Thursday, 13 July 2017

Magnitude 5.0 Earthquake to the northeast of West Nusa Tenggara, Indonesia.

The Badan Nasional Penangulanggan Bencana (Indonesia's Disaster Mitigation Agency), reported a Magnitude 5.0 Earthquake about 50 km to the northwest of the city of Bima, on West Nusa Tenggara island, at about 10.30 pm local time (about 2.30 pm GMT) on Thursday 13 July 2017. There are no reports of any damage or injuries associated with this event, though people have reported feeling it on East Nusa Tenggara Island.

The approximate location of the 13 July 2017 West Nusa Tenggara Earthquake. Google Maps.
West and East Nusa Tenggara form part of the Lesser Sunda Islands, which are located on the northern part of the Timor Microplate. This is trapped between the converging Eurasian and Australian Plates, both of which are being subducted beneath it. In the south the Australian Plate is passing under the island of Timor, with material from the subducted plate melted by the friction and the heat of the Earth's interior rising through the Timor Plate to feed the volcanoes of the island. In the north the Eurasian Plate is being subducted in the same way, feeding the volcanoes there.
The subduction zones beneath the Timor Microplate. Hamson (2004).

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, 12 July 2017

Aenigmatoconcha clivicola: A new species of Helicarionid Land Snail from northeastern Thailand.

Helicarionid Land Snails of the Subfamily Durgellinae are found on limestone hills across South China and Southeast Asia. There are currently two described genera in the group, with Sophina found in southern Myanmar and Chalepotaxis found across southern China and Taiwan. This disjunctive distribution would seem to imply the group has diverged through allopatric speciation (i.e. the different groups have become separated from one-another geographically, then become reproductively isolated through genetic drift), however it is equally likely to be due to poor sampling, which is to say the groups could quite possibly be present together across much of their range but not have been found to date.

In a paper published in the Raffles Bulletin of Zoology on 7 June 2017, Chanidaporn Tumpeesuwan, also of the Department of Biology at Mahasarakham University, and Sakboworn Tumpeesuwan, also of the Department of Biology and of the Palaeontological Research and Education Centre at Mahasarakham University describe a new species of Durgelline Snail from Loei Province in northeastern Thailand.

The new species is deemed sufficiently different from any previously described species to be given a new genus, Aenigmatoconcha, meaning ‘riddle-shell’, and given the specific name clivicola, meaning ‘dweller on the side of a hill’. The species has a flattened shell 7.69–9.89 mm in height and 15.40–18.62 mm in width, with 5¼–5½ whorls when fully grown and a large aperture. The shell is glassy and pale brown in colour, while the foot is darker brown. 

Aenigmatoconcha clivicola, in natural habitat. Kitti Tanmuangpak in Tumpeesuwan & Tumpeesuwan (2017).

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Fourteen feared dead after landslide in Arunachal Pradesh, India.

Fourteen people are feared to have died after a landslide hit a village in the Papum Pare District of Arunachal Pradesh State, India, on Tuesday 11 June 2017. The event occurred at about 3.30 pm local time, and burried a number of houses in the village of Latap. Fourteen people were found to be missing after the landslip, the bodies of five of whom have subsequently bee recovered. It is thought unlikely that any of the none remaining missing persons are still alive.

Rescue operations in the village of Latap in Arunachal Pradesh on Tuesday 11 July 2017. Press Trust of India.

The incident is reported to have happened after four days of continuous rain in the area, associated with the summer rainy season. Landslides are a common problem after severe weather, 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. Arunchal Pradesh has a rainy season that begins around the end of April or beginning of May and ends around September, bringing 2-4000 mm of rain to the region each year.

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Sunday, 9 July 2017

Neovenator salerii: The neuroanatomy of the rostrum of an Early Cretaceous Allosauroid Dinosaur.

Neovenator salerii is an Early Cretaceous Allosauroid Theropod Dinosaur, known from a single partial skeleton from the Wessex Formation of the Isle of Wight. The skull of this skeleton is exceptionally well preserved, being deep and laterally (sideways) flattened, with blade-like teeth. This has been interpreted as indicative of a terrestrial apex predator, with a hunting technique that is likely to have involved targeting soft tissues, then defleshing with the sharp teeth, but avoiding biting down on bone or other hard tissue, which would produce wear marks on the teeth that are not seen (this is seen in some modern predators, such as Cheetahs).

