 10%. Any virus positives will be isolated, characterised and sequenced before publication in scientific journals..

 

sc.JPG


Shelley concentrating on numbering samples

 

 

And thirdly, together with David Bass from Zoology, the collection of a range of plant, water and insect specimens were put into liquid nitrogen followed by extraction of small RNA fractions. These will be tested via Illumina sequencing to test whether this method can detect signatures of viral infection and to compare viral biodiversity across a range of environmental samples - including in particular in association with mosquitoes and protists (single-celled organisms).

 

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David wading to collect samples - always that temptation to go a bit deeper than the length of the waders...

 

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Team photograph

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In February 2011, two botanists from the department, Dr Harald Schneider and Dr Cécile Gueidan, participated in a collecting trip in Northern Vietnam. The trip  aimed at enhancing NHM and Vietnamese collections in ferns, lichens and liverworts from this very species rich area of South-East Asia. It was organized by collaborating partners from the Vietnam National Museum of Nature in Hanoi by the botanists Mr Do Van Truong and Mrs Ngan Lu Thi. The team was also joined by Dr Hongmei Liu, who is a botanist from the Fairylake Botanical Garden in Shenzhen, China.

 

lichen1.JPG

 

After arrival, the team visited the Vietnam National Museum of Nature in Hanoi and studied fern specimens kept in the museum’s collection. They also met Prof. Pham Van Luc, the director of the Vietnam National Museum of Nature, and Harald Schneider and Cécile Gueidan presented their research to the Museum staff and students. Most of the three weeks were spent in different protected areas in the North of Vietnam: the Pa Co-Hang Kia Nature Reserve in the extreme West of the Hoa Binh province, the Bac Me Nature Reserve in the South-Eastern part of the Ha Giang province, the Na Hang Nature Reserve in the North of the Tuyen Quang province and the Ba Be National Park in the North- West of the Bac Kan province. Most of the sites visited included tropical forests at different stages of land use, which ranged from almost entirely deforested areas to few relatively untouched patches of primary forest.

 

lichen2.JPG

Left to right: Hongmei Liu, Harald Schneider, Don Van Truong, Ngan Lu Thi and two guides from the Ba Be National Park

 

 

This collecting trip followed a first visit to Vietnam by Harald Schneider in 2010 and had allowed completing previous collections of ferns from this area. For lichens, only few studies had been carried out in this country and rock substrates had almost not been explored. The lichen specimens collected during this fieldtrip will therefore contribute to the knowledge of the poorly studied lichen flora of Vietnam. In total, we collected 283 specimens of ferns (including at least two new records for Vietnam), 26 specimens of leafy liverworts, and about 400 specimens of lichens.

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Archaeopteryx - a bird?

Posted by John Jackson Aug 1, 2011

Archaeopteryx must be one of the most familar images associated with the origins and evolution of birds.  Famously, it was first described one hundred years ago in 1861 from a single feather in 150-million year old Jurasssic limestone from Solnhofen in Bavaria. 

 

NaturalHistoryMuseum_041333_IAblog.jpg


The first skeletal fossil of Archaeopteryx was found in 1861 and purchased by the British Museum (part of which later became the Natural History Museum) for £700 in 1862.  This specimen was described by the then Superintendent of the Museum's Natural History Departments, Richard Owen, in 1863.  A further nine fossils have been found since then and are found in various museums. Although the first fossil found was of a feather, it is not now certain that the feather was from the same species as the body fossils. When first found, Archaeopteryx was uniquely important in showing the connection between birds and other reptiles - but since  then, evidence from many other fossils has supported the scientific view  of the origins of birds.


These fossils have traditionally been seen as those of a very early bird at the very base of the current avian branch of the Tree of Life.  The birds emerged by the evolution and diversification of a group of reptiles in the late Jurassic period - just over 161 million years ago. From a current scientific viewpoint, the basal group of reptiles - the Paraves - split to form two groups: the Avialae (becoming birds over time); and the Deinonychosauria. 


