Wednesday 31 October 2012

The fate of the Sleeping Dragon.

In October 2004 Xing Xu of the Institute of Vertebrate Paleontology & Paleoanthropology at the Chinese Academy of Sciences and Mark Norell of the American Museum of Natural History published a paper in the journal Nature describing a remarkable Early Cretaceous Troodontid Dinosaur, preserved in volcanic ash in what appears to be a sleeping position. The Dinosaur was named Mei long, meaning Sleeping Dragon. It was a 53 cm long animal, preserved with its tail wrapped around it, and its head tucked under one forelimb, in a manner reminiscent of a sleeping Bird.

Mei long, the Sleeping Dragon. Abbreviations: (cev) cervical vertebrae; (cv) caudal vertebrae; (dv) dorsal vertebrae; (fu) furcula; (lac) left astragalus–calcaneum; (lc) left coracoid; (lf) left femur; (lh) left humerus; (li) left ilium; (lm) left manus; (lp) left pubis; (lpe) left pes; (lr) left radius; (ls) left scapula; (lt) left tibia; (lu) left ulna; (pg) pelvic girdle; (rac) right astragalus–calcaneum; (rc) right coracoid; (rf) right femur; (rh) right humerus; (ri) right ilium; (rm) right manus; (rp) right pubis; (rpe) right pes; (rr) right radius; (rs) right scapula; (ru) right ulna; (sk) skull. Scale bar equals 2 cm. Xu & Norell (2004).

A similar position had previously been observed in another small Troodontid, Sinornithoides youngi (Young's Chinese birdy-thing), described in October 1993 by Dale Russell of the North Carolina Museum of Earth Sciences, and Zhi-Ming Dong of the Institute of Vertebrate Paleontology & Paleoanthropology at the Chinese Academy of Sciences, in a paper in the Canadian Journal of Earth Sciences, though this specimen was less complete, making the diagnosis of the 'roosting position' less obvious. Like Mei long this specimen had been buried in this position, this time in wind-blown sand.

Computed tomography scan image of Sinornithoides youngi. D'Urso, Thompson & Earwaker (2000).

In a paper published in the journal Paleobiology in March 2007, Cynthia Marshall Faux of the Department of Paleontology at the Museum of the Rockies and Kevin Padian of the Department of Integrative Biology and Museum of Paleontology at the University of California, Berkeley disputed the sleeping analysis of Mei long and Sinornithoides youngi, suggesting that their position might instead be a reflexive position caused by reflexive curving of the spine due to muscle spasming during asphyxiation, rather than a sleeping pose.

In a paper published in the journal PLoS One on 27 September 2012, a team of scientists led by Chunling Gao of the Dalian Natural History Museum describe the discovery of a second specimen of Mei long, preserved like the first in an apparent roosting position, and discuss the implications of this study.

The new Mei long specimen. Abbreviations: (aofe) antorbital fenestra; (c) cervical vertebra(e) unnumbered; (c6) sixth cervical vertebra; (c7) seventh cervical vertebra; (ca1–ca18) caudal vertebrae (one through eighteen); (co) coracoid; (d) dentary; (dv) dorsal vertebra(e); (f) frontal; (fm) femur; (fl) fibula; (h) humerus; (il) ilium; (l) lacrimal; (mt-II, mt-III), second metatarsal, third metatarsal etc.; (mx) maxilla; (mxfl?) maxillary fenestra; (n?) nasal; (nc) neural canal; (ns) neural spine; (o) orbit; (p) parietal; (pu) pubis; (pmx) premaxilla; (q) quadrate; (r) radius; (s1, s2, etc.) first sacral vertebra, second sacral vertebra etc.; (sa) surangular; (sc) scapula; (sp) fused neural spine of sacrum; (t) tibia; (u?) possible manual ungual; (ul) ulna; (II-2) second phalanx of digit II of pes; (II-3) third phalanx of digit II of pes; (III-1) first phalanx of digit III of pes; (IV-1–
IV-4) first through fourth phalanges of digit IV. Scale bar equals 1 cm. Gao et al. (2012).