In a paper published in the journal Scientific Reports on 16 June 2017, Chris Tijani Barker and Darren Naish of the National Oceanography Centre at the University of Southampton, Elis Newham and Orestis Katsamenis of the Faculty of Engineering and the Environment, also at the University of Southampton, and Gareth Dyke of the Department of Evolutionary Zoology and Human Biology at the University of Debrecen, and the Center for Interdisciplinary Biosciences at Pavol Jozef Safarik University, describe the results of a study of the cranial morphology of Neovenator salerii using microfocus μCT to investigate the distribution of its rostral foramina (the openings of channels within the bones of the snout through which nerves and blood vessels pass)and any internal preservation.

Barker et al. found that Neovenator salerii has an extensive network of channels within its maxilla and premaxilla running laterally (to the outside of) the dental alveoli, and connected to opening on the outer side of the bone. This is interpreted as part of the neurovascular system, occupying at least 7.3% and 6.7% of the internal volume of the premaxilla and maxilla, respectively. 

Complex anastomosing neurovasculature surrounding infilled dental alveoli of the premaxilla of Neovenator. (A) Volume rendering of left premaxilla in lateral view with foramina highlighted (blue). (B) Volume rendering of infilled voids. Barker et al. (2017).

Similar structures have previously been found in Pliosaurids (Mesozoic Marine Reptiles) and the Spinosaurids Spinosaurus and Baryonyx (Theropod Dinosaurs interpreted as having been partially aquatic). For this reason, the structures have been interpreted as sensory in nature, used to detect potential prey moving in the water. However, Neovenator appears to have no adaptations to an aquatic lifestyle, suggesting that the channels must have a different purpose.

Similar channels are found in a number of living animals notably some species of Birds, particularly those that engage in probe feeding, such as Kiwis (Apterygidae), Waders (Scolopacidae), and Ibises (Threskiornithidae), as well as in Ducks and Geese (Anseriformes), which use their beaks in a variety of ways for the detection, recognition, and transport of food, and Parrots (Psittaciformes), which are capable of extremely fine manipulation of objects with their beaks, including tool use. Beaks are known in a range of non-Avian Dinosaurs, including many Ornithischians and some Theropod groups, such as Ornithomimosaurs, Therizinosaurs, Oviraptorosaurs and some Ceratosaurs, but there is no evidence of any such structure in any Allosauroid, and nothing known about the biology of Neovenator suggests that it might have had a beak. 

Complex anastomosing neurovasculature surrounding infilled dental alveoli of the maxilla of Neovenator. (A) Volume rendering of left maxilla in lateral view with foramina highlighted (blue). (B) Volume rendering of infilled voids. Abbrevations: aor: antorbital ridge; asr: ascending ramus; ifs: interfenestral strut; laof: lateral antorbital fossa; maf: maxillary alveolar foramina; mcf: maxillary circumfenestra foramina; mfe: maxillary fenestra; mmf: medial maxillary foramina; pab: preantorbital body; pne: pneumatic excavation. Barker et al. (2017).

Channels of this type are also known in modern animals which lack beaks, notably Crocodylians, where it is associated with the detection potential prey moving in the water (as has been speculated for Pliosaurids and Spinosaurids), as well as temperature regulation. The very narrow snout seen in Neovanator makes a role in temperature regulation unlikely, as the snout would have shed excess heat (the only real issue for an animal this size) very efficiently without it. This makes it likely that the channels seen in the maxillary bones of Spinosaurus did indeed carry nerves rather than blood vessels. Barker et al. therefore speculate that the species, and other large Theropods such as Tyranosaurids, was probably capable of highly controlled snout movements, both when subduing prey and manipulating food, and that this would have been useful to an animal which needed to avoid brining very sharp, but not particularly strong, teeth into contact with the bone or other hard tissues of its prey.

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Pseudogobiopsis lumbantobing: A new species of freshwater Gobiid Fish from Java and Sumatra.

The freshwater Gobiid Fish genus Pseudogobiopsis is found from Thailand southeast to Papua New Guinea, though it is best known from the European aquarium trade, with collectors frequently sending professional ichthyologists photographs of unidentified species for identification.

