Friday, 29 July 2016

Psectrosciara fossilis: A Dung Midge in amber from Chiapas State, Mexico.

Dung Midges, Scatopsidae, are minute True Flies, Diptera with a global distribution. They are a smal group, with about 259 species divided into four subfamilies, which have a very poor fossil record, but which are thought to be very ancient for biogeographical reasons. The Subfamily Psectrosciarinae, for example, is thought to have originated at latest in the Early Jurassic, but to date has yielded not a single fossil anywhere in the world.

In a paper published in the journal Palaeontologica Electronica in July 2016, André Nel and David Coty of the Institut de Systématique,Évolution, Biodiversité at the Muséum national d’Histoirenaturelle describe a Psectrosciarine Dung Midge preserved in amber from the Salt River Mine locality in Chiappas State, Mexico.

The Salt River Mine locality is located on the banks of the Salt River about 70 km southeast of Tuxtla Gutierrez and 1 km north of Totolapa. Amber from this locality has not been accurately dated, but is thought to be between 25 and 15 million years old, making it Late Oligocene to Middle Miocene in age.

The Midge is described as new species, placed in the extant genus Psectrosciara and given the specific name fossilis, indicating that it is the first fossil species in the genus described. The specimen is male, 2.7 mm in length, dark in colour, has ten antennal segments and a wing legth of 1.44 mm.

Psectrosciara fossilisin lateral view. Scale bar is 0.5 mm. Nel & Coty (2016).

See also...

http://sciencythoughts.blogspot.co.uk/2015/11/fossil-bee-flies-from-dominican.htmlFossil Bee Flies from the Dominican Republic and North America.                                     Bee Flies, Bombyliidae, are True Flies, Diptera, specialized for feeding on pollen and nectar, many of which have evolved long proboscises for nectar feeding. Many adult Bee Flies resemble Bees in shape and...
http://sciencythoughts.blogspot.co.uk/2015/08/preservation-of-haemoglobin-derived.htmlPreservation of haemoglobin-derived chemicals in a fossil Mosquito from the Eocene of Montana.                                             The 1993 film Jurassic Park speculated that Dinosaur DNA might be extracted from blood preserved inside Mosquitoes, Culcidae, trapped in amber during...
http://sciencythoughts.blogspot.co.uk/2015/05/protoplecid-flies-from-middle-jurassic.htmlProtoplecid Flies from the Middle Jurassic Daohugou Biota of Inner Mongolia.       Protoplecid Flies are a group of True Flies, Diptera, known from Jurassic deposits across Eurasia. They are thought to be ancestral to the modern Bibionidae (March Flies and Love Bugs) and the group...
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Thursday, 28 July 2016

Photogrammetry as a tool in Morphometric Analysis.

Morphometric analysis is a tool used by palaeontologists, archaeologists, anthropologists and forensic pathologists to analyse and compare specimens. It relies on taking numerous measurements of an object such as a bone or shell, and comparing both these measurements and ratios between measurements to those obtained from other specimens in order to establish relationships between them. Traditionally these measurements have been obtained using tape measures and callipers, but modern scientists often use more sophisticated tools such as structured light scanners, which are capable of building highly detailed three dimensional models of specimens. Photogrammmetry has been used as a tool in landscape analysis since the mid nineteenth century. It relies on taking overlapping images of a landscape, from a number of different vantages, in order to help cartographers and geomorphologists build up a three dimensional model of the landscape. The advent of digital photography has led to a far wider use of photogrammetry in the archaeology and other fields in the past two decades, with it becoming regularly used to build models of archaeological sites or even individual buildings. Recently some scientists have begun using photogrammetry to build models of smaller items, including archaeological artefacts and Human remains.

In a paper published in the Journal of Archaeological Science: Reports on 18 July 2016 a team of scientists led by Allowen Evin of the Institutdes Sciences de l'Evolution at Université de Montpellier, the Department of Archaeology at the University of Aberdeen, and the Department of Archaeology, Classics and Egyptology at the Universityof Liverpool, describe a process by which three dimensional computer models were constructed using digital photographs, and the results compared to the results of a morphometric model made to by structured light analysis.

Evin et al. examined a series of five modern Wolf skulls from the collection of the Muséum Nationald'Histoire Naturelle in Paris, as part of a study into morphometric changes to the cranium during the domestication of Dogs. In order to do this they created two models, one using a Breuckmann StereoScan structured light scanner and the other a model constructed from a series of photographs taken with a an 8 mega-pixel digital single-lens reflex (DSLR) Canon EOS 30D camera, mounted with a CanonEF 24–105mmf/4 L IS USM lens.

