Saturday, 24 February 2018

Seneciobracon novalatus: A new species of Braconid Wasp from Cretaceous Burmese Amber.

Braconid Wasps are a hyper-diverse group of parasitoid Wasps (Wasps with larvae that live inside the body of another Arthropod, slowly consuming it as they grow), with over 21 000 described species alive today, and many more species being described all the time. The Braconids have an excellent fossil record during the Cainozoic, with many modern groups found early in this period, suggesting that they probably first appeared and diversified early in the Cretaceous. However, specimens from the Cretaceous are much rarer, making the early history of the group hard to understand.

Cretaceous ‘Burmese Amber’ has been extensively worked at several sites across northern Myanmar (though mostly in Kachin State) in the last 20 years. The amber is fairly clear, and often found in large chunks, providing an exceptional window into the Middle Cretaceous Insect fauna. This amber is thought to have started out as the resin of a Coniferous Tree, possibly a Cypress or an Araucaria, growing in a moist tropical forest. This amber has been dated to between 105 and 95 million years old, based upon pollen inclusions, and to about 98.8 million years by uranium/lead dating of ash inclusions in the amber. 

The new species is named Seneciobracon novalatus, where ‘Seneciobracon’ means ‘Old Man Braconid’ and ‘novalatus’ means ‘new wing’. The species is described from a single female specimen, 2 mm in length, from a piece of amber from the Hukawng Valley in Kachin State, northern Myanmar. This species is thought not to belong to any living Braconid group, but rather to a previously unknown, extinct lineage, and is therefore placed in its own separate subfamily, named the Seneciobraconinae.

Photographs of female of Seneciobracon novalatus, in mid-Cretaceous amber from northern Myanmar. (A) Specimen in right lateral view as preserved. (B) Inset detail of pterostigmal region of forewing, depicting small costal cell. Engel et al. (2018).

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Woman bitten by Shark in Botany Bay, New South Wales.

Several beaches in New South Wales, Australia, have been temporarily closed after a woman was bitten by a Shark while swimming off Little Congwong Beach in the Kamay Botany Bay National Park on Friday 23 February 2018. The unnamed 55-year-old woman was attacked around dusk by a Great White Shark, Carcharodon carcharias, 27.-3.2 m in length, which bit her once on the leg before retreating. She is being treated in St George Hospital in Sydney, but is not thought to have received any dangerous injuries.

Woman being rushed from Little Congwong Beach by paramedics after being bitten by a Shark on 23 February 2018. Channel 9.

Despite their fearsome reputation, attacks by Sharks are relatively rare, with no recorded events near Botany Bay in at least 25 years. Most attacks on Humans by Great White Sharks are thought to be mistakes. The species feeds principally on Marine Mammals, which we superficially resemble when we enter the water, gaining the majority of their nutrition from the thick adipose (fat) layers of these animals, which we lack. Due to this, when Great Whites do attack Humans these attacks are often broken off without the victim being consumed. Such attacks frequently result in severe injuries, but are seldom immediately fatal, with victims likely to survive if they receive immediate medical attention.

A Great White Shark striking at prey. Brandon Cole/NPL.

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Asteroid 2002 LX passes the Earth.

Asteroid 2002 LX passed by the Earth at a distance of about 18 000 000 km (46.7 times the average distance between the Earth and the Moon, or 12.0% of the distance between the Earth and the Sun), slightly before 3.55 pm GMT on Monday 19 February 2018. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2002 LX has an estimated equivalent diameter of 120-390 m (i.e. it is estimated that a spherical object with the same volume would be 120-390 m in diameter), and an object of this size would be predicted to be capable of passing through the Earth's atmosphere relatively intact, impacting the ground directly with an explosion that would be 3000 to 150 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater 1.5-6 km in diameter and devastation on a global scale, as well as climatic effects that would last years or even decades.

The calculated orbit of 2002 LX. Minor Planet Center.

2002 LX was discovered on 3 June 2002 by the Massachusetts Institute of Technology's Lincoln Near Earth Asteroid Research Laboratory in Socorro, New Mexico. The designation 2002 LX4 implies that it was the 23rd asteroid (asteroid X) discovered in the first half of June 2002 (period 2002 L).

