Sunday, 21 January 2018

Cretalamna bryanti: A new species of Mackeral Shark from the Late Cretaceous of Alabama.

Mackerel Sharks of the genus Cretalamna are known from Early Cretaceous to Early Eocene deposits around the world, and are thought to have been ancestral to modern species such as the Great White and Mako, as well as distinctive prehistoric species such as the giant Carcharocles megalodon. Like other fossil Sharks these species are usually only represented by their teeth, which are mineralised and grown and shed throughout their lives, rather than their skeletons, which are made of soft cartilage. Consequently differentiating these Sharks to species level is difficult, and many Late Cretaceous specimens have been assigned to a catch all species, Cretalamna appendiculata.

In a paper published in the journal PeerJ on 8 January 2018, Jun Ebersole of the McWane Science Center and Dana Ehret of the Alabama Museum of Natural History at the University of Alabama and the New Jersey State Museum, describe a new species of Cretalamna from the Late Cretaceous Tombigbee Sand of Alabama.

The new species is named Cretalamna bryanti, in honour of the Bryant family for their support of the University of Alabama, the Alabama Museum of Natural History, and the McWane Science Center. Teeth assigned to Cretalamna have been collected from the Tombigbee Sand for many years, but assigned to Cretalamna appendiculata. Ebersole and Ehret carried out a morphometric analysis, a method that relies on comparing the ratios of different measurements to one-another rather than simply assigning the samples to groups based upon their obvious shape, in order to determine that these specimens did not belong to any previously described species.

Cretalamna bryanti, anterior teeth. (A)-( E) Upper right anterior tooth in (A) oral, (B) basal, (C) mesial, (D) lingual, and (E) labial views. (F)-( J) Upper right anterior tooth in (F) lingual, (G) labial, (H) mesial, (I) oral, and (J) basal views. (K )-(O) Upper left anterior tooth, large morphology, in (K) oral, (L) basal, (M) mesial, (N) lingual, and (O) labial views. (P)-( T) Lower right anterior tooth in (P) lingual, (Q) labial, (R) mesial, (S) oral, and (T) basal views. Scale bars equal 1.0 cm. Ebersol & Ehret (2018).

See also...

http://sciencythoughts.blogspot.co.uk/2017/12/shark-remains-from-early-cretaceous-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/12/american-tourist-killed-by-shark-in.html
http://sciencythoughts.blogspot.co.uk/2017/12/californian-student-recovering-after.htmlhttp://sciencythoughts.blogspot.co.uk/2016/09/megachasma-alisonae-megamouth-shark.html
http://sciencythoughts.blogspot.co.uk/2016/01/mollisquama-sp-pocket-shark-from-gulf.htmlhttp://sciencythoughts.blogspot.co.uk/2015/11/evidence-of-shark-predation-on-whale.html
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Small eruptions on Mount Chaparrastique, El Salvador.

The Servicio Nacional de Estudios Territoriales has reported a pair of small eruptions on Mount Chaparrastique, or San Miguel, a 2130 m stratovolcano (cone shaped volcano made up of layers of ash and lava) in east-central El Salvador. The first event occurred slightly after 4.50 pm local time on Sunday 14 January 2018, the second a day later at about 4.15 pm local time on Monday 15 January. Both produced small plumes that rose less than 300 m above the summit of the volcano. 

The approximate location of Mount Chaparrastique. Google Maps.

El Salvador, and neighbouring Central American states, lies on the Caribbean Plate. To the south of Central America the Coccos Plate, which underlies an area of the east Pacific, is being subducted beneath the Caribbean Plate along the Middle American Trench. As the plate is subducted it is partially melted by the friction and the heat of the planet's interior, giving rise to liquid magma which rises through the Caribbean Plate to fuel the volcanoes of Central America.

