Saturday 30 June 2012

Namibian Fairy Circles.

Fairy rings are known from many parts of the world. They consist of a ring on grassy ground inside which the grass is stunted, but with particularly lush grass around the perimeter. The rings start small and grow over time, eventually spreading out so much they are lost into the landscape, with the grass recovering in the centre. At certain times of year mushrooms can be seen growing in the lush grass, which reveals the cause of the rings; fungal colonies spreading out from the point where the first spore landed, draining nutrients from within the ring and carrying the to the spreading edge, where the growing fungus uses them, and the grasses mop up the excess.

The arid grasslands of the Namib Desert have a similar phenomenon, dubbed 'Fairy Circles' to emphasize their similarity. Like Fairly Rings, Fairy Circles contain an area of stunted, or more often dead, grass, surrounded by a ring of more luxurious grass, but unlike Fairy Rings they do not appear to grow, appearing fully grown, persisting for some years then vanishing again. The cause of Fairy Circles remains obscure; no microbiological or chemical differences between the soil inside and outside the rings has been found. Grasses placed in open bottomed pots within the circles wilt and die, but those in closed pots are unaffected. The Circles are found in grasslands on the fringes of desserts throughout Namibia, from the borders of Angola in the north to the South African border in the south; it is likely that they extend into other countries, but do not seem to have been studied outside Namibia. They are larger in the north, reaching 10 m in diameter near the Angolan border, but seldom exceeding 2 m near the South African border.

In a paper published in the journal PLoS One on 27 June 2012, Walter Tschinkel of the Department of Biological Science at Florida State University, conducts a review of our knowledge of Fairy Circles, and adds data from a number of new sources.

A Namibian Fairy Circle. Tschinkel (2012).

Tschinkel used data from Google Earth, satellite photography obtained from Digital Globe Imaging, areal photographs from Namib Sky Balloon Safaris and ground data gathered in the Namib Rand Nature Reserve. He found that the Circles took about five years to form; during with time the grass sickened and died across the whole of the interior at a more-or-less even rate, the Circles did not in any way grow like a fairy ring. Once formed the Circles lasted on average for about 40 years then were recolonized by grasses. It was possible to detect the location of former Circles because the wind would hollow out sand from the middle of the grass-free Circles, creating a depression. Sometimes these old Circles would come back to 'life' forming 'Lazarus Circles', but this was rare. The Circles would sometimes 'grow' by the formation of a new part-Circle at the edge of a current Circle, though this appeared to be a new Circle forming partially overlapping the old. Circles could sometimes be detected in areas with very sparse grass coverage.

Tschinkel does not offer any explanation for the Circles, but was able to rule out some previously offered ones. The most obvious explanation is a fungal or other microbial agent, as with Fairy Rings, but the growth pattern does not match this and no such agent could be found. Another popular explanation is a chemical agent, such as fumes from a subterranean hydrothermal seep, though again no such agent could be found. It has been suggested that the activities of ground-dwelling Termites might be responsible, but no connection between the Circles and Termites has been found.

Google Earth image of an area of Fairy Circles. Tschinkel (2012).

See also The oldest animals - Pre-Ediacaran Sponges from Namibia(?)Mysterious object falls from the sky in Namibia and Snowfall in Namibia

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Friday 29 June 2012

Two new views of τ Boötis b.

τ Boötis is a binary star system roughly 50 light years from Earth in the constellation of Boötis; the system (or more accurately its primary star) is naked-eye visible from Earth on a dark night. The primary star (τ Boötis A) is a Yellow-White K-type dwarf star with 1.3 time the mass of the Sun and an effective surface temperature of 6360 K (compared to 5778 K for our Sun). This is orbited by a Red Dwarf companion (τ Boötis B) with a mass 40% of the Sun's at a distance of 240 AU (i.e. 240 times the average distance between the Earth and the Sun. In 1997 a Hot-Jupiter type planet was discovered orbiting τ Boötis A every 3.3 days at a distance of 0.0481 AU; this planet was named τ Boötis b.

The position of τ Boötis (here written as Tau Bootis) in the constellation of Boötes.

τ Boötis b does not transit (pass in front of) τ Boötis A when seen from Earth; it was detected by the tiny wobble that its gravity causes in the motion of the star. This means that only a rough estimation of the planets mass could be made, and nothing determined about its atmospheric chemistry. However techniques in planetary science have moved on since the 1990s, and it is now in theory possible to undertake a spectrographic analysis of the atmosphere of a non-transiting planet, and to determine some of the other properties of such a planet by measuring the Doppler Shifting of these spectra, particularly that produced by the gas Carbon Monoxide. on 27 June 2012 two papers were published on the online arXiv database at Cornell University Library detailing different analyses of data on the τ Boötis System obtained by the Very Large Telescope, located at the European Southern Observatory on Cerro Paranal, Chile.