However, a new paper in the journal Nature by Xing Xu et al. has involved examination of a newly discovered fossil species from this group, Xiaotingia, from China.  This organism was very similar to Archaeopteryx and the question arose of whether Archaeopteryx should be placed in the Avialae or the Deinonychosauria: which branch? Systematic scientific investigation of several Archaeopteryx fossils, Xiaotingia, and other fossils, suggests initially that Achaeopteryx does not fall into the same group as the birds - the Avialae. This involved examination of the NHM Archaeopteryx, illustrating the importance of collections as a continuing reference resource for science.


The research suggests that Archaeopteryx is not an ancestral bird in the Avialae, but should instead be seen as a member of the Deinonychosauria, along with Xiaotingia.  This finding will cause considerable controversy in science as results are scrutinised and discussed and further evidence amassed.  Future fossil findings will add further data that may add detail and support for different positions, but reference to the original fossils will continue to be essential.  One point of interest will be that the characteristic feathers and skeleton of Archaeopteryx show that this character combination may not have been restricted to birds alone, but seems to have been found in a wider group of reptiles.

 

Witmer L M Palaeontology: An icon knocked from its perch Nature 475, 458–459 (28 July 2011) doi:10.1038/475458a Published online 27 July 2011


Xing Xu,Hailu You,Kai Du & Fenglu Han An Archaeopteryx-like theropod from China and the origin of Avialae Nature 475, 465–470 (28 July 2011) doi:10.1038/nature10288 Published online 27 July 2011




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An interdisciplinary team of Museum mineralogists and zoologists,  with external collaborators, have been looking at the impacts of nano  particles on the environment for some years.  Silver nanoparticles  (AgNPs) are widely used in industry for manufactured goods and this may result in environmental impacts, notably within aquatic ecosystems. Silver can be toxic to living organisms when they are exposed to it by selected routes and in particular forms.  It's important that in pursuing the positive benefits of NPs, we are able to understand and avoid the negative impacts.

 

Scientists have over many years developed understanding of which substances are toxic, and why.  Sometimes this knowledge will have come about as a result of seeing the effects of unintended exposure to humans in factories or accidentally contaminated food. Exposure to toxic substances can result in death or very serious health effects to humans or other organisms.  However, we have a lot to learn - much of our understanding has arisen from particular cases or studies and one area of particular complexity is exposure through the environment.

 

We are exposed to a whole range of chemical substances in our environment, often at very low levels of concentration and sometimes over many years.  The same is true of other organisms - although the effects of particular substances will be different for different species, as a result of their different genetic makeup, diet, habitat and other factors.  Further, exposure to different combinations of chemical substances can lead to the toxic effect of a particular substance being decreased or increased in a particular and often unexpected way.

 

The use of nanoparticles has increased tremendously in recent years in industry.  Nanoparticles are very tiny particles of a substance - less than 100 nanometres in all three dimensions (one nanometre is one billionth of a metre).  This size means that they can have different chemical, physical and biological properties from larger particles, and this includes their toxic effects.

 

The study looked at estuaries, which are complex environments and often the site of human industrial developments.  Sediments in estuaries are sinks for numerous pollutants, but also habitat and food for deposit feeders (eating the sediments) such as the polychaete worm Nereis diversicolor.

 

Ingested sediments were investigated as an important route of uptake for NPs. The Museum scientists looked at N. diversicolor that had eaten sediment contaminated with either citrate-capped AgNPs (30 +/- 5 nm) or aqueous silver for 10 days. The experimental results indicate separate routes for silver to enter the cells of the worms and differing final locations of Ag delivered in dissolved and NP form.

 

N div1.jpg

 

For AgNPs an endocytotic pathway appears to be a key route of cellular uptake - endocytosis means that the NPs are ingested by the cells of the organism, engulfing the NPs into a vacuole within the cell, in contrast to the usual cross-membrane transport of dissolved substances.

 

All these findings lead to a better understanding of how organisms respond, interact and deal with NPs - this is complex and will have a substantial influence on toxic effects and environmental impact.


GARCIA-ALONSO J, KHAN F R, MISRA S K, Turmaine M, SMITH B D, RAINBOW P S, LUOMA S N, VALSAMI-JONES E 2011. Cellular internalization of silver nanoparticles in gut epithelia of the Estuarine Polychaete Nereis diversicolor. Environmental Science and Technology 45: 4630-4636.

