Wednesday, 26 November 2014

Asteroid 2014 WH6 passes the Earth.

Asteroid 2014 WH6 passed by the Earth at a distance of 11 200 000 km (29.13 times the average distance between the Earth and the Moon, or 7.5% of the average distance between the Earth and the Sun), slightly before 5.05 pm GMT on Monday 24 November 2014. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2014 WH6 has an estimated equivalent diameter of 21-65 m (i.e. it is estimated that a spherical object with the same volume would be 21-65 m in diameter), and an object of this size would be expected to break up in the atmosphere between 22 and 4 km above the ground, with only fragmentary material reaching the Earth's surface.

The calculated orbit of 2014 WH6. JPL Small Body Database Browser.

2014 WH6 was discovered on 17 November 2014 (seven days before its closest approach to the Earth) by the University of Hawaii's PANSTARRS telescope on Mount Haleakala on Maui. The designation 2014 RT17 implies that it was the 444th asteroid (asteroid T17) discovered in the first half of September 2014 (period 2014 R).

While 2014 WH6 occasionally comes near to the Earth, it does not actually cross our orbital path. It has an elliptical 1627 day orbit, at an angle of 14° to the plane of the Solar System, that takes it from 1.04 AU from the Sun (1.04 times the average distance at which the Earth orbits the Sun), slightly outside our orbit, to 4.37 AU from the Sun, (4.37 times the distance at which the Earth orbits the Sun, and almost three times the average distance at which the planet Mars orbits the Sun). As a Near Earth Object that remains strictly outside the orbit of the Earth it is classed as an Amor Family Asteroid.

See also...

Asteroid 2014 WF201 passed by the Earth at a distance of 2 398 000 km (6.24 times the average distance between the Earth and the Moon, or 0.016% of the average distance...

The Irish Astronomical Association has reported a fireball over County Antrim in Northern Ireland at about 5.30 pm GMT on Tuesday 18 November 2014. The meteor was reportedly brighter than the Moon, and...

In 1984 palaeontologists David Raup and Jack Sepkowski of the Department of Geophysical...

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A new species of Vetulicolian from the Early Cambrian of Kangaroo Island, South Australia.

Vetulicolians are an enigmatic group of Cambrian fossils known from the Chengjiang and Guanshan biotas of South China, Sirius Passet in Greenland and the Burgess Shale in western Canada. They have segmented bodies that caused them to be initially classified as Arthropods, but have never been found to have limbs, and the discovery of structures interpreted as gill slits, a mesodermal skeleton and a possible notochord have led to them being interpreted as Chordates (the group of animals that includes Vertebrates) in most modern studies, although opinions on how they might be related to other Chordates varies. 

In a paper published in the journal BMC Evolutionary Biology on 21 October 2014, Diego García-Bellido and Michael Lee of the School of Earth and Environmental Sciences and Environment Institute at the University of Adelaide and Earth Sciences Section at the South Australian Museum, Gregory Edgecombe of the Natural History Museum in London, James Jago of the Barbara Hardy Institute at the University of South Australia, James Gehling, also of the School of Earth and Environmental Sciences & Environment Institute at the University of Adelaide and Earth Sciences Section at the South Australian Museum and John Paterson of the Division of Earth Sciences at the University of New England describe a new species of Vetulicolian from the Early Cambrian Emu Bay Shale Konservat-Lagerstätte on Kangeroo Island in South Australia.

The new species is named Nesonektris aldridgei, where ‘Nesonektris’ means ‘island swimmer’ and ‘aldridgei’ honours the late Dick Aldridge, who led attempts to resolve the affinities of Vetulicolians. The species is described from over 150 specimens, the largest of which is 125 mm in length, but with incomplete specimens that suggest a maximum length of about 170 mm. The specimens have a roughly square forward section, with an oral margin connected to dorsal and ventral keels, a narrow lateral groove, and no trace of any gills. The rear part of the fossils comprises a series of seven segments apparently supported by a rod-like structure, with two lobes on the terminal segment connected by a flat notch.