In the first of these papers a team of scientists lead by Matteo Brogi of the Leiden Observatory at Leiden University, conclude that the orbit of τ Boötis b is inclined at an angle of 44.5° relative to the Earth, and that the planet has a mass 5.95 times that of Jupiter. They also conclude that the atmosphere of τ Boötis b lacks a thermal inversion; that is to say it cools steadily at higher altitudes rather than having cloud-trapping warmer and cooler layers as on Earth. Such thermal inversions have been detected on other Hot-Jupiter type planets; Brogi et al. theorize that τ Boötis b may have lost the heat absorbing compounds (such as water and methane) that cause such inversions due to high levels of ultra-violet irradiation from τ Boötis A.

Schematic representation of the orbit of τ Boötis b about τ Boötis A. The arrow points towards Earth. The star and the orbit are to scare; the planet has been magnified ×3 for clarity. Brogi et al. (2012).

In the second paper Florian RodlerMercedes Lopez-Morales and Ignasi Ribas, of the Institut de Ciències de l’Espai at the Universitat Autònoma de Barcelona, conclude that the orbit of τ Boötis b is inclined at an angle of 47° relative to the Earth, and that the planet has a mass 5.6 times that of Jupiter. They furthermore conclude the atmosphere has an average temperature in excess of 1800 K (compared to 287.2 K for Earth or 735 K for Venus).

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Thursday 28 June 2012

The Kandyan House Gecko; not extinct after all.

In 1853 Lieutenant Colonel Edward Frederick Kelaart (1819-1860) of the Ceylon Medical Service published a study of the fauna of Sri Lanka entitled Prodromus fauna Zeylanica,  in which he described (amongst other things) a description of a House Gecko from Kandy in the centre of the island, the ancient royal capitol, which he named Hemidactylus pieresii. For almost 160 years no more was heard of H. pieresii, and scientists have assumed the species to be lost.

In a paper published in the journal Zootaxa on 28 June 2012, Sudesh Batuwita of the Institute of Fundamental Studies and the Wildlife Conservation Society Biodiversity Research and Education Center at Hiyare Reservoir and Rohan Pethiyagoda of the Australian Museum, announce the rediscovery of Hemidactylus pieresii, during a study of the island's snakes and lizards commissioned by the Wildlife Heritage Trust of Sri Lanka

Batuwita & Pethiyagoda found the Geckos at Kandy and a number of other sights in the southeast of the island. They conclude that the species has not been missing, but rather has been widely identified as the closely related H. depressus.

Preserved specimen of Hemidactylus pieresii, the Kandyan House Gecko. Batuwita & Pethiyagoda (2012).

Hemidactylus depressus in lifeBatuwita & Pethiyagoda (2012). 

Map of Sri Lanka showing the original location where Hemidactylus pieresii was discovered (red square), the new locations where Hemidactylus pieresii was found (black squares) and the locations where Hemidactylus depressus was found. Batuwita & Pethiyagoda (2012).

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Possible volcanic activity on Mount Siple, Antarctica.

Mount Siple is one of the world's most remote volcanoes, located on Siple Island, off the coast of Marie Byrd Land, Antarctica. It is a shield volcano (volcano with a fairly flat profile made up mostly of layers of lava) 3110 m in height, and thought to be quite young (less than 10 000 years), though its geology has not been well studied due to its remote location. It's topography has only ever been recorded by sketch map, and if the summit has ever been climbed, then the event has never been recorded.

Areal photograph of Mount Siple. Smithsonian Global Volcanism Program/US Navy.

On 20 June 2012 the European Metop Satellite detected an apparent volcanic plume issuing from Mount Siple; the Metop Satellite does not produce visual images, so it is not completely certain this is what it was seeing. The satellite witnessed temperatures on Mount Siple rise to a balmy -22 ℃, against a background temperature of -28 ℃, and produced infrared imagery of what appeared to be a plume of steam with a temperature of -55 ℃ at its base.

Mount Siple, and the other volcanoes of Marie Byrd Land, are located on the western margins on the  West Antarctic Rift System, which appears to be slowly splitting Antarctica in two in a similar way to the Great Rift Valley in Africa (though the geology of the region is not nearly as well studied). Marie Byrd Land is apparently starting to pull away from the rest of the continent, and between the two regions an area of rifting has developed, with upwellings of magma feeding volcanism in Marie Byrd Land and the Transantarctic Mountains.

Map showing the extent of the West Antarctic Rift System. Abbreviations: AR, Ames Range; BSB, Byrd Subglacial Basin; BST, Bentley Subglacial Trough; CM, Crary Mountains; ECR, Executive Committee Range; FR, Flood Range; MM, Mount Murphy; MS, Mount Siple; MT, Mount Takahe; TM, Toney Mountain. Paulsen & Wilson (2010).

Simplified diagram showing the evolution from a Rift Valley to a full Ocean Basin, using the African Rift Valley, the Red Sea and the Atlantic Ocean as examples. This is essentially the same process as that which is starting along the West Antarctic Rift. Hannes Grobe, Alfred Wegener Institute for Polar and Marine Research/Wikipedia

Wednesday 27 June 2012

Pollen from potshards, and what it can tell us about the ancient climate of northwest China.