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There is considerable international interest in the impacts of invasive species on biodiversity.  Species are described as being invasive when they cause impacts on biodiversity outside their normal range as a result of introduction or spread as a consequence of human activity.  This impact can lead to loss of native species, spread of disease, impacts on native habitats or other effects.  They are often described as invasive alien species. In the marine environment this can happen as a result of transport by ships in ballast water, or migration through new sea routes such as the Suez Canal.


Recent work from the Museum provides more evidence that the flood of invasive Red Sea species entering the Mediterranean via the Suez Canal includes fish parasites.  Dr Hoda El-Rashidy (who obtained her PhD while researching in the Zoology Department at the NHM) and Prof Geoff Boxshall (Zoology) have described two more new species of parasitic copepods from Egyptian Mediterranean waters off the coast of Alexandria.

 

Their hosts, two species of Red Sea rabbitfish (Siganus luridus and S. rivulatus) have established populations in the Mediterranean. Invasive species often leave their parasites behind, due to the sampling effect of passing through a small founder population, but the continuing discovery of invasive parasitic copepods combined with the absence of any genetic evidence of a bottleneck in their host populations, highlights the remarkable scale of the faunal invasion of the eastern Mediterranean.

 

International concern and efforts to monitor and control impacts of invasive species are significant, with an EU Strategy,  a major focus from the Convention on Biological Diversity, and a UK Non-Native Species Secretariat.  Even on a city level here in London there is coordination on selected species such as Japanese knotweed and various invasive crayfish.


El-Rashidy, H.H. & Boxshall, G.A.  2011. Two new species of Parasitic Copepods (Crustacea) on two immigrant fishes from the Red Sea of Family Siganidae. Systematic Parasitology 19: 175-193. DOI 10.1007/s11230-011-9298-7


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Fin loss in a spiny eel

Posted by John Jackson Jul 19, 2011

Vertebrates - mammals, birds, fish and amphibians - have broadly the same body plan with two pairs of limbs.  However, over time, some species and groups have lost one or both pairs of limbs.  Many others have reduced limbs.  Whales, snakes, caeclian amphibians and a range of fish are some of the examples.

 

Modern scientific research has a strong interest both in the patterns of development and in how and why these change as a result of genetic evolution - it does appear that different genes can be involved in limb reduction and loss in different groups. 

 

Drs Ralf Britz and Lukas Rüber (NHM Zoology) and colleagues from University College London and the South African Institute for Aquatic Biodiversity, Grahamstown reported the first case of pectoral fin loss in the Mastacembelidae (Teleostei: Synbranchiformes) with the discovery of a new species of spiny eel from Lake Tanganyika in the Journal of Zoology.

 

A previous evolutionary phylogeny of mastacembelids using comparisons of genetic differences between different species,  coauthored by Dr Rüber , had placed the new species Mastacembelus apectoralis sp. nov. within the Lake Tanganyikan species flock, having diverged from its sister species M. micropectus around 4.5 million years ago. M. micropectus also shows a reduction in the size of its pectoral fin and endoskeletal girdle, and has largely cartilaginous pectoral radials and a reduced number of pectoral-fin rays. This is in contrast to the bony skeletons of most fish species in this group

 

The loss of pectoral fins and reduction of associated girdle elements in M. apectoralis represent another independent occurrence of this evolutionary phenomenon within teleosts. The discovery of this species highlights the exceptional diversity of the biodiversity hotspot, Lake Tanganyika, the understanding of which is of critical importance with the pressures of pollution, overfishing and climate change threatening the speciose and evolutionarily significant diversity of this ancient lake.


Brown, K. J., Britz, R., Bills R., Rüber, L. & Day J. J. (2011). Pectoral fin loss in the Mastacembelidae: a new species from Lake Tanganyika. Journal of Zoology April 2011 doi:10.1111/j.1469-7998.2011.00804.x

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Sir Joseph Banks

Posted by John Jackson Jul 13, 2011
Not really news, but just for interest - up in the top of the galleries is this statue of Sir Joseph Banks by Francis Chantrey, and given by his friends to the British Museum (see also the print in the BM).  Our latin is not quite good enough to attempt a translation, but the inscription is below for the enthusiasts.