The Early Cambrian Vetulicolian Nesonektris aldridgei. (A–C) Specimen with distal end of posterior body region (S4–S7) folded over itself, anterior towards left; (A) part, anterior rim exposed by preparation (arrow points to cuticle wall under the rod); (B) counterpart, with severed notochord (detail in Figure 2B); (C) camera lucida drawing, grey indicates sediment infill; (D) nearly complete specimen, only lacking one side of anterior region body; (E) nearly complete specimen; (F) nearly complete but folded specimen; showing fold on anterior region (oblique arrow) and continuous connection between anterior and posterior body regions along the dorsal margin (vertical arrow); (G) reconstruction; abbreviations: dk = dorsal keel; eb = epibionts; ism = intersegmental membrane; lg = lateral groove; nc = notochord; om = oral margin; vk = ventral keel; S1–S7 = posterior body region segment number; scale bars, 5 mm. García-Bellido et al. (2014).

The structure interpreted as a notochord in Vetulicolians, upon which the interpretation of them as Chordates is based, is problematic as this structure is disproportionately large compared to the body, and indeed would be exceptional compared to the notochords of even the largest modern Chordates. It has been suggested that this structure may instead be a gut or coelomic cavity, however a gut of this size would also be highly disproportionate to the size of the body.

The ‘notochord’ of several specimens of Nesonektris aldridgei appears to be made up of a series of offset blocks. García-Bellido et al. consider this to be similar to the situation seen in Cephalochordates (Lancets), larval Urochordates (Sea Squirts) and some larval Vertebrates, notably Lampreys, in which the notochord consists of a series of stacked disks in a thin sheath, which can decpme disarticulated as the dead animal decays, supporting the Chordate hypothesis for the affinities of Vetulicolians.

(E) Detail of displaced notochord in specimen of Nesonektris aldridgei, with small offsets at regular intervals (white arrowheads) corresponding to discs and larger displacement into blocks of discs (yellow arrowheads); (F) partially decayed Hagfish notochord, showing displacement of discs. (E) Scale bar 5 mm. García-Bellido et al. (2014). (F) Scale Bar 2 mm. Robert Sansom in García-Bellido et al. (2014).

García-Bellido et al. also consider that the body-plan of Vetulicolians is very similar to that of larval Tunicates, with a similar two-part body, comprising a front portion with a terminal mouth, and a rear tail portion supported by a notochord, and suggest that the two groups are probably closely related, a theory supported by a computer generated phytogenic analyses of Chordate groups.

Phylogenetic position of Vetulicolians within Deuterostomia. Maximum parsimony analysis strict consensus of 65 cladograms (Vetulicolians collapsed into a single terminal. Blue box encapsulates phylum Chordata; daggers and red branches represent extinct taxa known only from fossils. Parsimony-bootstrap values (above branches) and Bremer support (below) are shown for analyses including/excluding the non-Vetulicolian fossil taxa. García-Bellido et al. (2014).

García-Bellido et al. suggest that the common ancestor of Tunicates and Vetulicolians may have been a free-swimming animal with a thick cuticle and a large pharynx used for filter feeding. The Tunicates subsequently changed their lifestyle to become attached benthic animals during their adult phase, while the Vetulicolians evolved into larger, free swimming filter feeders, a niche otherwise unoccupied in the Cambrian. These animals would have been sightless and reliant on a thick cuticle for protection.

Artist’s impression of Nesonektris aldridgei in life. Katrina Kenny in García-Bellido et al. (2014).

See also…

The Vetulicolians are are group of organisms known from Cambrian deposits at a number of sites around the world. They Have segmented bodies superficially resembling those of Arthropods, but lack any visible limbs. Since palaeontologists and biologist theorize that the earliest Arthropods lacked limbs, having evolved from...

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Tuesday, 25 November 2014

The origin of the ‘King of Flowers’.

The Domestic Tree Peony, Paeonia suffruticosa, has a long history of cultivation in China, where records of the plant growing in gardens go back at least 1400 years. Domestic Tree Peonies are noted for their beauty and fragrance, and are known as the ‘King of Flowers’ in China. However the precise origin of the domestic Tree Peony is obscure, with most experts believing that it is a hybrid of two or more of the wild Tree Peony species found in China, but with no consensus as to which plants might be involved.

In a paper published in the Proceedings of the Royal Society: SeriesB, Biological Sciences on 5 November 2014, a team of scientists led by Shi-Liang Zhou of the State Key Laboratory of Systematic and Evolutionary Botany at the Institute of Botany at The Chinese Academy of Sciences describe the results of a genetic study of Paeonia suffruticosa and the nine wild Tree Peony species found in China, in order to determine the relationships of the domestic plant.