Gao et al. observe that in human victims of asphyxiation the fingers are commonly found in a contorted position, and since three specimens of Troodontid Dinosaurs have now been found in an identical position, none of which show any sign of contorted digits, that it is reasonable to assume that the death position of the dinosaurs was not a result of asphyxiation. They do not, however rule out asphyxiation as a cause of death, observing that a number of bodies recovered from Pompeii appear to be sleeping peacefully, from which they conclude it may be possible to asphyxiate in a deep sleep without undergoing reflexive muscle contortions. They suggest that since the Dinosaurs were killed in a way that did not disturb them from their sleeping position (which would certainly be the case if they were interred by a volcanic lahar or similar) then they may have died within burrows, enabling the bodies to be preserved without exposure to weathering elements or the activities of scavengers.

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To cull or not to cull? The Goliath Grouper in Floridan waters.

The Goliath Grouper is a large (up to 2.5 m and 363 kg) predatory reef Fish, formerly found in coastal waters from Florida to Brazil in the west Atlantic and Caribbean and from Senegal to Congo in the East Atlantic, but which has become extinct, or close to extinct, over much of this range due to overfishing. The species has been protected in US waters since 1990, and appears to have made a good recovery, though populations have not yet reached historical records. However this recovery has coincided with a decline in stocks of commercially important Spiny Lobsters (Panulirus argus) and Grey Snappers (Lutjanus griseus), as well as some other Snapper species, leading many commercial fishers to call for a cull of the Groupers.

A breeding aggregation of Goliath Groupers off Jupiter, Florida. Walt Stearns in Frias-Torres (2012).

In a paper published in the journal Orynx on 21 October 2012, Sarah Frias-Torres of the Ocean Research & Conservation Association examines the cases for and against the culling of the Goliath Grouper in Floridan waters, utilizing evidence from the National Marine Fisheries Service, the Florida
Fish and Wildlife Conservation Commission and the REEF Environmental Education Foundation to assess the vulnerabilities of the Fish and its likely impact on Floridan ecosystems.

Frias-Torres found that the Goliath Grouper is exceptionally vulnerable to overfishing, being large, long lived (possibly over 40 years), slow breeding (fish do not breed till they are at least eight years old), having high site fidelity and forming large, easily visible breeding aggregations. She also noted that the decline in Lobster and Snapper stocks began when the Grouper population was in sharp decline, and continued while the Fish were more-or-less extinct, suggesting that the decline in these species numbers was independent of the Grouper population.

Next Frias-Torres looked at the diet of the Groupers. She found that the Groupers did eat Lobsters, but as part of a varied diet that included other invertebrates, including some that themselves ate Lobsters (such as Crabs and Octopus), as well as a variety of large, slow-breeding poisonous Fish (Goliath Groupers appear to specialize in eating poisonous and venomous Fish, a diet that most other animals shun), many of which also consume Lobsters. It was therefore far from clear what impact culling the Groupers would have on the Lobsters; potentially it could trigger an explosion in the populations of some poisonous Lobster-eating Fish with no other predators, impacting the Lobsters badly. Frias-Torres could not find any evidence that the Groupers ate Snappers at all. 

Finally Frias-Torres examined the potential benefits of having the Groupers in Floridan reef ecosystems. She notes that the Fish are large, attractive animals that are naturally curious about divers, and that similar Fish in other parts of the world have proved highly lucrative fro SCUBA-diving ecotourism if managed well. The high site-fidelity of the fish means that commercial diving companies can more-or-less guarantee an encounter with Goliath Groupers, and the Fish's curious disposition makes a friendly reception likely.

In addition Floridan Reef ecosystems have been invaded by Indo-Pacific Red Lionfish (Pterois volitans/Pterois miles, Scorpaenidae) in recent years. These are voracious predator of native juvenile reef fishes and invertebrates, making them potentially extremely destructive to reef ecosystems. They are also spiny and highly venomous, and therefore have few natural predators. The preference for consuming venomous Fish seen in the Goliath Grouper makes this species an excellent potential natural control of the Lionfish, though the Grouper has not to-date been observed consuming the invasive Fish (this is not altogether surprising, as most studies of the Grouper's diet were carried out before 1990, when it was possible to study the stomach contents of commercially caught Fish; modern studies using non-invasive methods are underway, however).

Red Lionfish, Pterois volitans. Eat The Invaders.

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Earthquake under Lake Baikal.

On Tuesday 30 October, slightly after 6.10 pm local time (slightly after 10.10 am, GMT), a magnitude 4.5 Earthquake occurred 17.9 km beneath Lake Baikal in Siberia, according to the United States Geological Survey. This is large enough that it was probably felt in the area, but probably not to cause any problems, and no damage or injuries have been reported.

Composite satellite image showing the position of the 30 October Earthquake and of Lake Baikal. Google Maps.

