Friday 30 June 2017

Macrobiotus polypiformis: A new species of Tardigrade from the Ecuadorian Pacific coast.

Tardigrades, or Water Bears, are a distinctive group of small (usually less than 1 mm) invertebrates related to Arthropods, Nematodes and Velvet Worms. They have a simple segmented body with four pairs of limbs, and are remarkably resilient to environmental stress, being able to withstand extremely high and low temperatures, complete desiccation and even exposure to vacuum. To date about 1200 species of Tardigrade have been described, from marine, freshwater and terrestrial environments. Of these, only 227 have been described from South America, the majority of these from Chile, Argentina and Brazil. Ecuador is a large country in the northwest of South America, with a range of environments that can broadly be grouped into the western coastal lowlands, the central Andes Mountains, and the Amazon Basin in the east; yet to date only a single species of Tardigrade from Ecuador.

In a paper published in the European Journal of Taxonomy on 7 June 2017, Milena Roszkowska of the Department of Animal Taxonomy and Ecology at the Adam Mickiewicz University in Poznań, Marta Ostrowska of the Department of Avian Biology and Ecology, also at the Adam Mickiewicz University in Poznań, Daniel Stec of the Department of Entomology at Jagiellonian University, Karel Janko of the Laboratory of Fish Genetics at the Institute of Animal Physiology and Genetics of the Academy of Sciences of the Czech Republic, and Łukasz Kaczmarek, again of the Department of Animal Taxonomy and Ecology at the Adam Mickiewicz University in Poznań, describe a new species of Tardigrade from Manabí Province on the Ecuadorian Pacific coast.

The new species is named Macrobiotus polypiformis, in reference to processes found on the eggs of the species, which resemble the polyps of Cnidarians. The species is described from 96 specimens collected from a patch of Moss growing on a concrete wall, plus eggs and 36 second generation individuals obtained by culturing some of the original specimens in spring water. 

Macrobiotus polypiformis, dorso-ventral projection. (1) Taken using an Olympus BX41 phase contrast microscope. (2) Taken using an Olympus BX63 differential interference contrast microscope. Seen in DIC. Scale bars in μm. Rozkowska et al. (2017).

Adult individuals of the new species are 237–375 μm in length and white in colour, although they became transparent when fixed in Hoyer’s medium for viewing under a microscope. The mouth is surrounded by a ring of small pores, and has three rows of teeth, though only one of these could be seen under a light microscop.

Egg of Macrobiotus polypiformis. Rozkowska et al. (2017).  

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Monday 26 June 2017

Protesters invade North Mara Gold Mine in Tanzania.

About 500 protesters invaded the Acacia Mining operated North Mara Goldmine in the Tarime District of the Mara Region of Tanzania, last week, with 66 being arrested by police. Many of the protesters were armed with spears, machetes, and other traditional weapons, and a number of both police and protesters were injured in clashes at the site. The protesters were demanding compensation for the loss of artisanal mining rights, which were exercised at the site until it was acquired by Barrick Gold (now succeeded by Acacia Mines) in 2002, and to pollution from the site which has allegedly affected local farms.

Protesters at the North Mara Goldmine in Tanzania last week. Global Publishers.

The protests at the mine appear likely to be related to an ongoing dispute between Acacia Mining and the Government of Tanzania, which accuses the company of under-reporting profits and tax-evasion, and which has suspended exports of gold and copper from the country until such time as the dispute is settled. While the Tanzanian Government does not currently dispute the company's right to the site, or endorse the actions of the actions of the protesters, it is likely that the dispute with the government has encouraged the resumption of protests which have intermittently troubled the site.

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Asteroid 2017 MF passes the Earth.

Asteroid 2017 MF passed by the Earth at a distance of 391 500 km (1.01 times the average distance between the Earth and the Moon, 0.26% of the average distance between the Earth and the Sun), slightly before 10.30 pm GMT on Monday 19 June 2017. There was no danger of the asteroid hitting us, though had it done so it would have presented no threat. 2017 MF has an estimated equivalent diameter of 9-28 m (i.e. it is estimated that a spherical object with the same volume would be 9-28 m in diameter), and an object of this size would be expected to explode in an airburst (an explosion caused by superheating from friction with the Earth's atmosphere, which is greater than that caused by simply falling, due to the orbital momentum of the asteroid) in the atmosphere between 33 and 16 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2017 MF. Minor Planet Center.

