Monday 31 December 2018

Neolepas marisindica: A new species of Goose Barnacle from hydrothermal vents in the Indian Ocean.

Barnacles are Crustaceans, related to Shrimps, Crabs and Lobsters, but having a remarkably different lifestyle, with a free-swimming larval stage that then settles on rocks, or other substrates, and becomes an immobile filter-feeder, protected by a mineralised shell. Some species have become parasites on other Crustaceans, and have even more modified body-plans, growing through the host's tissues like a fungus. The genus Neolepas comprises Goose Barnacles (Barnacles with stalks) found around hydrothermal vents in the Pacific and Southern Oceans.

In the paper published in the journal Royal Society Open Science on 1 April 2018, Hiromi Watanabe of the Department of Marine Biodiversity Research at the Japan Agency for Marine-Earth Science and Technology, Chong Chen of the Department of Subsurface Geobiological Research also at the Japan Agency for Marine-Earth Science and Technology, Daniel Marie of the Mauritius Oceanography Institute, Ken Takai also of the Department of Subsurface Geobiological Research at the Japan Agency for Marine-Earth Science and Technology, Katsunori Fujikura, again of the Department of Marine Biodiversity Research at the Japan Agency for Marine-Earth Science and Technology, and Benny Chan of the Biodiversity Research Center at Academia Sinica, describe a new species of Neolepas from hydrothermal vents in the Indian Ocean.

The new species is named Neolepas marisindica, where 'marisindica' means 'Indian sea', in reference to the area where it was found. It has an outer shell composed of eight calcified plates, 26 scales per whirl on its stalk and a hatchet shaped mandible. The species appears to be widely distributed in the Indian Ocean, having been found in the Kairei and Solitaire vent fields on the Central Indian Ridge, the Longqi Hydrothermal Field on the South West Indian Ridge, and an unnamed site on the South East Indian Ridge.

Two specimens of Neolepas marisindica from the Kairei Vent Field on the Central Indian Ridge. Watanabe et al. (2018).

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Magnitude 1.6 Earthquake in Sunderland, northeast England.

The British Geological Survey recorded a Magnitude 1.6 Earthquake at a depth of 1 km about 2 km to beneath Sunderland in Tyne and Wear, northeast England, slightly after 1.05 pm GMT on Wednesday 26 December 2018. There are no reports of any damage or injuries associated with this event, and nor would they be expected from such a small event, though it is possible it was felt locally.
The approximate location of the 26 December 2018 Sunderland Earthquake. Google Maps.
Earthquakes become more common as you travel north and west in Great Britain, with the west coast of Scotland being the most quake-prone part of the island and the northwest of Wales being more prone  to quakes than the rest of Wales or most of England. However, while quakes in southern England are less frequent, they are often larger than events in the north, as tectonic pressures tend to build up for longer periods of time between events, so that when they occur more pressure is released.
The precise cause of Earthquakes in the UK can be hard to determine; the country is not close to any obvious single cause of such activity such as a plate margin, but is subject to tectonic pressures from several different sources, with most quakes probably being the result of the interplay between these forces.
Britain 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. It is also affected by lesser areas of tectonic spreading beneath the North Sea, Rhine Valley and Bay of Biscay. Finally the country is subject to glacial rebound; until about 10 000 years ago much of the north of the country was covered by a thick layer of glacial ice (this is believed to have been thickest on the west coast of Scotland), pushing the rocks of the British lithosphere down into the underlying mantle. This ice is now gone, and the rocks are springing (slowly) back into their original position, causing the occasional Earthquake in the process.
  (Top) Simplified diagram showing principle of glacial rebound. Wikipedia. (Bottom) Map showing the rate of glacial rebound in various parts of the UK. Note that some parts of England and Wales show negative values, these areas are being pushed down slightly by uplift in Scotland, as the entire landmass is quite rigid and acts a bit like a see-saw. Climate North East.
Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. If you felt this quake, or were in the area but did not (which is also useful information) then you can report it to the British Geological Survey here.   
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Sunday 30 December 2018

Lutjanus sebae & Pterois miles: An association between juvenile Emperor Red Snappers and Common Lionfish off the coast of Nosy Be Island, Madagascar.