IMG_0993.jpg

JOSEPHVS.BANKS.BARONETTVS

QVI

QVAM.VNIVERSAE.RERVM.NATVRAE.SCIENTIAM

PER.MARE.PER.TERRAS

APVD.VLTIMAS.GENTES

BARBARAS.ETIAM.INCOGNITAS.PERPETIENDO

IN.ANNIS.IVVENILIBUS.CONQVISIVERAT

EANDEM

IN.PATRIAM.REDVX

ET.SOCIETATIS.REGIAE.APVD.LONDINIENSES.PRAESES

CVNCTIS.SVFFRAGIIS.FACTVS

PER.RELIQVAM.VITAM.SVMMA.IPSE.CVM.DILIGENIA.COLVIT

ET.SINGVLARI.SVA.LIBERALITATE.AC.MVNIFICENTIA

AEMVLO.ALIORVM.PATROCINIO

POVENDAM.AMPLIANDAM.HONESTANDAM.PROPOSVII

AMICI

VIRTVTIS.EIVS.MEMORES

IMAGINEM.EX.COLLATIONE.DEDICAVERVNT

ET.MVSEI.BRITANNICI.IN.ORNAMENTVM

DONO.DEDERVNT

VIXIT.ANNOS.LXXVI.MENSES.VI.DIES.VI

DECESSIT.XIII.KAL IVL.A.S.M.DCCC.XX

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Darwin's Corals

Posted by John Jackson Jun 27, 2011

Brian Rosen (Zoology) and Jill Darrell (Palaeontology) have just published a paper on Darwin’s coral specimen collections and specimen lists. Darwin examined coral reefs in detail during the voyage of HMS Beagle, describing the different types of reef and using this information to write one of his early scientific works The Structure and Distribution of Coral Reefs

 

They were invited to present a talk on this subject at a conference on Darwin’s work at the Universita G. d’Annunzio, Chieti-Pescara, in November 2009. The paper deals with the only known Darwin geological collection in the Museum that comprises 29 coral reef specimens (held in Zoology), almost all from Cocos (Keeling) atoll in the Indian Ocean and accompanied by a little known and hitherto enigmatic Coral Reef Specimen List (holograph held in the NHM Library). Darwin mentions his visit to Keeling and interest in corals in a letter to his sister, sent from Mauritius.

 

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Darwin distinguished three primary types of reef: atolls, barrier reefs and fringing reefs, and used his own observations and those from FitzRoy's surveys to explain what he thought were the reasons for the existence of atolls - including Keeling, which he examined in detail.  Darwin noticed that reef-building corals did not grow below a certain depth of water, but that atolls isolated from other rocky islands were reasonably common.  He rejected the idea that gradual sediment buildup had provided foundations, and said that the idea of so many isolated sea-mounts of the right depth in the middle ocean for coral growth could be rejected.  He argued that rocky islands had sunk gradually below the surface, leaving their original coral reefs to keep the same level as the surface of the sea.  Darwin thought that earthquakes might be connected with the sinking islands - he did not know then what we know about plate tectonics, but had developed a keen interest in geological uplift and subsidence in South America on an earlier part of the voyage.

 

Brian and Jill offer for the first time a plausible explanation of the true origin and purpose of this list and set of specimens.  The specimens are unusual, if not unique, in being a small exhibit prepared by Darwin himself, at or before the time he donated them. The most likely occasion for which Darwin prepared his exhibit was that of his first presentation of his famous subsidence theory of coral reefs to the Geological Society of London on May 31st 1837.

 

Rosen B. R & Darrell, J. 2011. A generalized historical trajectory for Charles Darwin’s specimen collections, with a case study of his coral reef specimen list in the Natural History Museum, London. In:  Stoppa, Francesco & Veraldi, Roberto, Eds., Darwin tra scienza, storia e società. 150° anniversario della publicazione di Origine delle Specie [= Darwin in science, history and society. 150th anniversary of the Origin of Species.]  Edizioni Universitairie Romane, Roma, pp.133-198.

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