Lake Baikal is the oldest and deepest freshwater lake in the world, over 1637 m deep and 400 km long and having formed 20-25 million years ago it is a biodiversity hotspot, hosting amongst other things the world's only freshwater Seal. The depth and longevity of this lake is due to its unique geology (most lakes are just large depressions filled with water); Lake Baikal is part of a forming rift system, with the potential to eventually split the great continent of Eurasia in two (not all rift systems live up to this potential, many stall, and either stop growing or close again). The rift extends southwest from the Lake, forming the Tunka Basin of Siberia. The rift is growing at a rate of about 4.5 mm per year around the lake, and 6.3 mm per year in the Tunka Basin. This has lead to some large Earthquakes on the system, including a Magnitude 9 quake in August 1959, which displaced the bottom of the lake by up to 20 meters.

If the Baikal Rift system continues to open it will eventually grow into a continent-spanning rift like the Great Rift Valley of Africa, then a narrow ocean like the Red Sea, and eventually a fully mature ocean like the Atlantic. 

Simple diagrammatic representation of rifting on the Baikal Basin. Krylov et al. (1993)/Technische Universität Bergakademie Freiberg.

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Tuesday 30 October 2012

The first Arthropod?

The Arthropods are one of the most abundant and diverse groups of animals alive today, and the fossil record suggests this has been the case for most of the last 500 million years. However the origin of the group remains obscure. There are a wide variety of Arthropods in early Cambrian faunas, though these are strange, unfamiliar forms, as well as members of groups thought to be related but outside the group, such as the Lobopodians and Anomalocarians, but the precise nature of the earliest Arthropods is still highly debatable.

In a paper published in the Proceedings of the Royal Society Series B: Biological Sciences on 10 October 2012, David Legg of the Department of Earth Sciences and Engineering at Imperial College London and the Department of Earth Sciences at the The Natural History MuseumMark Sutton of the Department of Earth Sciences and Engineering at Imperial College London, Gregory Edgecombe of the Department of Earth Sciences at the The Natural History Museum and Jean-Bernard Caron of the Department of Natural History (Palaeobiology Section) at the Royal Ontario Museum and the Department of Ecology and Evolutionary Biology at the University of Toronto describe a new fossil from the Burgess Shale Lagerstätten (rich fossil find) in British Columbia which they believe may illustrate the form of the earliest Arthropods.

The new fossil is named Nereocaris exilis, where Nereocaris  means 'Nereo's crab' (Nereo was a Titan, form Greek mythology, often depicted with a fish's tail), and exilis means slender. It is a member of a group known as the 'Bivalved Arthropods', which have bilaterally flattened, elongate bodies with their limbs held within the valves. 

Nereocaris exilis is a 142 mm Bivalved Arthropod with stalked lateral eyes and a single rod-shaped median eye; a bivalved carapace with a postero-dorsal keel; the limbs are entirely encased within this carapace. Behind the carapace is an elongate, tail-like abdomen, composed of about 60 ring-like segments, terminated by a telsion (final group of segments, with small median and elongate lateral processes.

Reconstruction of Nereocaris exilis. Legg et al. (2012).

Based upon their interpretation of Nereocaris, Legg et al. have created a cladistic analysis (family tree, but with maths) of the earliest Arthropods, and the order in which they gained the features typical of the group. Working on the assumption that the Anomalocarians are outside the true Arthropods, this suggests that Nereocaris is the most primitive arthropod yet discovered.

Cladistic reconstruction of the origin of the Arthropods, based upon the accumulation of typical Arthropod features. (1) Development of compound eyes (some groups have subsequently lost, and even re-evolved these). (2) Appearance of Arthropod-like jointed limbs. (3) Appearance of such limbs on the trunk, Branched limbs appear on the trunk, segmented, mineralized exoskeleton. (4) Specialized cephalic (head) appendages. (5) Development of distinct dorsal and ventral sides to the body segments (as opposed to the simple ring-like segments that had occurred before). (6) Reduction in number and greater specialization of the limbs. (7) Modification of appendages into distinct antennae. (8) Appearance of mandibles capable of 'chewing' food. Legg et al. (2012).

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A new Pterosaur from the Early Cretaceous Jiufotang Formation of Liaoning Province in northwest China.