Pollen is extremely useful to archaeologists and palaeontologists. It is resilient both and distinctive, and plants produce it in large amounts, and scatter it freely in the environment. Scientists who study pollen, called palynologists, are able to use pollen to date ancient sediments and to reconstruct the vegetation, and therefore climate, of ancient sites. Recently archaeologists have discovered pollen can be extracted from some ancient pottery, if this was incompletely fired, i.e. not fired at a high temperature or for a long period of time.

In a paper published in the journal PLoS One on 25 June 2012, a team of scientists led by Yi-Feng Yao of the State Key Laboratory of Systematic and Evolutionary Botany at the Institute of Botany at the Chinese Academy of Sciences, describe the recovery of pollen from potshards from the Yanghai Tombs of Turpan in Xinjiang Province, western China, and the implications for the climate in the time when the tombs were excavated.

The Yaghai Tombs are located in the Flaming Mountains in eastern Xinjiang province, and are between 2000 and 3000 years old. The area is now extremely arid, with settled farming populations inhabiting scattered oases. However at the time the tombs were dug it is thought the area had a more temperate climate. 

The location of the Yanghai Tombs. (A) Map showing the location of Xinjiang Province in China. (B) Map showing the location of the Flaming Mountains within Xinjiang Province. (C) Satellite Image of the Flaming Mountains and surrounding area, showing the location of the Yanghai Tombs. Yao et al. (2012).

The Yanghai Tombs were laid down by by the Subeixi Culture, and contain large amounts of pottery, as well as other goods. They have provided useful botanical material previously, in the form of plant materials buried as grave goods. This has been fairly well publicized due to the large amount of cannabis present, but also included food crops such as grapes, melons, apricots etc.

Pottery goods from the Yanghai Tombs. (1) Single-handled jar with waves. (2) Single-handled pot with folded lines. (3) Single-handled cup with arcuate sculpture. (4) Single-handled cup with whirlpools. (5) Single-handled jar. (6) Single-handled jar with reticulations. (7) Single-handled jar with triangles. (8) Single-handled pot with serrate patterns. (9) Single-handled cup with flame-like patterns. (10) Single-handled jar with waves. (11) Pottery basin. (12) Pottery bowl with four legs. Photographed by Yong-Bing Zhang. Yao et al. (2012).

Yao et al. extracted pollen from potshards (broken pottery) from two tombs at Yanghai, both roughly 2700 years old. The pottery from the first tomb appeared to have been fired at to high a temperature for to long for much pollen to have been preserved, however a good amount of pollen was recovered from pottery from the second tomb. The first tomb yielded pollen from Wormwood, Lilies, Elms, Buckwheat, Legumes, Mulberries and grasses, the second pollen from Clubmoss, Ephedra, Artemesia, Elms, Goosefoot, Asters, Beeches and Gentians, with Goosefoot and Elm being the most abundant.

By combining the data from the pollen with that from the previously gathered plant remains, Yao et al. were able to make an interpretation of the vegetative cover at Yanghai 2700 years ago. They conclude that the overall climate of the Flaming Mountains was still arid in this period, but that the tombs were dug close to a marshy oasis surrounded by grasslands and coniferous woodland.

See also The origin of domestic dogsDating the Chauvet Cave artWhat Nitrogen tells us about the diet of MammothsWhat a 4.6 million-year-old Three Toed Horse can tell us about the climate of Mid Pliocene Tibet and Trying to find Peking Man.

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Monday 25 June 2012

The death of Lonesome George and the extinction of the Pinta Island Giant Tortoise.

On 24 June 2012 Edwin Naula of the Galápagos National Park announced the death of a Giant Tortoise named Lonesome George at the Charles Darwin Research Station on Santa Cruz Island. Lonesome George had been a resident of the Station since 1972, after it was discovered that his native habitat on the remote, volcanic, Pinta Island had been devastated by introduced feral goats.

Lonesome George. Galápagos National Park.

Lonesome George was almost certainly the last member of his species, the Pinta Island Giant Tortoise, Chelonoidis nigra abingdoni, (there is another male Tortoise rumored to be a member of the species in Prague Zoo, but this animal has never been formally described in any scientific publication), meaning that his death comes the extinction of the species. The Charles Darwin Research Station had made several attempts to mate Lonesome George with females of the closely related Isobella Island Tortoise, Chelonoidis nigra becki, but this had failed to produce viable eggs (note: technically Chelonoidis nigra abingdoni and Chelonoidis nigra becki are subspecies, but most biologists define species as reproductively isolated units, which would seem to apply here). This was combined with the clearing of feral goats from Pinta Island, with a view to re-introducing the (hybrid) tortoises; it is likely that the Island will now be re-populated by Tortoises from elsewhere in the Galapagos. 