In order to take the photographs the specimens were placed on a rigid cardboard sheet with a calibrated referential pattern, and photograped from three different elevations (approximately 0°, 15° and 40°) using a tripod mounted camera, which was moved around the specimen taking images at 10° intervals (i.e. 36 sets of three images in a circle). This was then repeated with the skull the other way up, to give a model of the complete specimen. These images were then turned into a three dimensional model using a VisualSFM software package.

(A) Schematic representation of the set-up and camera positions used for the acquisition of the photographs. (B) Fixed dimensions reference pattern used to scale the models and enhance the performance of key-points detection/matching and camera calibration algorithms. Evin et al. (2016).

The photogrammatic model was then compared to the model made using the Breuckmann StereoScan structured light scanner (which rotates the specimens on its own automated turntable, creating a model using its own Optocat software package) using a computed mesh-to-mesh deviation map to compare the topology of the two models. This found that the two models matched to an average of 0.088 mm, with the only significant differences occurring within the nasal cavity and occipital foramen, areas which are generally considered extremely difficult to measure accurately, and which are not usually included in morphometric analyses.

Models obtained with photogrammetry (top) and the Breuckmann structured light scanner (bottom) with the cloud-mesh distances visualisation (middle). Differences are expressed using the colour scale on the left. Evin et al. (2016).

Evin et al. note the total tine spent with each specimen while capturing the images used to create the photogrammetric model was about 15 minutes, while the Breuckmann scanner required about forty five minutes to scan each specimen, although having scanned the specimens the Breuckmann scanner was able to produce a model almost instantaneously, while the camera method required considerable further input from the users, so that the Breuckmann scanner method took less time overall.

However since the Breuckmann scanner is not portable and is reliant on specimens being brought to it, Evin et al. felt that on the whole the advantages of the camera outweighed those of the scanner, as it could potentially be used in situations where specimens could not be moved, was considerably cheaper and captured additional information about the colour and surface texture of the specimen that were not recovered with the scanner.


See also...

http://sciencythoughts.blogspot.co.uk/2014/11/x-ray-computed-tomography-studies-of.htmlX-ray Computed Tomography studies of two Woolly Mammoth calves from Russia.            The Woolly Mammoth, Mammuthus primigenius, is thought to have diverged from the earlier Steppe Mammoth Mammuthus trogontherii in northeast...
http://sciencythoughts.blogspot.co.uk/2014/11/using-morphometric-analysis-to.htmlUsing morphometric analysis to understand the nature of Canid remains from Plio-Pleistocene Hominid sites from East Africa.                                                                        Morphometric analysis is a method used...
http://sciencythoughts.blogspot.co.uk/2014/04/reconstructing-paluxy-river-dinosaur.htmlReconstructing the Paluxy River Dinosaur Chase Sequence.                                            In 1940 palaeontologist Roland Bird of the American Museum of Natural History in New York described and partially excavated a sequence of Dinosaur footprints along the Paluxy River at Glen Rose in...

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Sunday, 24 July 2016

Pristimantis prometeii: A new species of Rain Frog from the cloud forests of El Oro in southern Ecuador.

The tropical forests of Central and South America are home to almost half of the known species of Amphibians, and since about a quarter of these species have been described in the past decade, this is likely to be a severe under-estimation of the true diversity of Amphibians in these forests. The largest group of Amphibians in these American tropical forests is the Brachycephaloidea, a group of Frogs with an entirely terrestrial life-cycle, laying eggs in moist habitats, which develop directly into small Froglets and missing out on the Tadpole stage altogether. About half of the described Brachycephaloidians are included in the most specieous genus of terrestrial vertebrates known, Pristimantis, members of which are commonly known as Rain Frogs, which contains almost 500 species.

In a paper published in the journal ZooKeys on 21 July 2016, Paul Székely of the Faculty of Natural and Agricultural Sciences at Ovidius University Constanţa and the Departamento de Ciencias Naturales at the Universidad Técnica Particular de Loja, Dan Cogălniceanu, also of the Faculty of Natural and Agricultural Sciences at Ovidius University Constanţa and of the Universidad Nacional de Loja, Diana Székely, again of the Faculty of Natural and Agricultural Sciences at Ovidius University Constanţa and the Departamento de Ciencias Naturales at the Universidad Técnica Particular de Loja, and of the Laboratory of Fish and Amphibian Ethology at the University of Liège, abd Nadia Páez and Santiago Ron of the Museo de Zoología at the Pontificia Universidad Católica del Ecuador, describe a new species of Robber Frog from the cloud forests of El Oro in southern Ecuador.