See also...

http://sciencythoughts.blogspot.co.uk/2017/11/hundreds-of-green-sea-turtles-found.htmlhttp://sciencythoughts.blogspot.co.uk/2016/11/magnitude-70-earthquake-off-coast-of-el.html
http://sciencythoughts.blogspot.co.uk/2016/01/activity-on-mount-chaparrastique-el.htmlhttp://sciencythoughts.blogspot.co.uk/2015/10/hurricane-patricia-most-severe-storm.html
http://sciencythoughts.blogspot.co.uk/2014/10/one-dead-after-central-american.htmlhttp://sciencythoughts.blogspot.co.uk/2014/05/volcanic-activity-on-chaparrastique.html
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Magnitude 6.3 Earthquake beneath the southern Gulf of California.

The United States Geological Survey recorded a Magnitude 6.3 Earthquake at a depth of 10 km beneath the Gulf of California, roughly 77 km off the coast of Baja California Sur State, Mexico, slightly after 8.15 am local time (slightly after 4.15 pm GMT) on Friday 19 January 2018. Although this was a large, shallow quake, and therefore potentially dangerous, it occurred some distance offshore, and while there are reports of it being felt over a wide area of Baja California Sur and Sinaloa states, there are no reports of any damage or injuries arising from this event.

The approximate location of the 19 January 2018 Gulf of California Earthquake. USGS.

The boundary between the Pacific and North American Plates runs beneath the Gulf of California, with Beja California lying on the Pacific Plate and the Mexican mainland on the North American. The Pacific Plate is moving northwest with regard to the North American Plate, while the North American Plate is moving southeast relative to the Pacific Plate. This creates a transform plate margin along the centre of the Gulf of California, as the two plates slide past one-another, a margin that continues northward under California as the San Andreas Fault. The plates do not move past one-another smoothly, but continuously stick together then break apart as the pressure builds up, leading to regular Earthquakes beneath the Gulf of California and in the surrounding area.

 Map showing the relative movement of the Pacific and North American Plates, and the fault system beneath the Gulf of California. Monterey Bay Aquarium.

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/2017/03/magnitude-57-earthquake-beneath-gulf-of.htmlhttp://sciencythoughts.blogspot.co.uk/2013/12/magnitude-42-earthquake-in-northern.html
http://sciencythoughts.blogspot.co.uk/2013/12/magnitude-46-earthquake-in-baja.htmlhttp://sciencythoughts.blogspot.co.uk/2013/10/magnitude-65-earthquake-beneath-gulf-of.html
http://sciencythoughts.blogspot.co.uk/2013/09/magnitude-28-earthquake-in-baja_30.htmlhttp://sciencythoughts.blogspot.co.uk/2013/09/magnitude-41-earthquake-in-northeast_16.html
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Saturday, 20 January 2018

Caihong juji: A new species of Paravian Dinosaur from the Middle-Late Jurassic Tiaojishan Formation of Hebei Province, China.

The Paravians are a group of Maniraptoran Theropod Dinosaurs which includes the Birds, plus their closest relatives the Dromaeosaurs, Troodontids, Anchionithids, and Scansorioptererygids. Most of species of these Dinosaurs are known from the Late Jurssic and Cretaceous (later in the case of Birds) and can be confidently assigned to one of the derived groups that make up the Paraves, however the Middle-Late Jurassic Tiaojishan Formation of Hebei Province in China has produced a number of early Paravian Dinosaurs that appear to date from around the time that these groups diverged and which cannot always be confidently assigned to one group, including some specimens which may be the earliest known Birds (the Tiaojishan Formation is thought to be slightly older than the Solnhofen Limestone which produced the generally accepted first known fossil Bird, Archaeopteryx lithographica.