The Galapagos Islands have (or had) a distinctive fauna of Tortoises, with many islands, and some regions on larger islands, having evolved their own distinctive strains of Tortoise adapted to local conditions. When Charles Darwin visited the Galapagos in 1835 the Vice Governor of the islands, Nicholas Lawson, boasted of being able to tell what island a tortoise originated from at a glance. 

Scientists currently recognize twelve different varieties of Galapagos Tortoise, all currently classified as subspecies of a single species, Chelonoidis nigra. The Pinta Island Tortoise is the second of these to go completely extinct, after the Charles Island Tortoise, Chelonoidis nigra nigra, with the Duncan Island Tortoise, Chelonoidis nigra duncanensis, also extinct in the wild. In addition the Hood Island Tortoise, Chelonoidis nigra hoodensis, is considered Critically Endangered under the terms of the IUCN Red List of Threatened Species, with another four strains being considered Endangered, and the remainder Vulnerable.

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The peculiar planets of Kepler-36.

The Kepler Space Telescope has been staring constantly at the same part of the Galaxy for over three years, looking for the tell-tale dimming and wobbling of stars that reveals the presence of planets around them. During this time it has discovered a number of remarkable planetary systems that have revolutionized our thinking on how such systems form and evolve.

In a paper published on the online arXiv database at Cornell University Library on 20 June 2012, and in the journal Science on 21 June 2012, a team of scientists led by Joshua Carter of the Harvard-Smithsonian Center for Astrophysics announce the discovery of a new, and rather remarkable, planetary system named as Kepler-36.

The system's star, Kepler-36A, is an essentially sun-like star that has reached the subgiant stage of its life; it is coming to the end of its hydrogen supply and starting to fuse helium. This generates more heat than hydrogen, causing the star to expand. Kepler-36A has 1.071 times the mass of the Sun, and an effective surface temperature of 5911 K (compared to 5778 K for our Sun).

This is orbited at a distance of 0.115 AU (i.e 11.5% of the distance between the Earth and the Sun) every 13.8 days, by Kepler-36b, a super-Earth type planet with a mass 4.45 times that of the Earth, thought to be most likely composed largely of rock and water, and at 0.128 AU every 16.2 days by Kepler-36c, a mini-Neptune type planet with a mass 8.08 times that of the Earth, thought to be composed largely of gaseous hydrogen and helium. 

The orbits of these two planets are remarkably close together, closer than any pair of planets previously discovered, separated by just 0.013 AU (1.945 milion km), so that at their closest the two planets are only five times as far apart as the Earth and the Moon, at which distance Kepler-36c would be 2.5 times as large in the sky of Kepler-36b as the full moon is in the sky of Earth.

An artist's impression of how Kepler-36c would appear from Kepler-36c at the closest point in the two planets' orbits. Harvard-Smithsonian Center for Astrophysics/David Aguilar.

As well as being remarkably close, the two planets are remarkably different in composition. In our Solar System there is a clear differentiation between rocky and gaseous planets, with the former confined to the inner part of the system and the later to the outer parts. This is thought to be a result of the way in which the Solar System formed, with volatile gasses largely driven out of the inner system by the heat of the early Sun. Since we have begun studying other planetary systems, we have come to understand that this is not always the case, with many systems having large gaseous planets close to their stars. Scientists believe such planets are likely to have formed further out in their systems, then migrated inwards as friction with material in the protoplanetary disks slowed them down in their orbits. However this is the first time we have seen a rocky and a gaseous planet in such close proximity, and modeling the formation of the Kepler-36 system is difficult based upon our current understanding of the formation of planetary systems.

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Sunday 24 June 2012

Earthquake in southwest China.

On Sunday 24 June 2012 slightly before 4.00 pm local time (slightly before 8.00 am, GMT) an Earthquake hit southwest China in the border region between Sichuan and Yunnan States, roughly 53 km west of Qiaowa in Sichuan. This was recorded by the United States Geological Survey as measuring 5.5 on the Richter Scale and occurring at a depth of 9.3 km, and by the World Data Center for Seismology in Beijing as 5.7 on the Richter Scale at a depth of 11 km. The area is remote and mountainous, so the extent of the damage and casualties is unclear, but at the time of writing three people are reported dead in Ninglang County in Yunnan and one in Yanyuan County in Sichuan. Over a hundred more are reported to have been injured, 20 seriously, but these figures are likely to rise.

Map showing the location of the 24 June quake. USGS.

The southwest of China is fairly prone to Earthquakes, being effected by the impact of the Indian Plate into the Eurasian Plate from the south. Most of the Earth's convergent plate boundaries are between continental and oceanic plates, with the oceanic plate being subducted beneath the continental, or between two oceanic plates, where one is subducted beneath the other. In South Asia two continental plates are colliding; neither of these readily subducts beneath the other, so a crumple zone has formed along the margin of the two plates, forming the Himalayas, the Tibetan Plateau and the mountain ranges of Central Asia. This is far from being a smooth process, and Earthquakes are common across the region.

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New species of Pipewort from Brazil.