The ‘King of Flowers’, Paeonia suffruticosa, at Prague Botanic Garden. Karel Jakubec/Wikimedia Commons.

Zhou et al. found that Paeonia suffruticosais a hybrid of at least five wild species, Paeonia cathayana, Paeonia rockii, Paeonia qiui, Paeonia ostii and Paeonia jishanensis, with most of the cultivars obtained by hybridizing female Paeonia cathayana flowers with males of another species, though sometimes other plants had been used as the female, and many cultivars had been achieved by further hybridization.

Zhou et al. further note that all the wild Tree Peony species involved come from central China, the area in which the domestic plant was first cultivated, and that the majority are now rare or endangered. In particular they note that only a single specimen of Paeonia cathayana, the species that appeared to contribute the most to the origin of the domestic plant, could be found growing in the wild, in the mountains to the south of Louyang. Paeonia ostii also seemed to be reduced to a single wild specimen, this time on a cliff in central Anhui Province, and Paeonia qiui was found only in a handful of small populations in western Hubei Province. Paeonia jishanensis still has several relatively large populations, but this species is known to reproduce vegitatively (non-sexually), so it is unclear how genetically diverse these populations are (low genetic diversity populations can be extremely vulnerable to disease, and apparently large and healthy populations are sometimes wiped out suddenly). Only one species, Paeonia rockii, is still relatively widespread, being found across a large area of central and western China, but this is widespread population is largely composed of widely scattered very small populations and individuals, making this species also vulnerable.

The distribution of nine wild tree peony species. (1) Paeonia ludlowii; (2) Paeonia delavayi; (3) Paeonia decomposita; (4) Paeonia rotundiloba; circle, Paeonia rockii; diamond, Paeonia jishanensis; square, Paeonia ostii; triangle, Paeonia qiui; hexagon, Paeonia cathayana. Zhou et al. (2014).

Approximately one tenth of the dry land surface of the Earth has now been converted to agricultural purposes by Humans, and that while this has benefitted us enormously, it has come at great cost to many wild species, particularly the progenitors (wild ancestors) of most of our crops, which for the most part formerly grew in the best areas for growing their domestic relatives. This is known to present food security problems for Human populations, as domestic crops tend to be less genetically diverse and therefore more vulnerable to disease than their wild relatives, and the loss of these wild relatives reduces the available genetic diversity that might be needed to breed crops resilient to as yet unknown threats. Zhou et al. observe that in addition to this known problem with agricultural plants, the widespread cultivation of ornamental plants in parks and gardens presents an additional threat to biodiversity, that should also be a focus for botanists and conservationists.

See also… The impact of an invasive native shrub on semi-arid cattle rangelands in Zimbabwe. 
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Supplejack leaves from the Early Eocene of Patagonia.

Australia and Antarctica are remote from one-another today, but share many common floral and faunal elements. This is because they are both former parts of the ancient continent of Gondwana, and along with Antarctica were the final parts of the ancient supercontinent to break apart. Antarctica today is a frozen continent, with life only clinging on around its coasts, but in the warmer climate of the Eocene supported a far richer fauna and flora, and provided a land bridge between Australia and South America.

In a paper published in the journal Palaeontologica Electronicaon in October 2014, Raymond Carpenter of the School of Earth and EnvironmentalSciences at the University of Adelaide, Peter Wilf of the Department of Geosciences at Pennsylvania State University, John Conran of the AustralianCentre for Evolutionary Biology and Biodiversity at the University of Adelaide and Rubén Cúneo of the Museo Paleontológico Egidio Feruglio of the Consejo Nacionalde Investigaciones Científicas y Técnicas describe the discovery of leaves attributed to a Supplejack plant from the Early Eocene of Patagonia.

Supplejacks, Ripogonaceae, are today found only in Australia, New Zealand and Papua New Guinea. They are prickly vines or shrubs found in the understory of rainforests, and produce robust abundant leaves, which they shed each year, giving them good potential for producing fossils. Genetic studies have shown Supplejacks to be closely related to Chilean Bellflowers, Philesiaceae, which have similar habits but which are restricted to the temperate Valdivian rainforests of Chile.