The Pterosaurs were an extinct group of flying Reptiles that existed from the late Triassic to the end of the Cretaceous Period (210 to 65.5 million years ago). They are thought to have been warm blooded, as  many specimens have been found that appear to have had fury skins. Their wings were flaps of skin membrane, similar to that of Bats, supported by elongated fourth fingers and attached to the flanks of the body and legs. Unlike Birds they appear to have been capable of flying before reaching their full adult size, and appear to have taken several years to reach maturity.

In a paper published in the journal Naturwissenschaften on 22 February 2012, Xiaolin Wang of the Key Laboratory of Evolutionary Systematics of Vertebrates at the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of SciencesAlexander Kellner of the Laboratory of Systematics and Taphonomy of Fossil Vertebrates at the Department of Geology and Paleontology at the Museu Nacional Universidade Federal do Rio de Janeiro, and Shunxing Jiang & Xin Cheng of the Key Laboratory of Evolutionary Systematics of Vertebrates at the Institute of Vertebrate Paleontology and Paleoanthropology  and the Graduate University of Chinese Academy of Sciences describe a new species of Pterosaur from the Early Cretaceous Jiufotang Formation of Liaoning Province in northwest China.

The new fossil is named Guidraco venator, where Guidraco means 'ghost-dragon' and venator means 'hunter'. The species is named on the basis of a complete skull and part of the neck. The skull is 380 mm in length, with 54% of this length (205 mm) comprising the rostrum (snout). The specimen has large, overlapping, conical teeth, of a type generally associated with the consumption of Fish, an interpretation supported by the presence of a number of copralites (fossil droppings) packed with Fish-bones; though it is of course not possible to determine if Guidraco venator was responsible for these droppings. There is also a distinctive crest on the top of the skull.

(Top) Photograph of Guidraco venator. (Middle) Interpretive drawing based upon photograph. (Bottom) Reconstruction based upon interpretive drawing. All scale bars 5 mm. Abreviations: (copr) coprolite; (pla) plant; (afo) adductor fossa; (ang) angular; (art) articular; (ax) axis; (cv) cervical vertebra; (d) dentary; (f) frontal; (fcr) frontal crest; (fola) foramen lacrimale; (fopn)
foramen pneumaticum; (hy) hyoid bone; (j) jugal; (la) lacrimal; (ltf) lower temporal fenestra; (m) maxilla; (n) nasal; (naof) nasoantorbital fenestra; (op) opisthotic; (p) partietal; (par) prearticular; (pl) palatine; (pm) premaxilla; (po) postorbital; (pref) prefrontal; (ptf) posttemoral fenestra; (pty) pterygoid; (q) quadrate; (qj) quadratojugal; (san) surangular; (scl) slerotic ring; (soc) supraoccipital; (sor) supraorbital; (spl) splenial; (sq) squamosal; (utf) upper temporal fenestra; (l) left; (r) right; (?) uncertain element. Wang et al. (2012)

Wang et al. suggest that Guidrago venator is closely related to Luddodactylus sibbicki, a Pterosaur from the Lower Cretaceous Crato Formation of Ceará, Brazil, suggesting that there may have been a conection between the two areas in the Early Cretaceous.

Luddodactylus sibbicki, from the Lower Cretaceous Crato Formation of Brazil. Frey, Martill and Buchy (2003)/Reptile Evolution.

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Monday 29 October 2012

Small Earthquake on the Isle of Mull.

On Saturday 27 October 2012, slightly after 6.05 pm British Summertime (slightly after 5.05 pm, GMT) the British Geological Survey recorded a Magnitude 1.1 Earthquake at a depth of 4 km on the Isle of Mull, to thenorth of Loch Scridain. This is a small quake which is highly unlikely to have caused an damage or casualties, and may not have been felt at all - or if it was felt may not have been recognised as a quake.

Map showing the location of the 27 October 2012 quake. Google Maps.

As a rough rule of thumb Earthquakes become more common in the UK as you travel north and west, making the west coast of Scotland the most quake-prone part of the country. The precise cause of Earthquakes in Scotland is not always easy to to determine, as the country is not obviously influenced by any single overiding tectonic feature, but rather by a number of smaller sources of stress, with most quakes being the result of a combination of more than one of these.

Scotland, along with the rest of Eurasia, is being pushed to the east by the expansion of the Atlantic Ocean and to the north by the impact of Africa into Europe from the south. There are also lesser areas of spreading beneath the North Sea, the Rhine Valley and the Bay of Biscay, all of which have an impact on Scottish geology. Finaly there is glacial rebound; until about 10 000 years ago much of the north of the UK was covered by a thick layer of ice, which pushed the rocks of the lithosphere down into the underlying mantle. This ice is now gone, and the rocks are slowly sprining back into position, causing the occasional Earthquake in the process.