In a paper published in the journal Nature Communications on 15 January 2017, Dongyu Hu of the Paleontological Museum of Liaoning and Key Laboratory for Evolution of Past Life in Northeast Asia at Shenyang Normal University, Julia Clarke of the Department of Geological Sciences and Integrated Bioscience at the University of Texas at Austin, Chad Eliason, also of the Department of Geological Sciences and Integrated Bioscience at the University of Texas at Austin, and of the Integrative Research Center at the Field Museum of Natural History, Rui Qiu, also of the Paleontological Museum of Liaoning and Key Laboratory for Evolution of Past Life in Northeast Asia at Shenyang Normal University, Quanguo Li of the State Key Laboratory of Biogeology and Environmental Geology at the China University of Geosciences, Matthew Shawkey of the Evolution and Optics of Nanostructures Group at the University of Ghent, Cuilin Zhao, again of the Paleontological Museum of Liaoning and Key Laboratory for Evolution of Past Life in Northeast Asia at Shenyang Normal University, Liliana D’Alba, also of the Evolution and Optics of Nanostructures Group at the University of Ghent, Jinkai Jiang once again of the Paleontological Museum of Liaoning and Key Laboratory for Evolution of Past Life in Northeast Asia at Shenyang Normal University, and Xing Xu of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, describe a new speciecs of Paravian Dinosaur from the Middle-Late Jurassic Tiaojishan Formation of Hebei Province, China.

The new species is named Caihong juji, where 'Caihong' means 'rainbow' in reference to the insights into the colour of Paravians that the high preservation of this specimens provides, and 'juji' means 'big crest' in reference to the large crests the specimen has on its lacriminal bones (the hind part of its snout). The species is described from a single almost complete specimen preserved on a slab and counter-slab from a layer interpreted as being 171 million years old. Besides the crests the species is distinguished by a robust dentary (jawbone) short ilium (part of the hip).

Caihong juji. Photographs of the slab (a) and counter slab (b) and line drawing (c) of the specimen based on both slabs. Photograph (d) and line drawing (e) of a composite of the rostrum of the skull and mandible exposed on the counter slab and the post-rostrum cranium exposed on the slab. Arrows indicate lacrimal crests. Question mark indicates uncertain identification. Scale bars: 10 cm a–c, 1 cm d and e. aof antorbital fenestra, cav caudal vertebra, cev cervical vertebra, dr dorsal rib, dv dorsal vertebra, ect ectopterygoid, emf external mandibular fenestra, en external naris, f feather, fu furcula, ga gastralia, hy hyoid, il ilium, is ischium, la left angular, lar left articular, lc left coracoid, lcr lacrimal crest, ld left dentary, lf left, frontal, lfe left femur, lh left humerus, lj left jugal, ll left lacrimal, lma left maxilla, lm left manus, ln left nasal, lp left pes, lpa left palatine, lpo left postorbital, lq left quadrate, lqj left quadratojugal, lr left radius, ls left scapula, lsp left splenial, lsa left surangular, lsq left squamosal, lt left tibiotarsus, lu left ulna, ma mandible, mf maxillary fenestra, o orbit, p parietal, pm premaxilla, pt pterygoid, pu pubis, rar right articular, rc right coracoid, rd right dentary, rfe right femur, rh right humerus, rm right manus, rp right pes, rpra right prearticular, rq right quadrate, rr right radius, rs right scapula, rt right tibiotarsus, ru right ulna, scl sclerotic bones, sk skull, sy synsacrum. Hu et al. (2018).

A phlylogenetic analysis suggests that the new species is a member of the Deinonychosaurs (Dromaeosaurids and Troodontids) rather than directly ancestral to the Birds though it does provide insight into a close relative of the first Birds. The specimen has a well preserved feather covering, including what appear to be densely packed melanosomes (colour cells). These would normally be indicative of a dark colour (in the absence of other colour cells, as appears to be the case, black), however those of Caihong juji resemble closely those of iridescent Birds, such as Hummingbirds, which appear to shimmer different colours when seen an angle, suggesting that this Jurassic species may have been similarly iridescent.