Lionfish, Pterois spp., are large predatory Fish from the Indo-Pacific region that have become a serious invasive pest in several other parts of the world. They are willing to take a wide range of prey and have a novel hunting technique, hovering over the prey fish then, disorientating the prey by flaring their large pectoral fins and sometimes blowing jets of water at the prey prior to striking. Furthermore, Lionfish are venomous, producing a potent toxin on spines on their dorsal, anal and pectoral fins. These adaptations make them a formidable and dangerous part of any ecosystem where they are found, and most other Fish will avoid them wherever possible.

In a paper published in the journal Coral Reefs on 31 October 2018, Davide Seveso, Simone Montano and Davide Maggioni of the Marine Research and High Education Centre on Magoodhoo Island in the Maldives, publish an account of an observed association between juvenile Emperor Red Snappers, Lutjanus sebae, and the Common Lionfish, Pterois miles, off the coast of Nosy Be Island, Madagascar.

The association was observed during a dive off Nosy Be in August 2018, during which a number of juvenile Emperor Red Snappers were seen in close association with Common Lionfish, swimming close to them, and often within their fins. Juveniles of this species often form close associations with Sea Urchins, remaining within the spines of the Echinoderms until they grow to large, and thereby gaining the benefit of the Sea Urchin's spines as a defence. In this case the Snapers appeared to be using the Lionfish in a similar way, in an environment with a sandy bottom and no Sea Urchins. 

Juvenile Emperor Red Snapper next to a Common Lionfish. Seveso et al. (2018).

The benefits of this relationship to the juvenile Snappers seem fairly clear; they gain benefit from the Loinfish's defensive spines, and are in addition well camouflaged against the Lionfish, with both species having similar barred light–dark colour patterns, and may even be able to scavenge some of the Lionfish's food (both species are carnivores). However it is unclear what gain the Lionfish gets from this relationship, or if there is none why they endure the presence of the Snappers.

Juvenile Emperor Red Snapper hidden between the fins of a Common Lionfish. Seveso et al. (2018).

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Archetingis ladinica: A Lace Bug from the Middle Triassic of the Swiss side of Monte San Giorgio.

Lace Bugs, Tingidae, are small (2-10 mm) members of the True Bug Order Hemiptera, which get their common name from the lacy pattern of the veins of their wings. They are plant parasites, with each species having a specific host, and many species are significant agricultural pests. The oldest known fossil Lace Bugs date back to the beginning of the Cretaceous, however the global distribution of the group, combined with the wides range of host plants, which includes Mosses, Conifers and Horsetails, suggests that the group was established long before the breakup of the supercontinent of Pangea in the Late Jurassic.

In a paper published in the journal Rivista Italiana di Paleontologia e Stratigrafia in March 2018, Matteo Montagna of the Dipartimento di Scienze Agrarie e Ambientali - Produzione, Territorio, Agroenergia at the Università degli Studi di Milano, Laura Strada of the Dipartimento di Scienze della Terra “Ardito Desio” at the Università degli Studi di Milano, Paride Dioli of the Museo Civico di Storia Naturale di Milano, and Andrea Tintori, also of the Dipartimento di Scienze della Terra “Ardito Desio” at the Università degli Studi di Milano, describe a new species of Lace Bug from the Swiss part of the Middle Triassic Monte San Giorgio Fossil-Lagerstätte.

The Middle Triassic Monte San Giorgio Fossil-Lagerstätte outcrops on the mountain of the same name, overlooking Lake Lugano on the Swiss-Italian Border. The site is noted for the production of Marine Vertebrates of Anisian (247-242 million years ago) to Ladinian (242-247) age, for which it has been made a UNESCO World Heritage List site. However, the site does not simply preserve marine faunas, but preserves a complex paleoenvironment with a shallow lagoon with a surrounding area that contains numerous small pools and streams, connected to a marine environment with a carbonate platform. The Lower Kalkschieferzone beds on the Swiss side of the mountain have been dated to 239.51 million years ago (Early Ladinian) and have produced several Insect fossils, including Mayflies, Beetles and Bristletails.