Witness reports of Earthquakes can help geologists to understand these events, and the rock formations that cause them. If you felt this quake, or if you were in the area and did not (which is also useful information) then you can report it to the British Geological Survey here.

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Sunday 28 October 2012

Hurricane Sandy heads towards east coast of America.

Hurricane Sandy crossed the Caribbean last week leaving at least 21 people dead, in Jamaica, Haiti, Cuba and the Bahamas. It was thought likely to make landfall in the US this weekend, hitting the coast of either Florida or South Carolina, but instead veered to the east, before moving northward again. It is now thought that it will hit the US coast on Monday 29 October, somewhere between Washington DC and New York. The storm is currently classed as a Category 1 Hurricane, which implies a storm with sustained winds in excess of 119 km/h, but this does not do justice to the scale of the storm, which is several hundred km across and moving slowly northward; a hurricane can have fast winds yet still move slowly as these winds are circular, moving about the centre of the storm. Slow moving storms are more dangerous as they expose any given area to the effects of the hurricane for longer.

Map showing the predicted path of Hurricane Sandy. The blue area is the margin of error; it stops at the Canadian border, but the hurricane is unlikely to. Red areas are likely to suffer flooding. Google Crisismap.

Sandy is being described as the biggest storm ever to hit the United States, which may-or-may-not be hyperbole, but certainly has the potential to be extremely destructive, as it seems inevitable that it will hit northern cities that are not as well prepared for hurricanes as their southern counterparts. Whilst the high winds associated with hurricanes are extremely dangerous, the real danger from such storms is  the flooding. Each millibar drop in air pressure can lead to a 1 cm rise in sea level, and large hurricanes can be accompanied by storm surges several meters high. This tends to be accompanied by high levels of rainfall, caused by water picked up by the storm while still at sea. Due to this the authorities along much of the US eastern seaboard are trying to organize evacuations of low-lying coastal areas, with mixed results in states that are unused to hurricanes.

Hurricane Sandy has already caused both candidates in the US presidential election to adjust their schedules, and may yet have a more profound, long term effect on US politics. It seems inevitable that the storm will be extremely destructive, possibly more so than any event the United States has previously encountered, and rebuilding after such an event is likely to prove a challenge (though not one beyond the means of the nation). This exceptional size and behavior of Sandy has widely been attributed to global warming, which, coming at the end of a season of extreme weather events, may make this more of an issue in future American elections than has been the case to date.

Hurricanes, and tropical storms in general, form due to heating of air over the sea in tropical zones. As the air is heated the the air pressure drops and the air rises, causing new air to rush in from outside the forming storm zone. If this zone is sufficiently large, then it will be influenced by the Coriolis Effect, which loosely speaking means the winds closer to the equator will be faster than those further away, causing the storm to rotate, clockwise in the northern hemisphere and anticlockwise in the southern hemisphere.

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New species of Bush Cricket from the Eastern Carpathian Mountains.

Bush Crickets, or Katydids, are large Insects in the Order Tettigoniidae, related to Grasshoppers and True Crickets. The are distributed widely around the globe, but reach their maximum diversity in the tropics and in temperate North America. The males of each species attract their mates with a distinctive call, made by rubbing stridulatory files on the back of their wings together, something they have apparently been doing since at least the Jurassic.

In a paper published in the journal Zootaxa on 18 October 2012, Gergely Szövényi of the Department of Systematic Zoology & Ecology at Eötvös Loránd University, Gellért Puskás of the Department of Zoology at the Hungarian Natural History Museum and Kerill Márk Orci of the Ecology Research Group of the Hungarian Academy of Sciences, Eötvös Loránd University and the Hungarian Natural History Museum, describe a new species of Bush Cricket from the ancient Caliman Caldera of the Eastern Carpathian Mountains in northern Romania.

The location of the Caliman Caldera. Google Maps.

The interior of the Caliman Caldera at (left) 1400 m and (right) 1600 m. Szövényi et al. (2012).

The new species is placed in the previously described genus Isophya, and given the specific name nagyi, in honour of Barnabás Nagy of the Plant Protection Institute of Hungarian Academy of Sciences, a leading expert on the Orthoptera (Crickets and Grasshoppers etc.) in Hungary.