See also...

http://sciencythoughts.blogspot.co.uk/2017/12/ostromia-crassipes-second-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2017/06/an-enantiornithine-bird-hatchling.html
http://sciencythoughts.blogspot.co.uk/2017/01/tingmiatornis-arctica-ornithurine-bird.htmlhttp://sciencythoughts.blogspot.co.uk/2017/02/a-hesperornithiform-bird-from-late.html
http://sciencythoughts.blogspot.co.uk/2016/12/preserved-plumage-in-immature.htmlhttp://sciencythoughts.blogspot.co.uk/2016/12/tongtianlong-limosus-new-species-of.html
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Asteroid 2018 AU2 passes the Earth.

Asteroid 2018 AU2 passed by the Earth at a distance of about 1 049 000 km (2.73 times the average distance between the Earth and the Moon, or 0.70% of the distance between the Earth and the Sun), slightly after 12.15 pm GMT on Sunday 14 January 2018. There was no danger of the asteroid hitting us, though were it to do so it would not have presented a significant threat. 2018 AU2 has an estimated equivalent diameter of 6-20 m (i.e. it is estimated that a spherical object with the same volume would be 6-20 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 38 and 22 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2018 AU2. Minor Planet Center.

2018 AU2 was discovered on 13 January 2018 (the day 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 2018 AU2 implies that the asteroid was the 70th object (object U2) discovered in the first half of January 2018 (period 2018 A).  

2018 AU2 has a 899 day orbital period and an eccentric orbit tilted at an angle of 9.50° to the plane of the Solar System, which takes it from 0.96 AU from the Sun (i.e. 96% of he average distance at which the Earth orbits the Sun) to 2.68 AU from the Sun (i.e. 268% of the average distance at which the Earth orbits the Sun, and considerably more distant from the Sun than 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 the asteroid has occasional close encounters with the Earth, with the last thought to have occurred in April 2013 and the next predicted in December 2022.

See also...

http://sciencythoughts.blogspot.co.uk/2018/01/fireball-meteor-over-michigan-causes.htmlhttp://sciencythoughts.blogspot.co.uk/2018/01/asteroid-2018-at2-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2018/01/comet-c2016-a1-panstarrs-makes-its.htmlhttp://sciencythoughts.blogspot.co.uk/2018/01/asteroid-2017-yq6-passes-earth.html
http://sciencythoughts.blogspot.co.uk/2018/01/asteroid-2007-ag-passes-earth.htmlhttp://sciencythoughts.blogspot.co.uk/2018/01/comet-c2017-t1-heinze-makes-closest.html
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Friday, 19 January 2018

Dasydorylas derafshani & Dasydorylas zardouei: Two new species of Big-headed Flies from Iran.

Big-headed Flies, Pipunculidae, are True Flies, Diptera, that gain their name from their large eyes, which cover most of their heads. Adult Big-headed flies feed on Honeydew, a sugary secretion produced by Aphids, but the larvae are parasitoids, maturing inside the bodies of other Insects (typically Crane Flies or Leafhoppers), which they consume from the inside as they grow. Because of this habit they are considered to be potentially useful biocontrol agents for Insect pest species.

In a paper published in the European Journal of Taxonomy on 26 October 2017, Behnam Motamedinia of the Department of Plant Protection at the University of Zabol, and the Plant Protection Research Department at the South Agricultural and Natural Resources Research and Education Center, Christian Kehlmaier of the Senckenberg Natural History Collections Dresden, Azizollah Mokhtari and Ehsan Rakhshani, also of the Department of Plant Protection at the University of Zabol, and Ebrahim Gilasian of the Insect Taxonomy Research Department of the Iranian Research Institute of Plant Protection, describe two new species of Big-headed Flies from Iran.

The first new species is named Dasydorylas derafshani, in honour of Hossein Ali Derafshan, who collected the specimens from which the species is described. The species is described from three male specimens, collected in Zabol County in Sistan-o Beluchestan Province. These are 3.3-3.7 mm in length, and silvery grey in colour with large red eyes.