The new species is named Pristimantis prometeii, which refers to the Prometeo program of Secretaría de Educación Superior, Ciencia, Tecnología e Innovación of the Republic of Ecuador, through which Dan Cogălniceanu and Paul Székely received funding for their research in southern Ecuador. The Frogs are brown or green in colour with variable blotchy markings. Adult females reach 29.9–37.6 mm in length, males 20.4–24.9 mm.

Pristimantis prometeii, female specimen. Székely et al. (2016).

The species was found at three locations in the Reserva Buenaventura, at altitudes of between 878 and 1082 m. The species was observed in September in 2014 and 2015, generally after rain at night, when they could be found on leaves close to the forest floor (10-100 cm above the ground).

See also...

http://sciencythoughts.blogspot.co.uk/2015/11/eleutherodactylus-beguei-new-species-of.htmlEleutherodactylus beguei: A new species of Grass Frog from Guantánamo Province in southeast Cuba.                                          Small Grass Frogs are found across Cuba. Until 2012 these were all placed within a single species, Eleutherodactylus varleyi, but it was...
http://sciencythoughts.blogspot.co.uk/2015/04/robber-frogs-from-mountains-of-western.htmlRobber Frogs from the mountains of western Mexico.                                                                         Robber Frogs of the genus Eleutherodactylus are found from Texas to Guatemala and Belize and across the islands of the Caribbean. The genus was formerly the most specious of any genus of Vertebrate Animals (i.e. it contained more species than any other...
http://sciencythoughts.blogspot.co.uk/2014/08/a-new-cryptic-species-of-microhylid.htmlA new cryptic species of Microhylid Frog from Espírito Santo State, Brazil.                      Cryptic species are species which resemble one-another physically, and which cannot generally be separated using traditional taxonomic methodology, but which are nevertheless genetically and reproductively isolated. Genetic studies of many groups...
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Using a hypothetical ninth planet to explain the obliquity of the Solar System.

The major planets of our Solar System (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune) all orbit within a single plain, sometimes called the Plain of the Solar System, with none of the planets varying from this by more than a degree. This is consistent with the theory that the Sun and Planets formed from an initial disk of swirling matter within a larger nebulae. However the Sun itself is angled to this plain, rotating on a plane of axis six degrees out from that of the Plane of the Solar System. This is insignificant compared to some of the highly tilted orbits seen in exoplanets, with some known planetary systems hosting planets with orbits that vary by tens of degrees, but does require an explanation if our model of how the Solar System (and other stellar systems) formed is correct.

Several theories have previously been proposed to explain this obliquity. The young Sun could have been tilted from the plane by the activity of the stellar magnetosphere and its interactions with the protoplanetary disk, or the Sun could have started out with an asymetric distribution of mass in its core, leading to it acquiring an axial tilt. Alternatively the disc could have been tilted by a close encounter with another star or even a dense molecular cloud early in its life, or the Sun could have started out with a companion star that has subsequently been lost. However while all of these theories work on paper, there is no real way of either proving or disproving any of them at this time, which leaves us no closer to finding a solution to the mystery.

On 20 January 2016 Division of Geological and Planetary Sciences at the California Institute of Technology published a paper in The Astronomical Journal which suggested the observed clustering of objects in the Kuiper Belt might be attributable to the shepherding actions of a previously unknown planet with a mass 5-20 times that of the Earth and a highly eccentric orbit with an average distance from the Sun of 250 AU (i.e. 250 times the average distance between the Earth and the Sun).

Top view of the Keplerian trajectories of all bodies with a > 250AU as well as dynamically stable objects with a > 150AU. The two thin purple orbits correspond to stable bodies within the 150 < a < 250AU range. For each object, the directions of the angular momentum and Runge-Lenz (eccentricity) vectors are additionally shown. Batygin & Brown (2016).

In a paper published on the online arXiv database at Cornell University Library on 14 July 2016, Elizabeth Bailey of the Division of Geological and Planetary Sciences at the California Institute of Technology, along with Konstantin Batygin and Michael Brown, discus the posibility that such a hypothetical planet, refered to as Planet Nine, might be responsible for the obliquity of the Solar System.

It theory a large enough body in the Kuiper belt could exert sufficiant gravitational pull on the planets to alter their orbits, yet the planets would remain in the same plane of orbit as they gravitational pull they exert upon oneanother is greater than that exerted upon them by Planet 9. Importantly, unlike the other theories currently available, the existance of Planet nine, plus its size and orbit are potentially testable (since if such a planet exists it must be possible to directly observe it, even if this is not possible with current technology).