In a paper published in the Raffles Bulletin of Zoology on 1 June 2017, Helen Larson of the Museum and Art Gallery of the Northern Territory and the Museum of Tropical Queensland, Renny Hadiaty of the Museum Zoologicum Bogoriense of the Indonesian Institute of Sciences and Nicolas Hubert of the Institut de Recherche pour le Développement, describe a new species of Pseudogobiopsis from the freshwater drainages of western Sumatra and western Java.

The new species is named Pseudogobiopsis lumbantobing, in honour of Daniel Lumbantobing of Jakarta, who collected the first specimens from the wild that were directly brought to the attention of scientists (although a number of aquarists had previously sent Helen Larson photographs of similar Fish of unknown provenance). The species is described from eighteen specimens, ranging from 18 to 33.5 mm in length, pearly grey in colour, with a with a white belly and a scattering of small orange spots. 
 Captive specimen of Pseudogobiopsis lumbantobing, imported via Singapore. Emma Turner in Larson et al. (2017).

This also potentially solves the mystery of a painting by Kuhl and van Hasselt, made between 1820 and 1823, of an unknown Gobiid Fish from Java. Unfortunately the original of this painting is in the collection of the Naturalis Library, which is currently undergoing renovation, so that the picture was in storage and unavailable for inspection prior to publication of the paper.

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Saturday, 8 July 2017

Sinkhole swallows bus in Veracruz, Mexico.

A bus was swallowed by a giant sinkhole in the city of Veracruz, in the Mexican state of the same name, on Friday 7 July 2017.  Nobody was hurt during the incident, as the bus was parked when the sinkhole opened,  but due to its large size, and the fact that it appears to be growing, at least twenty four neighbouring houses have been evacuated. Tn properties in other parts of the city have also been evacuated due to concerns about further sinkholes opening up.

Bus trapped in a sinkhole in Veracruz, Mexico, on 7 July 2017. Mexico News Daily.

Sinkholes are generally caused by water eroding soft limestone or unconsolidated deposits from beneath, causing a hole that works its way upwards and eventually opening spectacularly at the surface. Where there are unconsolidated deposits at the surface they can infill from the sides, apparently swallowing objects at the surface, including people, without trace.

The city of Veracruz is prone to sinkholes as it is located on soft limestone which is easily eroded by water; this weeks sinkholes have appeared after heavy rainfall in the area, with 125 mm falling in five hours this morning. This situation is made worse by the high level of seismic activity in Mexico, with even small tremors capable of repositioning deposits so that previously unexposed limestone layers come into contact with flowing water. In March 2016 the River Atoyac, which flows near the city, disappeared temporarily after a large sinkhole opened in its riverbed, an incident which is thought to have been triggered by a small Earthquake.

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Asteroid 2017 MC1 passes the Earth.

Asteroid 2017 MC1 passed by the Earth at a distance of  967 600 km (2.52 times the average distance between the Earth and the Moon, or 0.65% of the average distance between the Earth and the Sun), at about 9.25 pm GMT on Friday 30 June 2017. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2017 MC1 has an estimated equivalent diameter of 25-78 m (i.e. it is estimated that a spherical object with the same volume would be 25-78 m in diameter), and an object towards the upper end of this range 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 about 2 km above the ground, with an explosive force about 1150 times as large as that of the Hiroshima bomb; not large enough to cause long-lasting global problems, but fairly devastating for anyone directly underneath.

The calculated orbit of 2017 MC1. Minor Planet Center.

2017 MC1 was discovered on 20 June 2017 (10 days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2017 MC1 implies that it was the 28th asteroid (asteroid C1) discovered in the second half of June 2017 (2017 M).

2017 MC1 has a 1656 day orbital period and an eccentric orbit tilted at an angle of 0.88° to the plane of the Solar System, which takes it from 0.95 AU from the Sun (i.e. 95% of he average distance at which the Earth orbits the Sun) to 4.53 AU from the Sun (i.e. 453% of the average distance at which the Earth orbits the Sun, and over three times the orbit of 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 2017 MC1 and the Earth are not particularly common, though the asteroid does occasionally pass close to Jupiter, with this last having happened in November 2014.

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