2002 LX has a 1456 day orbital period and an eccentric orbit tilted at an angle of 3.24° to the plane of the Solar System, which takes it from 0.83 AU from the Sun (i.e. 83% of he average distance at which the Earth orbits the Sun) to 4.19 AU from the Sun (i.e. 419% of the average distance at which the Earth orbits the Sun, and more than twice as distant from the Sun than the planet Mars). It is therefore classed as an Apollo Group Asteroid (an asteroid that is on average further from the Sun than the Earth, but which does get closer). This means that the asteroid has occasional close encounters with the Earth, with the last having occurred in March 2014 and the next predicted in February 2022. As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2017 YH1 is also classified as a Potentially Hazardous Asteroid. 2002 LX also has occasional close encounters with the planet Venus, which it last passed in June 1996.

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Wakaleo schouteni: A new species of Marsupial Lion from the Oligo-Miocene Riversleigh World Heritage Area of Queensland, Australia.

Marsupial Lions, Thylacoleonidae, are an extinct group of carnivorous Mammals from the Cainozoic of Australia. Many of these animals were large in size and showed dentition associated with a hypercarnivorous diet (diet composed almost entirely of meat), and are assumed to have been the top predators in the ecosystems where they lived. Members of the genus Wakaleo are dog-sized animals known from the Oligocene and Miocene of South Australia, Northern Territory and Queensland.

In a paper published in the Journal of Systematic Biology on 6 December 2017, Anna Gillespie, Michael Archer and Suzanne Hand of the PANGEA Research Centre at the University of New South Wales, describe a new species of Wakaleo from the late Oligocene to early Miocene sediments of the Riversleigh World Heritage Area in Queensland, Australia. 

The new species is named Wakaleo schouteni, in honour of palaeoartist Peter Schouten, for his reconstructions of the Riversleigh fauna and other prehistoric Australian animals. It is described from an almost complete skull, preserved in two halves, with most molar teeth intact, plus several fragmentary jaw sections, and a left and right humerus (from separate locations).

Wakaleo schouteni; (A) left lateral view; (B) left lateral view with jugal removed (hatched area) and M4 included; (C), posterior view. Abbreviations: al, alisphenoid; C, canine; eam, external auditory meatus; fm, foramen magnum; for, foramen rotundum; fr, frontal; iof, infraorbital foramen; jg, jugal; lac, lacrimal; lacf, lacrimal foramen; M, molar; max, maxilla; mf, maxillary foramen; mp, mastoid process; ms, mastoid; nc, nuchal crest; ns, nasal; oc, occipital condyle; os, orbitosphenoid; P, premolar; pal, palatine; par, parietal; pgp, postglenoid process; pmx, premaxilla; pop, paroccipital process; pt, pterygoid; ptp, pterygoid process of the alisphenoid; sc, sagittal crest; so, supraoccipital; sof, sphenorbital fissure; sop, supraorbital process; spf, sphenopalatine foramen; sq,squamosal; ssf, subsquamosal fossa; tvc, transverse canal. Gillespie et al. (2017). 

Wakaleo schouteni is one of the smallest members of the genus, with a total skull length of 164 mm, and an estimated living mass of between 22.6 and 24.0 kg (comparable to a Dalmation or Collie Dog). It is also one pf the earliest known members of the group, and has somewhat generalised dentition, something generally associated with an omnivorous diet, rather than a carnivorous one. This suggests that the genus may have began as small omnivorous animals with only a low amount of meat in their diet, then grown larger over time as they became more-and-more specialised for carnivorey, a pattern known from a variety of other groups.

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Landslide kills at least seven in Central Java.

Seven people are known to have died and at least thirteen more are missing following a landslide that hit the village of Pasir Panjang in the Brebes District of Central Java, Indonesia, on Thursday 22 February 2018. Several more people needed hospital treatment after the event, which has displaced about 250 people from their homes. The incident is reported to have occurred when a soil slope above the village after about two weeks of heavy rain in the area. Landslides are a common problem after severe weather events, as excess pore water pressure can overcome cohesion in soil and sediments, allowing them to flow like liquids. Approximately 90% of all landslides are caused by heavy rainfall.

Damage to buildings in the village of Pasir Panjang in Central Java, following the 22 February 2018 landslip. Oky Lukmansyah/Antara Foto/Reuters.