The species is essentially similar to other species in the genera, a green Bush Cricket averaging 24 mm in length, and was identified on the basis of the male song, which is distinctive and indicates reproductive isolation. This is not simply a cultural difference, as in the songs of Whales or Primates, the song of a male Bush Cricket is preset by the physical structure of its stridulatory file.

Two colour variations of Isophya nagyi. Szövényi et al. (2012).

The stridulatory files of (A) Isophya nagyi, (B) Isophya camptoxypha, (C) Isophya ciucasi, (D) Isophya posthumoidalis, (E) Isophya sicula. (H) detail of the center part of the stridulatory file of Isophya nagyiSzövényi et al. (2012).

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Magnitude 7.7 Earthquake hits coast of British Columbia; tsunami threatens Hawaii.

On Saturady 27 October, slightly before 8.05 pm, local time (slightly before 3.05 am on Sunday 28 October, GMT), The Uniteed States Geological Survey recorded a Magnitude 7.7 Earthquke at a depth of 17.5 km on Queen Charlotte Island, off the coast of British Columbia. This is a very large  quake with the potential to cause considerable damage, though the area is sparsely populated which helps to mitigate this; the USGS estimates there is a 32% chance of a quake this size in this area causing at least one fatality, though no damage or casualties have been reported at the time of writing, 4½ hours after the quake.

The location of the 27 October Earthquake, and the areas that recieved the worst shaking. Damage to buildings is likely within the green circle, and more likely within the yellow circles. USGS.

The quake has been followed by a number of aftershocks, including over 10 with magnitudes over 4.0 so far, adding to the danger of serious casualties. In addition the NOAA Pacific Tsunami Warning Center has issued a severe tsunami alert for Hawaii, where an evacuation of coastal areas is underway.

The Queen Charlotte Islands lie on the boundary between the Pacific and North American Plates. This is a subductive margin, with the Pacific Plate passing under the islands as it sinks into the Earth. This is not a smooth process, and the plates frequantly stick together, then break apart once the peressure has built up sufficiently, leading to Earthquakes.

Map showing the boundary between the Pacific and North American Plates alomg the coast of British Columbia. Irving et al. (2012).

Earthquakes along subductive margins are particularly prone to causing tsunamis, since these often occur when the overlying plate has stuck to the underlying plate, being pulled out of shape by its movement.. Eventually the pressure builds up tp far and the overlying plate snaps back., causing an Earthquake and a tsunami.

Simplified graphic showing tsunami generation along a convergent margin. NASA/JPL/CalTech.

A new species of Pufferfish form French Polynesia.

Pufferfish of the genus Canthigaster (Sharp Nosed Puffers or Tobies) are small, widely distributed, tropical fish capable of inflating themselves as a defense mechanism, which both makes them larger (harder to swallow, more imposing) and exposes hidden spines. If this is not sufficient deterrent to predators, the Fish are also extremely toxic, producing a powerful neurotoxin in their livers, and sometimes other organs.

In a paper published in the journal Zootaxa on 23 October 2012, Jeffrey Williams of the Division of Fishes at the Department of Vertebrate Zoology at the US National Museum of Natural History, and Erwan Delrieu-Trottin and Serge Planes of the Centre de Recherche Insulaire et Observatoire de l'Environnement at the Université de Perpignan, describe a new species of Pufferfish in the genus Canthigaster from off Kouaku Island in the Gambier Archipelago in French Polynesia.

Satellite image of Kouaku Island. Google Maps.

The new species is named Canthigaster criobe, from CRIOBE, the acronym for Centre de Recherche Insulaire et Observatoire de l'Environnement. The species is described from a single Fish, caught in a small surge channel in outer reef at a depth of 15-20 m. Despite having only a single specimen of the Fish, Williams et al. are confident in their diagnosis of it as being a distinct species, due to its distinctive stripy pattern, not seen in any other member of the genus. They suggest that it be given the common name 'Striped Toby'.

Canthigaster criobe. (Top) Photograph. (Bottom) X-ray radiograph. Williams et al. (2012).

Canthigaster criobe is a 38.7 mm Pufferfish with a distinct tan and orange striped body pattern. It has 17 spines on its pectoral fin, 9 rays on its dorsal fin, 9 rays on its anal fin and 9 branched rays on its caudal (tail) fin. It's spines are hidden in grooves and point to the real when relaxed, making it smooth to the tough when stroked from head to tail but prickly when stroked from tail to head.

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Saturday 27 October 2012

Tropical Storm Son-Tinh kills at least 24 in the Philippines.