2017 MF was discovered on 18 June 2017 (the day before its closest approach to the Earth) by the University of Arizona's Catalina Sky Survey, which is located in the Catalina Mountains north of Tucson. The designation 2017 MF implies that it was the sixth asteroid (asteroid F) discovered in the second half of June 2017 (period 2017 M).

2017 MF has a 721 day orbital period and an eccentric orbit tilted at an angle of 1.37° to the plane of the Solar System, which takes it from 0.99 AU from the Sun (i.e. 99% of he average distance at which the Earth orbits the Sun) to 2.15 AU from the Sun (i.e. 215% of the average distance at which the Earth orbits the Sun, considerably more than the distance at which the planet Mars orbits the Sun). 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 common, with the last having occurred in May 2013 and the next predicted for May 2019. 2017 MF also has occasional close encounters with the planet Mars, with the last calculated to have occurred in December 2000 and the next predicted for April 2074.  

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Thirteen dead following explosion at illegal coal mine in Colombia.

Thirteen mineworkers have been confirmed dead following an underground explosion at an illegal coal mine near the town of Cucunubá in Ubaté Province, Colombia, on Friday 23 June 2017. The bodies of eleven of the men were confirmed dead shortly after the explosion, with the remaining two, who it was initially hopes might have survived, being found the next day

Rescue operations at an illegal coal mine at Cucunubá, Colombia, destroyed by an explosion on 23 June 2017. Jaime Saldarriaga/Reuters.
The explosion is thought to have been caused by a build-up of methane gas at the mine, which like many similar unregulated mines lacked the ventilation equipment to remove excess gas. Coal is formed when buried organic material, principally wood, in heated and pressurised, forcing off hydrogen and oxygen (i.e. water) and leaving more-or-less pure carbon. Methane is formed by the decay of organic material within the coal. There is typically little pore-space within coal, but the methane can be trapped in a liquid form under pressure. Some countries have started to extract this gas as a fuel in its own right. When this pressure is released suddenly, as by mining activity, then the methane turns back to a gas, expanding rapidly causing, an explosion. This is a bit like the pressure being released on a carbonated drink; the term 'explosion' does not necessarily imply fire in this context, although as methane is flammable this is quite likely.

In addition, coal is comprised more or less of pure carbon, and therefore reacts freely with oxygen (particularly when in dust form), to create carbon dioxide and (more-deadly) carbon dioxide, while at the same time depleting the supply of oxygen. This means that subterranean coal mines need good ventilation systems, and that fatalities can occur if these break down.

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Sunday 25 June 2017

Brachylophus gau: A new species of South Pacific Iguana from Gau Island, Fiji.

Three living and one extinct species of South Pacific Iguana, Brachylophus spp., are known from the islands of Fiji, as well as a single species of a second genus Lapitiguana, a much larger, but also now extinct, Lizard. These Iguana’s are thought to have lived in isolation in the island group for around 40 million years, with their closest living relatives found in the deserts of the southwestern United States. Each species of South Pacific Iguana is recorded only from a single island, but several other islands of Fiji are known to host Iguanas, suggesting that either some of these species have greater ranges than has previously been recorded, or that there are undiscovered species of Iguana in the islands.

In a paper published in the journal Zootaxa on 6 June 2017, Robert Fisher of the San Diego Field Station of the U.S. Geological Survey’s Western Ecological Research Center, Jone Niukula of The National Trust of Fiji, Dick Watling of NatureFiji-MareqetiViti, and Peter Harlow of the Taronga Conservation Society, describe a new species of South Pacific Iguana from Gau Island, Fiji.

The new species is named Brachylophus gau, the Gau Iguana, and is distinguishable from all other members of the genus by the colouration of the throat, which is a plain green in both sexes. The species has a mean snout-vent length (length excluding the tail of 149.2 mm, and a maximum of 153 mm (the total length, including the tail, was not used as several specimens showed signs of having lost and regrown their tails, which will reduce this). These Iguanas are bright green in colour, shading from avocado green on their backs to sulphur green on their bellies, with a series of blue-grey bands on their body and tail. 

Illustration of the male, left, and female, right, of Brachylophus gau. The painting is from photographs of these specimens and others from life. Measurements to scale within illustration. The male is missing later 2/3 of tail, but tail drawn here based on photos from other males. Cindy Hitchcock in Fisher et al. (2017).

Although this species had not previously been recorded, examination of museum specimens found two additional examples of this Iguana in the collection of the Natural History Museum in London. These were donated by John MacGillivray of the H.M.S. Herald in 1855, with a recorded location only of ‘Fiji’. Examination of the MacGillivray’s private journal shows that the H.M.S. Herald did indeed visit Gau Island on 12 and 27 September 1854, where MacGillivray shot Green Iguanas hidden in the foliage of the Ivi (Tahitian Chestnut) Tree.