The new Lace Bug is named Archetingis ladinica, meaning 'Ancient Lace Bug from the Ladiaian'. It is described from a single specimen from the Lower Kalkschieferzone beds. This specimen is 11.8 mm in length, larger than any living species of Lace Bug, though many Insect groups produce fossils larger than anything still living, including Bristletails from the Kalkschieferzone.

(A) Archetingis ladinica obtained by merging slab and counterslab; (B) reconstruction of Archetingis ladinicafeatures not preserved in the fossil (i.e., antennae and eyes) in grey. The white scale bar corresponds to 1 mm. Drawing by Matteo Montagna. Montagna et al. (2018).

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Panorpa bashanicola: A new species of Scorpionfly from the Bashan Mountains in central China.

The Scorpionflies (Mecoptera) are a group of insects related to the True Flies. They get their name from the reproductive organs of the males of some species, which resemble the tails of Scorpions. Despite this fierce appearance most species are harmless herbivores, though it is thought that fleas are highly specialised members of the group, and the True Flies, Butterflies and Moths may have evolved from the group in the Mesozoic. The group has a fossil record dating back to the Permian, and it has been suggested that the Scorpionflies were the first Insects to pollinate plants, possibly pollinating gymnospermous plants in the Jurassic before the origin of true flowering plants.

In a paper published in the journal ZooKeys on 30 July 2018, Yuan Hua and Shi-Heng Tao of the College of Life Sciences at Northwest A&F University, and Bao-Zhen Hua of the Key Laboratory of
Plant Protection Resources and Pest Management, and Entomological Museum at Northwest A&F University, describe a new species of Scorpionfly from the Bashan Mountains in central China.

The new species is placed in the genus Panorpa, and given the specific name bashanicola, in reference to the area where it was found. The species has a distinctive wing patterning, with two pale longitudinal stripes and four pale rounded spots on its forewings, and a head and body is brown in colour, with grey eyes. The species was found in Shaanxi and Hubei provinces.

Panorpa bashanicola, male in dorsal view (top left), female in dorsal view (top right) and male abdomen in dorsal view (bottom).

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Saturday 29 December 2018

Asteroid 2010 GT7 passes the Earth.

Asteroid 2010 GT7 passed by the Earth at a distance of about 9 444 000 km (24.6 times the average distance between the Earth and the Moon, or 6.31% of the distance between the Earth and the Sun), slightly before 6.45 am GMT on Monday 24 December 2018. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2010 GT7 has an estimated equivalent diameter of 170-540 m (i.e. it is estimated that a spherical object with the same volume would be 170-540 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 between 6000 and 600 000 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater between 2.5 and 8 km in diameter and devastation on a global scale, as well as climatic effects that would last decades or even centuries.

 The calculated orbit of 2010 GT7 Minor Planet Center.

2010 GT7 was discovered on 7 April 20108 by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2010 GT7 implies that it was the 194th asteroid (asteroid T7) discovered in the first half of April 2010 (period 2010 G).

2010 GT7 has an 1636 day orbital period and an eccentric orbit tilted at an angle of 9.26° to the plane of the Solar System, which takes it from 0.86 AU from the Sun (i.e. 86% of he average distance at which the Earth orbits the Sun) to 4.57 AU from the Sun (i.e. 457% of the average distance at which the Earth orbits the Sun, and slightly more than three times as far from the Sun as 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 close encounters between the asteroid and Earth are extremely common, with the last having occurred in March 2010 and the next predicted in March 2028. As an asteroid probably larger than 150 m in diameter that occasionally comes within 0.05 AU of the Earth, 2010 GT7 is also classified as a Potentially Hazardous Asteroid.

2010 GT7 also has frequent close encounters with the planets Mars, which it is  next predicted to pass in February 2114, and Jupiter, which it last came close to in September 1985 and is next predicted to pass in February 2025. Asteroids which make close passes to multiple planets are considered to be in unstable orbits, and are often eventually knocked out of these orbits by these encounters, either being knocked onto a new, more stable orbit, dropped into the Sun, knocked out of the Solar System or occasionally colliding with a planet.
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