Dasydorylas derafshani, male specimen in lateral view. Scale bar is 1 mm. Motamedinia et al. (2017).

The second new species is named Dasydorylas zardouei, in honour of Maryam Zardouei who collected the specimens from which the species is described. The species is described from four male and two female specimens from Kermanshah Province. These are 3.1-3.5 mm in length and are dark grey in colours with orange eyes.

Dasydorylas zardouei, female specimen in lateral view. Scale bar is 1 mm. Motamedinia et al. (2017).

See also...

http://sciencythoughts.blogspot.co.uk/2017/08/simulium-littopyga-simulium-littosocius.htmlhttp://sciencythoughts.blogspot.co.uk/2016/10/thevenetimyia-spinosavus-new-species-of.html
http://sciencythoughts.blogspot.co.uk/2016/10/ceropegia-sandersonii-flower-mimicking.htmlhttp://sciencythoughts.blogspot.co.uk/2016/08/atherigona-reversura-bermudagrass-stem.html
http://sciencythoughts.blogspot.co.uk/2016/07/psectrosciara-fossilis-dung-midge-in.htmlhttp://sciencythoughts.blogspot.co.uk/2015/11/fossil-bee-flies-from-dominican.html
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Eruptive activity on the Volcán Arrau peak of the Nevados de Chillán Volcanic Complex in Central Chile.

The Observatorio Volcanológico de Los Andes del Sur of the Servicio Nacional de Geología and Minería in Chile have reported observing activity on the Volcán Arrau peak of the Nevados de Chillán Volcanic Complex. This activity was first observed on 21 December 2017, when a flight over the area observed a fissure within the central crater of the volcano. A second flight on 9 January identified a new lava dome (mound produced by the slow extrusion of viscous lava) on the site of the fissure. This was accompanied by gas and water vapour emissions and a surface temperature of about 480°C.

Emissions from Nevados de Chillán on 9 January 2017. Observatorio Volcanológico de Los Andes del Sur/Municipio de Pinto/Twitter.

The Nevados de Chillán Volcanic Complex comprises three main overlapping volcanoes, Cerro Blanco (or Volcán Nevado),  Volcán Viejo (or Volcán Chillán), and Volcán Nuevo, plus a number of smaller vents, including Santa Gertrudis, Gato, Cerro Blanco, Colcura, Calfú Pichicalfú, Baños, Shangri-La, Nuevo, Arrau, Viejo, Chillán y Pata de Perro, Las Lagunillas and Parador. These volcanoes form an approximate line running roughly northwest to southeast, which first emerged during the Late Pleistocene or Early Holocene.

The approximate location of the Nevados de Chillán Volcanic Complex. Google Maps.

Like other volcanoes in the Andes, the Nevados de Chillán Volcanic Complex is fed by the subduction of the Nazca Plate beneath the South American Place along the west coast of the continent. As the Nazca Plate sinks into the Earth it passes under South America, and at the same time is partially melted by the heat and pressure of the planet's interior. More volatile elements in the melted magma to rise up through the overlying South American Plate, fuelling the volcanoes of the Andes.

The subduction of the Nazca Plate beneath the South American Plate, and how it causes Earthquakes and volcanoes. Pacific Earthquake Engineering Research Center.

See also...

http://sciencythoughts.blogspot.co.uk/2017/12/landslide-kills-at-least-five-in.htmlhttp://sciencythoughts.blogspot.co.uk/2017/11/magnitude-49-earthquake-in-petorca.html
http://sciencythoughts.blogspot.co.uk/2017/10/magnitude-54-earthquake-in-el-loa.htmlhttp://sciencythoughts.blogspot.co.uk/2017/09/magnitude-58-earthquake-off-coast-of.html
http://sciencythoughts.blogspot.co.uk/2017/07/magnitude-51-earthquake-in-antofagasta.htmlhttp://sciencythoughts.blogspot.co.uk/2017/01/wildfires-kill-at-least-eleven-in-chile.html
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