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Sichuan landslide feared to have killed over 100 people.

Over a hundred people are feared to have died following a landslide in a remote mountain village in Mao County in Sichuan Province, China, on Saturday 24 June 2017. The landslide struck the village of Xinmo at about 6.00 am local time, sweeping away all of the about forty homes in the village and damming a nearby river. So far only three survivors have been found, a couple and their two month old baby, all of whom are being treated in a nearby hospital, while 25 bodies have been recovered and 93 people are missing. A further 15 residents of the village have been confirmed safe as they were staying outside the community when the landslip occurred. Over three thousand rescue workers, assisted by specially trained dogs, are involved in the ongoing search, though there is thought to be little hope of finding any more survivors.

Rescue workers at the scene of the 24 June 2017 Sichuan landslide. Reuters.

The incident is reported to have been triggered by heavy rainfall 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. The climate of Sichuan Province is heavily influenced by the Asian Summer Monsoon, with heavy rainfall common in the summer. Xinmo is located on the province's Northern Plateau, where landslides are a common problem due to a mountainous terrain and limited vegetation cover.

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Friday 23 June 2017

Sedum danjoense: A new species of Succulent Plant from the Danjo Islands, Japan.

The Danjo Islands are a small group of uninhabited islands located about 170 km to the west of Kyushu in the South China Sea. The uninhabited islands have a total surface area of only 4.38 km², but are home to a range of organisms found nowhere else, including a subspecies of Snake, thirteen unique Land Snail species and a species of Orange Day Lily. The islands are designated as a national monument by Japan, and access to them is highly restricted.

In a paper published in the journal Phytotaxa on 9 June 2017, Takuro Ito of the United Graduate School of Agricultural Science at the Tokyo University of Agriculture and Technology, and the Department of Botany at the National Museum of Nature and Science, Hiroko Nakanishi of the Nagasaki Subtropical Botanical Institute, Yoshiro Chichibu and Kiyotaka Minoda of Nagasaki and Goro Kokubugata, also of the United Graduate School of Agricultural Science at the Tokyo University of Agriculture and Technology, and the Department of Botany at the National Museum of Nature and Science, describe a new species of Succulent Plant from the Danjo Islands.

The new species is described from a previously known population, which had been ascribed to the species Sedum formosanum, which is also known from Taiwan and the Philippines. However, the flowers are of Sedum formosanum elsewhere have five petals and ten stamens, while the Danjo Islands population have four petals and eight stamens. A study of the DNA of the Danjo population revealed them to be a distinct species, rather than just a local mutation, and this is species is described as Sedum danjoense, where ‘danjoense’ means ‘from Danjo’. 

Sedum danjoense. (A) Habitat and habit. (B) Inflorescence. (C) Adaxial surface. (D) Abaxial surface. (E) Flower. (F) Sepals. (G) Carpels. (H) Branching. Scale bars are 25 mm for (A), 5 mm for (B)–(H). Ito et al. (2017).

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Magnitude 6.8 Earthquake off the south coast of Guatemala.

The United States Geological Survey Recorded a Magnitude 6.8 Earthquake at a depth of 46.8 km about 23 km to the southwest of the city of Puerto San Jose on the Pacific Coast of  Guatemala, slightly after 6.30 am local time (slightly before 12.30 pm GMT) on Thursday 22 June 2017. This event was felt across much of central and southern Guatemala and El Salvador, as well as parts of neighbouring Mexico and Honduras, though there are no reports of any casualties or major damage, though minor damage to buildings has been recorded across a wide area, as well as several small landslides.

Damage to a building i Antigua, Guatemala,following an Earthquake on 22 June 2017. Luis Escheverria/Reuters.

Guatemala is located on the southern part of the Caribbean Plate, close to its boundary with the Cocos Plate, which underlies part of the east Pacific. The Cocos Plate is being pushed northwards by expansion of the crust along the East Pacific Rise, and is subducted beneath the Caribbean Plate along the Middle American Trench, which runs parallel to the south coast of Guatemala and neighbouring countries, passing under Central America as it sinks into the Earth's interior. This is not a smooth process, the plates tend to stick together, breaking apart again once the pressure from the northward movement of the Cocos Plate builds up to much, triggering Earthquakes.

The approximate location of the 22 June 2017 Guatemalan Earthquake. USGS.

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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