To this end Bailey et al. constructed a model of the Solar System, imputting the known parameters of the discovered planets, and assuming that they started orbitting in the same plane as the Solar Equator, plus a variety of different Planet 9s, in different orbits and having masses equivalent to 10, 15 ans 20 times that of the Earth.

Parameters of Planet Nine required to excite a spin-orbit misalignment of i = 6 deg over the lifetime of the solar system, from an initially aligned state. Contours in a9-e9 space denote i9, required to match the present-day solar obliquity. Contour labels are quoted in degrees. The left, middle, and right panels correspond to m9 = 10; 15, and 20mEarth respectively. Due to independent constraints stemming from the dynamical state of the distant Kuiper belt, only orbits that fall in the 150 < q9 < 350AU range are considered. The portion of parameter space where a solar obliquity of i = 6 deg cannot be attained are obscured with a light-brown shade. Bailey et al. (2016).


Bailey et al. found that a planet of any of the sizes modelled could potentially have caused the current obliquity of the Solar System over the 4.5 billion years of its existance, but (importantly) in order to do this it would need to be in an orbit much closer to that of the Plane of the Solar System then is predicted for the current orbit of Planet 9, based upon its influence on bodies in the Kuiper Belt. However this does not preclude the possibility that such a planer could be responsible for the obliquity, as it's orbit would also be effected by the gravitational interplay with the other planets of the Solar System (which are expected to have a much greater mass), potentially pushing it into a new orbit.

See also...

http://sciencythoughts.blogspot.co.uk/2016/05/hubble-space-telescope-discovers-moon.htmlHubble Space Telescope discovers a moon orbiting the Dwarf Planet Makemake. Makemake is the largest known body in the Kuiper Belt and the second-brightest Trans-Neptunian Object (after Pluto). It has a very bright albedo (it reflects a lot of light), with a surface apparently covered by...
http://sciencythoughts.blogspot.co.uk/2016/03/seasonal-exospheres-detected-on-dione.htmlSeasonal exospheres detected on Dione and Rhea.                                                    Exospheres are gas envelopes around planets and moons too thin to be considered true atmospheres. Unlike atmospheres, the gasses in exospheres are not thought to interact with one another, rather individual molecules are thought to be lost from the body's surface, spend some time in the exosphere, then either be lost into space or resettle onto the surface...
http://sciencythoughts.blogspot.co.uk/2016/03/sputnik-planum-apparently-young-feature.htmlSputnik Planum: An apparently young feature on the surface of Pluto.                                 Pluto was the first known and is one of the largest bodies in the Kuiper Belt, a field of Dwarf Planets and smaller bodies beyond Neptune which are thought to have been beyond the zone of true-planet formation, and therefore to reflect the nature of the early Solar System. In July 2015 the New Horizons spacecraft flew past Pluto, making a detailed survey of the surface...
 
 
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Asteroid 2016 OA passes the Earth.

Asteroid 2016 OA passed by the Earth at a distance of 1 734 000 km (4.50 times the average distance between the Earth and the Moon, or 1.16% of the average distance between the Earth and the Sun), at about 8.15 am GMT on Monday 18 July 2016. There was no danger of the asteroid hitting us, though had it done so it would have presented no threat. 2016 OA has an estimated equivalent diameter of 16-49 m (i.e. it is estimated that a spherical object with the same volume would be 16-49 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 25 and 9 km above the ground, with only fragmentary material reaching the Earth's surface.
 
 The calculated orbit of 2016 OAJPL Small Body Database.

2016 OA was discovered on 16 July 2016 (two days before its closest approach to the Earth) by the University of Arizona's Mt. Lemmon Survey at the Steward Observatory on Mount Lemmon in the Catalina Mountains north of Tucson. The designation 2016 OA implies that the asteroid was the first object (object A) discovered in the second half of July 2016 (period 2016 O).
 
2016 OA has a 1401 day orbital period and an eccentric orbit tilted at an angle of 1.09° to the plane of the Solar System that takes it from 0.75 AU from the Sun (i.e. 75% of the average distance at which the Earth orbits the Sun and slightly outside the orbit of Venus) to 4.15 AU from the Sun (i.e. 4.15% of the average distance at which the Earth orbits the Sun, considerably outside 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).
 
