Friday, 20 April 2018

Australopithecus africanus: Was 'Mrs Ples' a male?

The Sterkfontein Caves site, part of the wider ‘Cradle of Humankind’ complex in Gauteng State, South Africa, has yielded the largest known collection of specimens assigned to the Plio-Pleistocene Hominin species Australopithecus africanus. The site comprises a series of karstic caves (i.e. caves created by the action of water percolating through soft limestone) that would have been encountered by the Hominins both as cave openings at the surface that could provide potential shelter and as potholes into which they could fall. Australopithecus africanus specimen Sts 5 is the most complete cranium assigned to the species that has been found in South Africa. It dates from at least 2.1 million years ago, and is probably close to 2.5 million years old. The specimen was discovered in April 1947 by Robert Broom and John Robinson, and identified as a female by Broom, leading to the popular name for this specimen, 'Mrs Ples'. However, since this time a number of other palaeontologists have considered the specimen to be a male.

In a paper published in the South African Journal of Science on 30 January 2018, Gaokgatlhe Tawane of the Ditsong National Museum of Natural History, and Francis Thackeray of the Evolutionary Studies Institute at the University of the Witwatersrand, re-examine specimen Sts 5, with a view to conclusively determining its sex.

Specimen Sts 5 'Mrs Ples' from the collection of the Ditsong National Museum of Natural History. José Braga//Wilimedia Commons.

Australopithecus africanus is considered to have been much more sexually dimorphic than Modern Humans, with a marked difference in size between the larger males and the smaller females. Yet such differences are not in themselves reliable determinants of sex, as a small, or young, male can still potentially be smaller than a large female. 
Bloom originally considered Sts 5 to be a female based upon the small size of the canine tooth sockets. These today are 7.2 mm by 6.9 mm, which would be considered to be particularly small for a male, lending weight to the idea that the specimen was female. However, the specimen shows signs of acid damage, probably from having been treated with acetic acid at some point during preparation of the specimen. This could potentially eat away the tooth socket, which is essentially a cone shaped hole, so erosion around the outer part will reduce the width of the hole. Tawane and Thackeray consulted Bloom's original data on the skull, and found that he had recorded canine socket diameters of 9 mm and 7.6 mm, larger values which support the idea that the sockets have been shrunk by acid damage, and - importantly - are values that would be considered to be within the male size range today.

In 1999 palaeoanthropologist Charles Lockwood published a paper in which he examined the facial structures of a large number of Australopithecus africanus specimens, with a view to understanding sexual dimorphism in the species. He was unable to assign Sts 5 to a specific sex with any confidence, however he did feel that it was likely to be a male because of its prominent forehead and large eye sockets.

The sex of specimen Sts 5 has long been considered ambivalent due to its mixture of male and female features. Tawane and Thackeray believe that the 'female' features of the specimen can be attributed to poor preparation of the specimen, and therefore conclude that it should be regarded as a male.

See also...

http://sciencythoughts.blogspot.co.uk/2018/01/australopithecus-africanus-does.htmlhttp://sciencythoughts.blogspot.co.uk/2017/07/australopithecus-africanus-deciphering.html
http://sciencythoughts.blogspot.co.uk/2016/10/evidence-for-lichen-on-bones-of-homo.htmlhttp://sciencythoughts.blogspot.co.uk/2016/09/an-osteogenic-tumour-in-198-million.html
http://sciencythoughts.blogspot.co.uk/2016/09/evidence-of-lichen-growth-on-bones-of.htmlhttp://sciencythoughts.blogspot.co.uk/2016/08/malignant-osteosarcoma-in-17-million.html
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Thursday, 19 April 2018

Adelogorgia osculabunda, Adelogorgia hannibalis & Adelogorgia adusta: Three new species of Gorgonian from Costa Rica and Panama.

Octocorals are colonial Corals, Anthozoa, lacking the extensive mineralized skeletons of Stony Corals. Each polyp of the colony has only eight tentacles, giving the group its name, though these often have numerous side branches, giving them a feathery appearance. Gorgonians are a group of Octocaorals that tend to form fan shaped colonies in shallow environments with strong currents. The genus Adelogorgia currently contains two species, one from Baja California and one from the Galapagos Islands.

In a paper published in the journal Zootaxa on 5 January 2018, Odalisca Breedy of the Centro de Investigación en Estructuras Microscópicas at the Universidad de Costa Rica, and Hector Guzman of the Smithsonian Tropical Research Institute, describe three new species of Adelogorgia from the Pacific coasts of Costa Rica and Panama.