Pipeworts (Eriocaulaceae) are herbaceous plants related to Grasses, Sedges and Rushes. They are found throughout the world, but are most abundant in the American tropics. They favor moist or wet soils and occasionally grow in shallow water.

In a paper published in the journal Phytotaxa on 4 January 2012, Nancy Hensold of the Department of Botany at the The Field Museum of Natural History in Chicago, Adriana Luiza Oliveira of Pós Graduação em Ciências Biológicas (Botânica) at Museu Nacional/UFRJ and Ana Maria Giulietti of Pós Graduação em Botânica at the Departamento de Ciências Biológicas at the Universidade Estadual de Feira de Santana describe a new species of Pipewort from coastal broadleaf forests (restingas) in Bahia and Rio de Janeiro States, Brazil.

Map of coastal southern Brazil, showing the locations where the new plant was discovered. Hensold et al. (2012).

The new species is placed in the genus Syngonanthus, and given the specific name restingensis, referring to the environment in which it was found. It is a 10-20 cm grassy plant growing in clumps, with erect inflorescences bering rosettes of cream coloured flowers. Synogonanthus restingensis is also capable of reproducing viviparously, with new plants forming on the tips of the inflorescences, which then bend over to touch the ground; this is a habit seen in other members of the Eriocaulaceae, but not otherwise in the genus Syngonanthus

Syngonanthus restingensis (drawn Renato Moraes). (A) Habit. (B) Detail of leaf apex with hydathode. (C) Mature capitulum showing vivipary. (D) Young capitulum. (E) Involucral bract. (F) Floral bract. (G) Staminate flower. (H) Pistillate flower, with one sepal removed. (I) Gynoecium. Hensold et al. (2012).

Syngonanthus restingensis was found growing in rivulets seasonally flooded sand-dunes and sphagnum mats (sphagnum is type of moss which forms floating mats) in herbaceous or open shrubby restinga at three sites in southern Bahia and Rio de Janeiro States. Two of these sites have subsequently been developed, making it likely that S. restingensis has gone locally extinct, but the third is in the Parque Nacional da Restinga de Jurubatiba in Rio de Janeiro, where the plant can still be observed growing. Because it is found in a limited number of sites in coastal forests highly prone to development, S. restingensis is considered to be Endangered according to IUCN Red List Criteria.

Syngonanthus restingensis. (A) Population at flowering. (B) Detail of habitat showing population on Sphagnum turf. (C) Inflorescences showing early vegetative proliferation (D) Senescent scapes bearing pseudoviviparous rosettes. (E) SEM image of seed. (F) Detail of (E) showing appressed pseudotrichomes. (Photos A–C by Marcelo Fraga Castilhori. Photo D by Adriana Oliveira. Photos E–F by Amanda Veiga). Hensold et al. (2012).

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Earthquake shakes the Kamchatka Peninsula.

On Sunday 24 June 2012, at 4.15 pm local time (3.15 am GMT) the east coast of the Kamchatka Peninisula in the Russian Far East was shaken by an Earthquake measured by the United States Geological Survey as measuring 6.1 on the Richter Scale and occurring roughly 150 km north of the fishing port of Ust-Kamchatsk at a depth of 17.4 km. Such a large quake at such a shallow depth has the potential to cause considerable damage, but the remoteness of the location means this one is unlikely to have caused anyone serious harm.

Map showing the location of the 24 June quake. USGS.

The Kamchatka Peninsula is (mostly) located on the northeastern part of the Okhotsk Plate, which also underlies the northern part of Japan and part of the Russian state of Magadan. This is bounded to the east by the Pacific and Bering Sea Plates, both of which are being subducted beneath the Kamchatka Peninsula, which is in effect an island arc attached to the mainland. As the plates are subducted they are  partially melted by the friction and the heat of the Earth's interior, forming liquid magma which then rises up through the overlying Okhotsk Plate, feeding the volcanoes of the Kamchatka Peninsula. The subduction is not a smooth process, the plates stick together for periods causing build-ups of pressure. They then break apart in sudden movements causing Earthquakes such at this one.

Map showing the Okhotsk Plate and the tectonic plates surrounding it. Wikipedia.

There are 160 volcanoes on the Kamchatka Peninsula, 29 of which are active, including Klyuchevskaya Sopka, the highest active volcano in Eurasia at 4750 m. These were made a UNESCO World Heritage Site in 1996, in recognition of the areas outstanding geological and biological uniqueness. 

A volcanic plume rises above Kluchevskaya Sopka. The Moscow Times.

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Police seize Dinosaur from New York warehouse.

Authorities in New York have seized the bones of a 7.3 m Tarbosaurus bataar (a Late Cretaceous Theropod Dinosaur closely related to Tyranosaurus rex), from a storage facility belonging to Cadogan Tate Fine Art in Queens, New York. The skeleton was sold for US$1.05 million on 20 May 2012 by Texas-based Heritage Auctions, to an undisclosed buyer, thought to be a private New York museum, but authorities in Mongolia are demanding their return as stolen antiquities.