Tropical Storm Son-Tinh hit the Philippines on Wednesday this week, 24 October 2012, causing widespread flooding in south and central parts of the country, and leaving at least 24 people dead, and another 15 000 displaced to emergency shelters. The storm left the country on Friday, crossing the South China Sea, and growing in strength to a Category 3 Typhoon. It is expected to hit northern Vietnam and southern China in the next two days (28-29 October).

Map showing the path and strength of Typhoon San-Tinh to date (27 October 2012), and the predicted future path of the storm. Tropical Storm Risk.

Tropical storms are caused by the warming effect of the Sun over tropical seas. As the air warms it expands, causing a drop in air pressure, and rises, causing air from outside the area to rush in to replace it. If this happens over a sufficiently wide area then the inrushing winds will be affected by centrifugal forces caused by the Earth's rotation (the Coriolis effect). This means that winds will be deflected clockwise in the northern hemisphere and anti-clockwise in the southern hemisphere, eventually creating a large, rotating Tropical Storm.

In the west Pacific these are traditionally referred to as typhoons, but modern meteorologists prefer to restrict this term to storms with sustained wind strengths of 119 km/h or greater. When Son-Tinh hit the Philippines it had a  sustained wind strength of about 100 km/h, making it a 'Tropical Storm' rather than a Typhoon, but having crossed the Philippines the storm gained strength over the South China Sea, and is now classed as a Category 3 Typhoon, with sustained wind speeds in excess of 178 km/h.

Despite the obvious danger of winds of this speed, which can physically blow people, and other large objects, away as well as damaging buildings and uprooting trees, the real danger from these storms comes from the flooding they bring. Each drop millibar drop in air-pressure leads to an approximate 1 cm rise in sea level, with big tropical storms capable of causing a storm serge of several meters. This is always accompanied by heavy rainfall, since warm air over the ocean leads to evaporation of sea water, which is then carried with the storm. These combined often lead to catastrophic flooding in areas hit by tropical storms, which is what has caused the problems in the Philippines.

Swollen river in Las Piñas, Luzon Island. Al Jazeera.

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Four new species of Leafhopper from Southern Africa.

Leafhoppers are small Insects belonging to the True Bug order, Hemiptera. They are mostly herbivorous, using needle-like mouthparts to drill into plants and drain their sap. Leafhoppers form large colonies on plants, containing adults of both sexes as well as nymphs, larvae that resemble small adults and which only undergo partial metamorphosis during growth. Some species of Leafhopper form symbiotic relationships with Ants, producing secretions consumed by the Ants in return for protection from predators.

In a paper published in the journal Zootaxa on 8 October 2012, Michael Stiller of the Biosystematics Division at the ARC-Plant Protection Research Institute in South Africa describes four new species of Leafhopper found growing on plants of the genus Xerophyta (drought tolerant Monocotyledonous shrubs) in southern Africa.

The first new species described is placed in the new genus Xerophytavorus (eater of Xerophyta) and given the specific name furcillatus (little fork, referring to the shape of the tip of the abdomen). These are small (adults slightly over 2 mm), dark coloured Insects with white markings, found living on the plant Xerophyta splendens on Mulanje Mountain in Malawi, where they were attended by Ants of the genus Crematogaster. Such Leafhopper-Ant associations are common on Dicotyledonous (broad leafed) plants, but rare on Monocotyledons. Ants of the genus Crematogaster have previously been found tending a variety of Hemipterans (True Bugs) on a variety of plants, and are known to offer good protection against parasitoid Wasps (Wasps that lay their eggs on the Bugs, and whose larvae will the proceed to consume the Bud from the inside). On this occasion the Ants were found to build encasements of chewed plant material around the Leafhoppers. The grasslands where Xerophyta splendens grows are noted for regular scrub-fires, which the plant is able to tolerate. Xerophytavorus furcillatus was only found living on taller plants, suggesting it survives such events by remaining out of reach of the flames.

Xerophytavorus furcillatus. (Top) Male. (Bottom) Female. Stiller (2012).

Map showing the location of the site where Xerophytavorus furcillatus was discovered. Google Maps.

Xerophyta splendensSenckenberg Institute.