Landslides are a common problem in Java, particularly during the Northeast Monsoon, which lasts from November to February, with peak rainfall in January and February, and can result in an annual rainfall of around of 4000 mm in parts of Central Java. This problem has been made worse as expanding populations has led to people farming higher on hillslopes, in an area where soils tend to be volcanic in action and poorly consolidated (i.e. lack much cohesion), making them more prone to landslides.

The approximate location of the 22 February 2018 Pasir Pajang landslide. Google Maps.

Monsoons are tropical sea breezes triggered by heating of the land during the warmer part of the year (summer). Both the land and sea are warmed by the Sun, but the land has a lower ability to absorb heat, radiating it back so that the air above landmasses becomes significantly warmer than that over the sea, causing the air above the land to rise and drawing in water from over the sea; since this has also been warmed it carries a high evaporated water content, and brings with it heavy rainfall. In the tropical dry season the situation is reversed, as the air over the land cools more rapidly with the seasons, leading to warmer air over the sea, and thus breezes moving from the shore to the sea (where air is rising more rapidly) and a drying of the climate.

 Diagrammatic representation of wind and rainfall patterns in a tropical monsoon climate. Geosciences/University of Arizona.

Java has two distinct Monsoon Seasons, with a Northeast Monsoon driven by winds from  the South China Sea that lasts from November to February and a Southwest Monsoon driven by winds from the southern Indian Ocean from March to October. Such a double Monsoon Season is common close to the equator, where the Sun is highest overhead around the equinoxes and lowest on the horizons around the solstices, making the solstices the coolest part of the year and the equinoxes the hottest. 

The winds that drive the Northeast and Southwest Monsoons in Southeast Asia. Mynewshub.

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Friday, 23 February 2018

Magnitude 5.0 Earthquake beneath the Ionian Sea.

The United States Geological Survey recorded a Magnitude 5.0 Earthquake at a depth of 16.7 km, in beneath the Ionian Sea to the west of the island of Zakinthos, slightly before 1.45 am local time on Thursday 22 February 2018 (slightly before 11.45 pm on Wednesday 21 February GMT) . No damage or injuries have been reported following this event, but people have reported feeling the event on the islands of Zakinths and Ionia Nisea.

The approximate location of the 22 February 2018 Ionian Sea Earthquake. USGS.

The Ionian Sea overlies the boundary between the Aegean Sea Plate, which underlies southern Greece, and the African Plate, which underlies most of the Mediterranean. The African Plate is moving northward relative to the Aegean Sea Plate, and is being subducted beneath it along the Hellenic Trench, which runs from the Ionian Sea to the south and west of the Peloponnese and then to the south of Crete. This is not a smooth process, as the plates frequently stick together then break apart once the pressure has built up sufficiently, leading to (fairly frequent) Earthquakes.
The extent of the Hellenic Trench. Istituto Nazionale di Geofisica eVulcanologia.
Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. The international non-profit organisation Earthquake Report is interested in hearing from people who may have felt this event; if you felt this quake then you can report it to Earthquake Report here.

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Wednesday, 21 February 2018

Saltwater Crocodile kills man in Philippines.

A man has died after being attacked by a Saltwater Crocodile, Crocodylus porosus. on Balabac Island in the Philippines on Monday 19 February 2018. The man, identified as Rebente Ladja, 37, was reported missing when he failed to return home after setting traps for Crabs in a Mangrove Forest near his home. A search party later found his remains close to a large Saltwater Crocodile, which is presumed to have killed and partially eaten him.

A Saltwater Crocodile, Crocodylus porosus. Molly Ebersold/Wikimedia Commons.

This is the latest in a string of Crocodile attacks in the region, with five recorded attacks on Balabac Island since 2012, including a 12-year-old niece of Mr Ladja who is presumed dead after being dragged into the water by a Crocodile last year and never recovered.

The approximate location of the 19 February 2018 Balabac Crocodile attack. Google Maps.

Crocodile attacks on Humans are relatively rare, but they are opportunistic ambush predators and will potentially attack anything going close to the water. Saltwater Crocodiles have a particularly poor reputation for such behaviour, being the largest species of Crocodile and notoriously aggressive. These Crocodiles are one of the few Crocodile species not considered vulnerable to extinction, being found from India to Australia  and inhabiting many areas that Humans shun, such as Mangrove forests and islands without fresh water.

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