The feet of the Tarbosaurus specimen in the Cadogen Tate warehouse. U.S. Immigration and Customs Enforcement.

The fossil was sold by Florida-based Eric Prokopi who imported them from the UK in March 2010, on papers which described them as 'reptile bones' valued at US$1500. Prokopi claims that the bones originate from outside Mongolia, and that he and his wife spent much of the last year carefully preparing and mounting them. However experts, including Mark Norell of the American Museum of Natural History, have identified them as belonging to a known specimen from Ömnögovi Province in Monglolia, identified in 1946 by a joint Soviet-Mongolian expedition to the Gobi Desert but never excavated. The bones were last seen in the desert in 1995, and were found to be missing in 2005. Norell also pointed out that very few Tarbosaurus specimens have ever been found outside of Mongolia, and that those have all come from China, where restrictions on excavating and exporting Dinosaur remains are even tighter.

The smuggling of antiquities is a major international crime, and while it is more typically associated with archaeological remains, dinosaur (and other large vertebrate) fossils can have a substantial value and are a significant part of this trade. The US is a common destination for smuggled antiquities, and has been accused in the past of not doing enough to protect the heritage of other countries, though on this occasion the Mongolian authorities are said to be very pleased with the promptness of US action. The UK is also often sighted as a country that does not do enough about antiquities smuggling, with many stolen artifacts allegedly being routed through London. It is unclear if the Tarbosaurus remains seized in New York were ever actually in the UK, or what steps (if any) British authorities are taking to investigate this. 

See also LH PV18, a New Mini-Tyranosaur, or an Immature Tarbosaur? and Dinosaurs on Sciency thoughts YouTube.

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Saturday 23 June 2012

A Brittle Star from the Late Jurassic of Southern Germany.

Brittle Stars (Ophiuroids) are Echinoderms superficially resembling Starfish, with five arms arranged radially around a central hub that contains the mouth and other organs, but structurally somewhat different. The arms of Starfish are essentially rigid, with the animal relying on tube feet on its underside to move it about. In Brittle Stars the arms are articulated and used for locomotion, the tube feet are still present, but used primarily for food gathering. The group have a long fossil record, first appearing in the Early Ordovician about 500 million years ago,  but they are seldom abundant in the fossil record, probably because their remains are easily disarticulated (brittle) and therefore do not enter the fossil record in large numbers. Most modern Brittle Stars are deepwater dwellers, but in the past shallow water forms appear to have been more common.

In a forthcoming paper in the journal Acta Palaeontologica PolonicaBen Thuy of the Department of Geobiology at the Geoscience Institute at the University of Göttingen and Hartmut Schulz of the Paleobiology Work Group at the Department of Geosciences at the University of Tübingen redescribe a Brittle Star from the Late Jurassic of Steinenfeld in southern Germany, first described by the nineteenth century German Palaeontologist Friedrich August von Quenstedt in 1876.

Quenstedt originally described the Brittle Star under the name Ophiurites crinitus, however the genus name Ophiurites is now considered invalid, so Thuy and Schulz place it in the new genus Ophiosternle, from 'stern' the Swabian (southern German) for 'star'. It shows close affinities to a number of modern, deepwater Brittle Stars, but the deposits in which it was discovered are interpreted as having originated on a shallow, storm disturbed, coral reef, suggesting that the move into deepwater has happened since the Jurassic. There are a number of other known Brittle Star fossils from the Late Jurassic of southern Germany and France, most of which are from fine-grained mudstones (i.e. low energy environments). Brittle Stars may have been an abundant part of the fauna of Jurassic reefs, but their poor preservational potential in this environment would hide this from us.

Ophiosternle crinitus, complete specimen in dorsal view. Scale bar is 5 mm. Thuy & Schulz (2012).

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2012 LZ1; bigger than we thought.

On 14 June 2012 the newly discovered asteroid 2012 LZ1 flew past the Earth at a distance of 5.3 million km (roughly 14 times as distant as the Moon). The asteroid had only been discovered four days earlier, and was estimated to be 500 km across, enough to cause quite a bang if it hit us, though this was never thought likely to happen.

The asteroid was on a course quite close to ours, so that it stayed in range of Earth-based telescopes for some time; this was not an opportunity to be wasted, and 2012 LZ1 was closely watched from a number of centers around the globe. One of these centers was the Planetary Radar System at the Arecibo Observatory, in Puerto Rico, which scanned 2012 LZ1 in some detail as it withdrew from the Earth.

Radar image of 2012 LZ1 produced by the Arecibo Observatory.

The results of this study came as a shock; 2012 LZ1 was twice as large as originally thought, 1 km across rather than 500 m; this may not sound like a lot, but for a roughly spherical object is 33.5 times the volume, which adds up to rather a lot of rock. Such a rock hitting the Earth could have serious global effects, so having a close encounter with one with only four days notice is fairly alarming.