The first new species described is named Adelogorgia osculabunda, meaning 'the one that covers with kisses' in reference to the mouths of the polyps, which have distinctive red lips. This species forms fan shaped colonies reaching about 15 cm in height and about 15 cm in width, with two stems rising from a holdfast then dichotomously branching (branching by repeatedly splitting in two). These colonies are pink in colour, with prominent red polyp mounds. The species was found living at depths of between 40 and 60 m along the Pacific coast of Costa Rica, and at a depth of about 80 m in the Pearl Islands, off the Pacific coast of Panama.

Adelogorgia osculabunda, colony. Breedy & Guzman (2018).

The second species is named Adelogorgia hannibalis, meaning 'from Hannibal' in reference to Hannibal Bank, a coastal guyot-type seamount off the Pacific coast of Panama, within the Coiba National Park. This species also forms fan-shaped colonies, reaching about 18 cm in height and 16 cm in width, and orange in colour. This species is known only known from Hannibal Bank, where it was found growing at depths of between 180 and 200 m.

Adelogorgia hannibalis, colony. Breedy & Guzman (2018).

The third new species is named Adelogorgia adusta, meaning 'burnt', as it has a burnt or scorched appearance. This species forms bushy colonies up to 11 cm high and 13 cm across, red and orange in colour. This species was also found on Hannibal Bank, at depths of between 73 and 94 m.

Adelogorgia hannibalis, colony. Breedy & Guzman (2018).

See also...

http://sciencythoughts.blogspot.co.uk/2018/02/antipathozoanthus-obscurus.htmlhttp://sciencythoughts.blogspot.co.uk/2018/01/charting-long-term-coral-decline-in.html
http://sciencythoughts.blogspot.co.uk/2018/01/porites-australiensis-exceptionally.htmlhttp://sciencythoughts.blogspot.co.uk/2017/12/terpios-hoshinota-tracking-progress-of.html
http://sciencythoughts.blogspot.co.uk/2017/09/looking-for-animals-in-wengan-biota.htmlhttp://sciencythoughts.blogspot.co.uk/2017/04/flagelligorgia-gracilis-new-species-of.html
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Magnitude 4.7 Earthquake beneath western Antigua.

The United States Geological Survey recorded a Magnitude 4.7 Earthquake at a depth of 22.2 km roughly beneath western Antigua in the Lesser Antilles, slightly before 4.30 pm local time (slightly before 8.30 pm GMT) on Tuesday 17 April 2018. This was a moderate quake, and at some depth as well as some way offshore, and there are no reports of any casualties or serious damage, though the quake was felt on the islands of Antigua, Nevis, Saint Kitts, Montserat, and Guadeloupe.

The approximate location of the 9 February 2018 Lesser Antilles Earthquake. USGS.

The Lesser Antilles are located at the eastern fringe of the Caribbean Tectonic Plate. The Atlantic Plate (strictly speaking, an extension of the South American Plate which runs to the northeast of the Caribbean) is being subducted beneath this, and as it sinks into the Earth, is melted by the heat of the planets interior. Some of the melted material then rises up through the overlying Caribbean Plate as magma, fuelling the volcanoes of the Lesser Antilles Volcanic Arc. The subduction of the Atlantic Plate beneath the Caribbean Plate is not a smooth process, with the two plates constantly sticking together then breaking apart as the tectonic pressure builds up, causing Earthquakes in the process, though since the boundary between the two plates is some way to the east of the islands, Earthquakes in the Lesser Antilles tend to be both deep and offshore, which lessens their destructive potential.
 
 The subduction of the Atlantic Plate beneath the Caribbean Plate fuels the volcanoes of the Lesser Antilles Volcanic Arc. George Pararas-Carayannis.
 
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.
 
See also...
 
http://sciencythoughts.blogspot.co.uk/2018/03/warning-issued-to-shipping-after.htmlhttp://sciencythoughts.blogspot.co.uk/2018/02/magnitude-52-earthquake-to-north-of.html
http://sciencythoughts.blogspot.co.uk/2017/12/magnitude-52-earthquake-to-northeast-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/09/magnitude-46-earthquake-to-northeast-of.html
http://sciencythoughts.blogspot.co.uk/2017/05/shipping-warning-issued-after-eruption.htmlhttp://sciencythoughts.blogspot.co.uk/2017/03/magnitude-45-earthquake-to-north-of-st.html
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Massive Ghost Net seen with thousands of trapped Fish and Sharks in the Cayman Islands.