See also...
 
http://sciencythoughts.blogspot.co.uk/2016/07/asteroid-2016-nk22-passes-earth.htmlAsteroid 2016 NK22 passes the Earth.   Asteroid 2016 NK22 passed by the Earth at a distance of 264 500 km (0.69 times the average distance between the Earth and the Moon, or 0.18% of the average distance between the Earth and the Sun), at about 1.15 pm GMT on Monday 11 July 2016. There...
http://sciencythoughts.blogspot.co.uk/2016/07/asteroid-2016-na-passes-earth.htmlAsteroid 2016 NA passes the Earth.      Asteroid 2016 NA passed by the Earth at a distance of 483 100 km (1.26 times the average distance between the Earth and the Moon, or 0.32% of the average distance between the Earth and the Sun), slightly before 5.00 pm GMT on Friday 1 July 2016...
http://sciencythoughts.blogspot.co.uk/2016/06/asteroid-2004-kh17-passes-earth.htmlAsteroid 2004 KH17 passes the Earth.   Asteroid 2004 KH17 passed by the Earth at a distance of 16 990 000 km (30.2 times the average distance between the Earth and the Moon, or 11.4% of the average distance between the Earth and the Sun), slightly before 0.20 am GMT on Thursday 2 June...
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Jellyfish damage to farmed Salmon on the West Coast of Ireland.

Farmed Salmon are raised within caged enclosures in marine embayments, spending their entire lives within a limited area, unlike wild Salmon which roam over vast areas during their life-cycles, spending parts of their lives in marine environments and parts in freshwater. This makes farmed Salmon vulnerable to a variety of environmental threats that wild Salmon are able to avoid. One such threat is damage by Jellyfish swarms, which drift in vast numbers on the ocean currents, and which can cause significant damage when they encounter farmed Salmon, with smaller Jellyfish able to pass through cage meshes directly and adult specimens being broken up by the meshes, killing the Jellyfish but creating body fragments with still active stinging cells which could enter the cages. In one notorious case in 2007 a swarn of Mauve Stinger Jellyfish, Pelagia noctiluca, wiped out the entire stock of a Salmon farm in Northern Ireland, about 250 000 Fish.

In a paper published in the Journal of Fish Disease in January 2016, Mar Marcos-L opez, Susie Mitchell and Hamish Roger of Vet-Aqua International in Oranmore, County Galway, Ireland, descibe the results of a study of Jellyfish damage to farmed Salmon on the West Coast of Ireland in 2013.

The most abundant swarming Jellyfish seen on thw West Coast during the study peroid was the Mauve Stinger, however unidentified species of Phialella and Muggiaea were also recorded. Mauve Stingers are an entirely free-living species, unlike many Jellyfish which have a bottom-dwelling atteched polyp stage, enabling swarms drifting on ocean currents to continuously add to their own numbers (species with an attached polyp stage typically swarm for a season, then produce an overwintering polyp stage). They are found in vast numbers in all warm and temperate seas and oceans, though in seasonal climates they do die off in winter, so the biggest swarms are found in autumn and late summer, when seasonal storms often push them onto shores.

In 2013 Mauve Stingers swarms were reported at Salmon farms from August to November on the West Coast of both Northern Ireland and the Republic of Ireland, resulting in mortality rates among caged Salmon of up to 70%. Examination of both dead and live Salmon revealed numerous skin lessons, with Fish sufferning from respiratory distress (a syptom of Jellyfish venom), loss of apatite, apathy and increased jumping.

Numerous Pelagia noctiluca jellyfish inside marine Atlantic Salmon pen. Pete McDonagh in Marcos-L opez et al. (2016).

Many of the lessons caused by Jellyfish stings were found to be infected with a filamentous Bacterium, Tenacibaculum sp., which appeared to colonize necrotic Jellyfish filaments; these Bacteria are known to be carried by living Jellyfish, suggesting the infection was brought with the swarm, and was not just an opportunistic action by an organism living free in the water. The Salmon farmers responded to these infections by raising the levels of anti-biotics administered to the Fish.

See also...

http://sciencythoughts.blogspot.co.uk/2014/06/a-new-species-of-jellyfish-from-north.htmlA new species of Jellyfish from the North Adriatic Sea. While instantly familiar and biologically simple, Jellyfish (Scyphozoa) are still in many ways poorly understood, with frequently poorly understood life-cycles and population structures, leading to unexpected shifts in population and sudden blooms of large numbers of Jellyfish, which can impact on commercial...
http://sciencythoughts.blogspot.co.uk/2013/10/jellyfish-force-closure-of-swedish.htmlJellyfish force closure of Swedish nuclear power plant.                                   The Oskarshamn Nuclear Power Plant in Kalmar County on Sweden's southeast coast was forced to...
http://sciencythoughts.blogspot.co.uk/2013/06/the-mysterious-ebb-and-flow-of.htmlThe mysterious ebb and flow of Jellyfish populations.                                               Many scientists and conservationists are worried about the state of the world's oceans. Many important marine ecosystems are known to be under stress: once prolific fisheries have collapsed; dead


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