The subject of objects from space impacting on the Earth is a controversial one. Everybody agrees that a significantly large object hitting the Earth is likely to have serious consequences, but scientists differ in their views on the extent to which this happens. Planetary scientists, who look for evidence that the Earth's history may have been influenced by such impacts find plenty of evidence for this, however geologists, who try to find the causes of events on Earth, find no proof that impacts have caused these events. While it is quite likely that large impacts do happen on Earth, and do have widespread consequences, we do not have examples of events where the most likely cause was extra-terrestrial. For example, the extinction event at the end of the Cretaceous could have been caused by a large object impacting the Yucatan Peninsula in Mexico, it is far more likely to have been caused by an outpouring of flood basalts in India called the Deccan Traps.

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Friday 22 June 2012

Earthquake in New South Wales.

On Friday 22 June 2012 at a little after 7.15 pm local time (a little after 9.15 am GMT) an Earthquake shook occurred New South Wales, centered roughly 110 km north of Canberra and 200 km west of Sidney and at a depth of about 10 km, according to Geoscience Australia, who measured the quake as 3.8 on the Richter Scale. Such a quake could potentially have been felt over a fairly large area, but is unlikely to have caused any significant damage or casualties.

Map showing the location of the 22 June quake. USGS.

Australia is probably the least Earthquake-prone of Earth's continents, since none of the margins of the tectonic plate on which the continent sits comes close to the continental landmass, but still suffers the occasional quake. The southeast of the continent is affected to some extent by spreading on the margin between the Antarctic and Australian Plates far to the south, and movement on the margin between the Australian and Pacific Plates to the southeast; this is both a subduction zone and a transform margin, the Pacific Plate is being subducted beneath the Australian Plate, and at the same time the Australian Plate is rotating relative to the Pacific Plate, pushed by the movement on the Antarctic Plate margin. The area has seen two larger quakes this week, in Victoria on Tuesday 19 June and on Macquarie Island earlier on 22 June, and it is likely that this quake is an aftereffect of one or both of those larger quakes.

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Blue Flatworms invade Menorca.

Land Planarians of the family Geoplanidae (Flatworms) are simple animals; they have a rudimentary nervous system, lack a through gut (so that they must regurgitate any waste products), and have no respiratory organs (they absorb oxygen through their moist, non-watertight skins, but cannot actively collect it, meaning they can never dry out and cannot grow very large). Nevertheless they can be voracious predators of other invertebrates, and can be very harmful when they are introduced to ecosystems where the local invertebrate fauna is unfamiliar with them. This is particularly true on small islands where invertebrate faunas are often highly endemic, and low in numbers; such populations can be quickly overwhelmed by exotic predators.

In a paper published in the journal Zookeys on 4 June 2012 a team of scientists led by Karin Breugelmans of the Royal Belgian Institute of Natural Sciences discuss the discovery of some exotic blue Flatworms from an orchard at Ciutadella de Menorca on the easternmost Balearic island of Menorca, and the implications of that discovery.

Map showing the location of Menorca. Breugelmans et al. (2012).

Breuglemans et al. carried out DNA analysis of the worms in order to find out their species and determine that they were invaders, and not a previously undescribed part of the local fauna. This revealed the worms to be members of the species Caenoplana coerulea, a highly invasive Flatworm native to eastern Australia, which has previously been introduced to New Zealand, the United States, the United Kingdom, Norfolk Island, France, and Argentina and mainland Spain. This species has proved particularly problematic in North America; it was first recorded in California in 1943 and had reached Florida by 1961.

Caenoplana coerulea from Menorca. Breugelmans et al. (2012).

The first specimens of Caenoplana coerulea were collected from the orchard in 2009. In 2011 it was also found in a nearby garden. The likely impact of Caenoplana coerulea on the invertebrate fauna of Menorca is hard to assess, but in other places it has proved very hard to eradicate once established due to its broad diet; it will predate a variety of invertebrate groups including earthworms, snails, insects, isopods and millipedes. 

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Earthquake shakes Macquarie Island.

Slightly after 3.30 pm local time (slightly after 4.30 am GMT) on Friday 22 June 2012, Macquarie Island in the southwest Pacific Ocean was shaken by an Earthquake measured by the United States Geological Survey as 6.0 on the Richter Scale, at a depth of 9.9 km, 24 km northwest of the Island. This is a fairly large quake at quite a shallow depth; in an inhabited region it could be devastating, but on Macquarie Island, uninhabited except for a few scientists at the Australian Antarctic Division's  Macquarie Island Station (and a lot of penguins), it is unlikely to have caused any serious harm.

The location of the Macquarie Island Quake. The large landmass at the top right is South Island, New Zealand. The red lines are the boundaries between tectonic plates. USGS.