A massive Ghost Net (abandoned or lost fishing net) has been sighted this week in the Cayman Islands. Diver and fisherman Dominick Martin-Mayes and companion Pierre Lesieur reported seeing the floating net about 4 km to the north of Grand Cayman Island on Monday 16 April 2018. The net mass is estimated to be about 15 m in diameter and about 15 m deep, and contains thousands of trapped, and mostly dead, Fish and Sharks, suggesting that it has been in the water for a long time. The government of the Cayman Islands has issued a alert to shipping in the hope of relocating the net and tackling it.

Ghost Net sighted in the Cayman Islands this week with thousands of traped Fish and Sharks. Dominick Martin-Mayes and Pierre Lesieur.

Ghost Nets are considered to be a major threat to marine life, trapping thousands of Fish, Sharks, Crustaceans, Marine Mammals and Reptiles, Birds and other organisms every year. Nets are essentially designed to trap and kill Fish, and abandoned nets generally continue to do so very effectively, indeed they are often more dangerous than nets in use, as the abandoned net becomes filled with dead animals, the scent of which attracts more scavenging and predatory organisms, which then in turn become trapped.

See also...

http://sciencythoughts.blogspot.co.uk/2018/04/pipeline-rupture-leads-to-massive-oil.htmlhttp://sciencythoughts.blogspot.co.uk/2018/01/iranian-tanker-burning-off-coast-of.html
http://sciencythoughts.blogspot.co.uk/2017/09/cleanup-operation-underway-after-oil.htmlhttp://sciencythoughts.blogspot.co.uk/2017/02/persistent-organic-pollutants-in.html
http://sciencythoughts.blogspot.co.uk/2017/02/reducing-levels-of-pathogenic-bacteria.htmlhttp://sciencythoughts.blogspot.co.uk/2016/08/grounded-oil-rig-loses-around-56-000.html
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Asteroid 2018 GE3 passes the Earth.

Asteroid 2018 GE3 passed by the Earth at a distance of about 193 000 km (0.50 times the average distance between the Earth and the Moon, or 0.13% of the distance between the Earth and the Sun), slightly after 6.40 am GMT on Sunday 15 April 2018. There was no danger of the asteroid hitting us, though were it to do so it would have presented a significant threat. 2018 GE3 has an estimated equivalent diameter of 33-100 m (i.e. it is estimated that a spherical object with the same volume would be 33-100 m in diameter), and an object at the upper end of this range 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 about 225 times as powerful as the Hiroshima bomb. Such an impact would result in an impact crater over a kilometre in diameter and devastation on a global scale, as well as climatic effects that would last years or even decades.

Asteroid 2018 GE3 passing in front of the constellation of Serpens on 14 April 2018, as seen from Weißenkirchen in Austria. Michael Jäger/Space.

2018 GE3 was discovered on 14 April 2018 (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 2018 GE3 implies that it was the 80th asteroid (asteroid E3) discovered in the first half of April 2018 (period 2018 G).
 
The calculated orbit of 2018 GE3. Minor Planet Center.
 
2018 GE3 has a 918 day orbital period and an eccentric orbit tilted at an angle of 8.74° to the plane of the Solar System, which takes it from 0.32 AU from the Sun (i.e. 32% of he average distance at which the Earth orbits the Sun, inside the orbit of the planet Mercury) to 3.38 AU from the Sun (i.e. 338% of the average distance at which the Earth orbits the Sun, and more than twice as distant 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 December 2015 and the next predicted in December 2020.
 
See also...
 
http://sciencythoughts.blogspot.co.uk/2018/04/the-lyrid-meteor-shower.htmlhttp://sciencythoughts.blogspot.co.uk/2018/04/asteroid-2018-gn-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2018/04/asteroid-2018-gu1-passes-earth.htmlhttp://sciencythoughts.blogspot.co.uk/2018/04/asteroid-2018-eb-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2018/04/asteroid-2018-fk5-passes-earth.htmlhttp://sciencythoughts.blogspot.co.uk/2018/04/asteroid-2006-uf17-passes-earth.html
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Dendrobium naungmungense: A new species of epiphytic Orchid from Kachin State, Myanmar.