The second new species described is also placed in the genus Xerophytavorus and is given the specific name rastrullus (small rake or comb, in reference to to the shape of the tip of the abdomen). It was found living on Xerophyta retinervis, the Black Stick Lilly, a widespread but never abundant, hardy shrub in Gauteng, KwaZulu-Natal and North-West Provinces. Xerophytavorus rastrullus was attended by the small Ant Lepisiota incisa at Faerie Glen in Pretoria. This Ant has become widespread in many South African cities in recent years, and is known to have invaded the Kruger National Park, but is not believed to be native to South Africa. Other species of Ant were found tending Xerophytavorus rastrullus at other locations.

Xerophytavorus rastrullus. (Top) Female from Faerie Glen, Pretoria. (Upper Middle) Female from Dome Kloof, Magaliesberg, North-West Province. (Lower Middle) Nymph from Koppie Alleen, North-West Province. (Bottom) Female Swawelpoort, Pretoria. Stiller (2012).

Myrmecological associations. (Top and Upper Middle) Lepisiota incisa tending leafhoppers, Faerie Glen. (Lower Middle) Myrmicaria natalensis tending Xerophytavorus rastrullus, Irene, Pretoria. (Bottom) Camponotus eugeniae tending Xerophytavorus rastrullus, Magaliesberg, North-West Province. Stiller (2012).

(Left) Xerophyta retinervis, the Black Stick Lilly. Food and Agriculture Organization. (Right) The environment at Faerie Glen. Stiller (2012).

The third new species of Leafhopper described is placed in the new genus Xerophytacolus, meaning dweller on Xerophyta, and given the specific name claviverpus, meaning spiny penis, due to a feature of the male anatomy. The species was found living on Xerophyta retinervis in Gauteng, Mpumalanga and Limpopo Provinces, South Africa.

Xerophytacolus claviverpus. (Top) Nymph. (Bottom). Male. Both from Orrie Baragwanath Pass in Limpopo Province. Stiller (2012).

The final new species described is also placed in the genus Xerophytacolus, and given the specific name tubuverpus,  meaning 'tubular penis', again due to the male anatomy. The two species in this genera are very similar, but have distinctive genitalia, suggesting reproductive isolation. This species was also found living on Xerophyta retinervis in Gauteng, Mpumalanga and Limpopo Provinces, South Africa.

Xerophytacolus tubuverpus. (Top) Male. (Middle) Female. (Bottom) Nymph. All from Faerie Glen, Pretoria. (Stiller 2012).

See also A new species of Leaf Bug from the Mangrove Forests of Singapore and ThailandTwo new species of True Bug from the Mesozoic of China and An Assassin Bug from the Palaeocene of Spitsbergen Island.

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Friday 26 October 2012

Magnitude 5.3 quake in southern Italy kills at least one person.

On Friday 26 October at 1.05 am local time (11. 05 pm on Thursday 25 October, GMT), the United States Geological Survey recorded a Magnitude 5.3 Earthquake at a depth of 3.8 km, roughly 5 km west of the small town of Morano Calabro, in the Calabria Region of southern Italy. This is a fairly large quake at a shallow depth, which leads to a high risk of damage and casualties, and this quake is known at the time of writing to have caused at least one death and damage to buildings over a fairly wide area.

The location of the 26 October Earthquake. Google Maps.

Italy is in an unusual tectonic setting, with the west of the country lying on the Eurasian Plate, but the east of the country lying on the Adriatic Plate, a microplate which broke away from North Africa some time in the past and which is now wedged into the southern margin of Europe, underlying eastern Italy, the Adriatic Sea and the west of the Balkan Peninsula. This, combined with the northward movement of the African Plate into Italy from the south, leads to uplift in the Apennine Mountains that run the length of the country, and makes Italy extremely prone to Earthquakes. 

Map showing the boundary between the Eurasian and Adriatic Plates in Italy. Columbia University.

Historically Italy has suffered a number of devastating Earthquakes that lead to large numbers of casualties, though in recent decades the country has made serious attempts to prevent this, with better warning systems and tighter building regulations, though the large number of historic buildings in Italy, which cannot easily be replaced (and any attempt to do so would be unlikely to succeed due to their high cultural value), meaning that the country is unlikely to be completely risk free any time soon.

This has been complicated by an ongoing series of corruption scandals in the Italian construction industry, and, alarmingly, the decision by a court earlier this week to gaol six leading Earth scientists for failure to predict a quake. It is unclear how this will affect Italy's future ability to deal with geohazards, as it is likely that scientists will refuse to participate in programs that might result in prosecutions. It is also rumored that a number of other scientists in related agencies have resigned their posts, either in protest or because they feel their positions have been to badly compromised by the implied loss of scientific freedom for them to continue.

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