Macquarie Island is located on the boundary between the Pacific and Australian Plates. This is a convergent margin, where the Pacific Plate is being subducted beneath the Australian. This causes uplift in the overlying Australian Plate, which has lifted Macquarie Island above the waves. This is usually accompanied by some degree of vulcanism, but this does not seem to be the case on Macquarie Island, to date at least. This makes the geology of the island rather unique, it is formed from basaltic seafloor, but has been exposed above the sea surface for between 80 000 and 700 000 years, during which time it has been exposed to constant erosion from the wind and storms of the Southern Ocean, but never actually glaciated. Due to its unique geology Macquarie Island was declared a World Heritage Site by UNESCO in 1997.

Macquarie Island; Macquarie Island Station in the foreground. IPS - Radio and Space Services.

The process of subduction is not a smooth one, the tectonic plates frequently stick together only to break apart again as the pressure builds up. This causes frequent Earthquakes in subduction zones, including Macquarie Island. In December 2004 the Island was subject to an Earthquake measuring 8.1 on the Richter Scale, one of the largest ever recorded instrumentally.

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Thursday 21 June 2012

A predatory Archosaur from the Late Triassic of southern Poland.

Archosaurs are the group of Vertebrates that include Crocodilians, Dinosaurs and their relatives (and possibly the Pterosaurs; experts differ on whether or not these were Archosaurs). There were a number of different groups in the Triassic, but later in the Mesozoic most of these had disappeared, leaving only the familiar groups.

In a paper published in the journal Acta Palaeontologica Polonica on 16 August 2011 Grzegorz Niedźweidzki of the Institute of Zoology at the University of Warsaw and the Department of Organismal Biology and the Evolutionary Biology Centre at Uppsala University, Tomasz Sulej of the Institute of Paleobiology at the Polish Academy of Sciences and Jerzy Dzik of the Institute of Paleobiology at the Polish Academy of Sciences and the Institute of Zoology at the University of Warsaw describe a new predatory Archosaur from Late Triassic mudstone in the Lipie Śląskie clay−pit, about 2 km west of Lubliniec in Silesia, Poland.

The new Archosaur is described as Smok wawelski, 'Smok' is Polish for 'Dragon' and Smok Wawelski translates as the Dragon of Wawel Hill, a legendary dragon that lived on Wawel Hill in what is now Kraków and which was supposedly slain by Prince Krakus, the founder of the city.

Smok wawelski is interpreted as a 5-6 m predatory, bipedal animal with a 50-60 cm skull. This makes it potentially the largest predatory Archosaur from the Late Triassic; both the Theropod Dinosaurs and the Crocodilians were to produce far larger predators, but this was yet to come. The precise affinities of Smok wawelski are not determined in this paper, as the animal will the subject of a more detailed study by Grzegorz Niedźweidzki as the subject of his Ph.D. thesis. There are a number of trackways in the vicinity which appear to have been left by a large bipedal animal and may be attributed to Smok wawelski.

Skeletal reconstruction of Smok wawelski. Niedźweidzki et al. (2011).

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A Hatchet Wasp preserved in Tertiary amber from Mexico.

Hatchet Wasps (Evaniidae) are solitary parasitic Wasps targeting the eggs of Cockroaches. Cockroaches lay their eggs in cases called oothecae which can contain upwards of 40 eggs, Hatchet Wasps lay their eggs inside these cases and the larvae emerge and consume the eggs (strictly speaking this is carnivorey, since the Wasp larvae are external to the eggs, but Hatchet Wasps are closely related to true parasitic Wasps, are presumed to have evolved from such, so they are generally referred to as part of the wider group 'Parasitic Wasps').

The group have a good fossil record, with many excellent specimens preserved in amber. The oldest known specimens are from the Late Jurassic, and the group appears to have undergone a significant evolutionary radiation in the Cretaceous. However the Tertiary fossil record is not so good, making the precise origin of modern genera unclear.

In a paper published in the journal Zootaxa on 18 June 2012, John Jennings of the Australian Centre for Evolutionary Biology and Biodiversity and the School of Earth and Environmental Sciences at the University of Adelaide, Lars Krogmann of the Entomology Department of the Stuttgart State Museum of Natural History and Steven Mew of the School of Earth and Environmental Sciences at The University of Adelaide describe Hatchet Wasp preserved in amber from a mine near Simojovel in  Chiapas State, Mexico.

The precise age of the specimen is unclear, since the sediments that produced it are marine and the ambers there thought to be reworked, but it is thought to be Late Oligocene or Early Miocene in age, or possibly a little older.

The specimen is placed in the extant genus Hyptia, and given the specific name deansi, in honor of Andy Deans of North Carolina State University, an expert on the Evaniidae. The only known specimen of Hyptia deansi is a 5.55 mm female wasp, though Jennings et al. note that there are a considerable number of undescribed insects in Mexican amber in collections around the world.

Hypatia deansi. (1) Left lateral view. (2) Right lateral view. Scale bars are 1 mm. Jennings et al. (2012).

See also Three new species of Braconid Wasps from the Late Cretaceous of Magadan Province in the Russian Far EastThree new species of Braconid Wasp from PeruAn Eocene False Scorpion from Baltic amber and Evidence of fungal parasites modifying the behavior of ants from the Eocene Messel Shale.

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