Myanmar is considered to be a hotspot for Orchid biodiversity, with a current estimate of around 800 species, which is probably somewhat lower than the actual figure. Despite this high level of diversity the Orchids of Myanmar have been little studied in recent decades, due to the country's political isolation and instability. The genus Dendrobium, is one of the largest Orchid general, with somewhere between 800 and 1500 species found across South, Southeast and East Asia, and Austrolasia as far as New Zealand. These are members of the Epidendroideae, the largest subfamily of Orchids, with over 15 000 described species, more than all other Orchid groups combined, and are usually tree-dwelling epiphytes (live on other plants, typically in the canopy of rainforest trees).

In a paper published in the journal PhytoKeys on 29 January 2018, Qiang Liu and Shi-Shun Zhou of the Southeast Asia Biodiversity Research Institute and Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Xiao-Hua Jin of the State Key Laboratory of Systematic and Evolutionary Botany at the Institute of Botany of the Chinese Academy of Sciences, Bo Pan, also of the Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, Kyaw Win Maung of the HponkanRazi Wildlife Sanctuary, Myint Zyaw of the Forest Research Institute of the Myanmar Forest Department Ministry of Environmental Conservation and Forestry, and Ren Li, Rui-Chang Quan, and Yun-Hong Tan, again of the Southeast Asia Biodiversity Research Institute and Xishuangbanna Tropical Botanical Garden of the Chinese Academy of Sciences, describe a new species of Dendrobium from Kachin State in northern Myanmar.

The new species is named Dendrobium naungmungense, meaning 'from Naungmung', in reference to the town of Naungmung, close to the site where the species was discovered. This is an epyphytic Orchid found growing on the trunks of trees on riverbanks in a tropical forest at an altitude of between 500 and 600 m above sealevel. The plants are pendant (i.e. hangs from the trunks of the trees rather than standing erect) and reaches 30-50 cm in length, with slender stems and narrow, lance-shaped leaves. Flowers are born on bracts, and are greenish yellow and scented.

Dendrobium naungmungense. (A) Habitat. (B) Plant. (C) Flower. (D) Lateral view of flower. Quiang Liu in Liu et al. (2018).

The species was only found at a single location, with a total of about 20 mature plants observed, despite three years of fieldwork having been carried out in the area. For this reason Liu et al. recommend that the species be treated as Critically Endangered under the terms of the International Union for the Conservation of Nature’s Red List of Threatened Species.

See also...

http://sciencythoughts.blogspot.co.uk/2018/04/govenia-polychroma-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/11/coelogyne-magnifica-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2017/08/coelogyne-putaoensis-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/01/habenaria-yookuaaensis-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2016/12/lecanorchis-tabugawaensis-new-species.htmlhttp://sciencythoughts.blogspot.co.uk/2016/04/epiphytic-orchids-from-lengguru-fold.html
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Colombian gold miners trapped by collapse at Marmato mine.

Sixteen gold miners were trapped by a roof collapse at the entrance to the San Pedro Mine in the 100 Peso Sector of Marmato in Caldas Department on Wednesday 18 April 2018. The miners were trapped between 15 and 20 m below the ground, but were not thought to have been in any immediate danger as ventilation to the mine was maintained (other the immediate danger of being crushed by falling rocks, the biggest risk to miners trapped in collapsed mines is running out of oxygen). Fourteen of the miners have now been released, with rescue teams in contact with the remaining two, who are said to be unhurt.

Rescued miners emerging from the San Pedro Mine in Marmato following the 18 April 2018 collapse. La Patria.

The town of Marmato has a long tradition of gold mining, and many small independently run gold mines, which have historically attracted miners from as far away as Cornwall in the UK. Since 2007 the town has been in dispute with the central government of Colombia, which has backed a plan to give the entire area to Gran Colombia Gold, which planned to strip mine the whole area, removing the town in the process. This plan was dropped in 2017, with Gran Colombia still retaining control of the area, but now planning to concentrate on deep-pit mining.

See also...

http://sciencythoughts.blogspot.co.uk/2018/01/thirteen-dead-after-landslide-pushes.htmlhttp://sciencythoughts.blogspot.co.uk/2018/01/magnitude-51-earthquake-in-santander.html
http://sciencythoughts.blogspot.co.uk/2017/11/landslide-kills-at-least-four-in-cauca.htmlhttp://sciencythoughts.blogspot.co.uk/2017/10/magnitude-51-earthquake-in-barinas.html
http://sciencythoughts.blogspot.co.uk/2018/01/magnitude-51-earthquake-in-santander.htmlhttp://sciencythoughts.blogspot.co.uk/2017/06/thirteen-dead-following-explosion-at.html
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