The new species is named Ripogonum americanum, as it was the first member of the group recorded from the Americas. It is described from two specimens, one leaf preserved as part and counterpart, the other as a single sided impression only. Both were recovered from the Laguna del Hunco caldera-lake beds of Chubut in Argentinean Patagonia, which has produced a varied palaeorainforest flora, and which contains volcanic tuff layers which have enabled the dating of the fossils to about 52.22 million years old (Early Eocene).

(1) Ripogonum americanum from Laguna del Hunco and (2)extant Ripogonum album from Queensland, Australia. Note that although the petiolar region is not preserved, a decurrent pair of suprabasal secondary veins andbasal pair of submarginal veins are clearly visible. Note also the tertiary veins, higher order reticulate venation, veinloops between the secondary vein pairs, and looped ultimate veins at the margins (arrowed). Note virtually identical details on the recent leaf to those visible in the fossil. Scale bars equal 10 mm. Carpenter et al. (2014).

Previous fossils attributed to Ripogonum have been found in Tasmania and New Zealand, but this is the first specimen from the Americas. The Laguna del Hunco  deposits have also yielded specimens attributed to the Philesiaceae, suggesting that the two groups were living alongside one-another at the time, and that Ripogonum had a distribution that ranged from Patagonia across Antarctica to Australia and New Zealand.

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Tulips of the genus Amana are found in eastern Asia. They are very similar to the Tulips of Western Asia and Europe, which are placed in the genus Tulipa, differing only in the presence of bracts on the upper part of the flowering stem, and not all botanists have recognised the two genera as distinct. However modern genetic studies appear to support the separation of the two groups, as closely related but distinct genera with different geographical...
Turmeric (Curcuma) plants are members of the Ginger Family (Zingiberaceae) native to India, southern China, Southeast Asia, Indonesia, Papua New Guinea and northern Australia. Several species are grown for use as a spice or dye, and the more colourful species are popular garden plants in tropical areas, though they need constant warm temperatures and high rainfall to thrive. The plants can reproduce both sexually by flowering and asexually by means...
Peruvian Lilies, Alstroemeriaceae, are a small group of flowering plants found across Central and South America, the islands of the Caribbean and the Falklands. The are members of the Lily order, Liliales, and have relatives in Australia and New Zealand...
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Melbourne woman swallowd by 3 m sinkhole.

A woman had to be rescued by firefighters after being swallowed by a sinkhole while hanging out washing in her garden on Tuesday 25 November 2014. Christina Beaumont fell into the hole at about 11.30 am local time in the Springvale South area of the city, and had to tread water until the rescuers arived at 12.30, allerted by a neighbour who had heard her cries for help. The whole was less than a meter wide, but around three meters deep and flooded in its bottom part, while sediment continued to fall from the sides of the hole onto Ms Beaumont, who is being treated for shock.

The sinkhole on the property at Springvale South, Melbourne.

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. Potash, a potassium salt, is readily soluble and can be dissolved quickly if water gains access to deposits, leading to the rapid formation of sinkholes.

On this occasion investigators from Greater Dandenong City Council have determined that the sinkhole occured at the site of an old well on the property, which had been improperly sealed off.

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A three-story house in Swansea Head, New South Wales, has had to be evacuated after a sinkhole opened up beneath it on Tuesday 27 May 2014. The hole is...

Five homes have been evacuated following a landslide at Bilgola Beach on the Barrenjoey Peninsula in northern Sydney, New South Wales. The incident occurred early on the morning of Tuesday 13 May 2014, and was made worse when a fire truck arrived at...
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X-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 Asia around 700 000 years ago and by 200 000 years ago spread across Asia and into Europe and across the Bering Strait into North America, where they hybridized with the Columbian Mammoth Mammuthus columbi. They are believed to have been the last surviving species of Mammoth, persisting to as late as 3700 years ago on Wrangel Island, off the northeast coast of Siberia (with some claims of even more recent specimens). As a widespread and apparently numerous species living in the recent past they have left an extensive fossil record, primarily of isolated teeth and bones, but also including a number of mummified and frozen specimens, trapped within the Arctic permafrost. These have allowed a number of detailed anatomical and molecular studies of the Woolly Mammoth, although many were excavated in the nineteenth and early twentieth centuries, and have subsequently degraded due to poor storage facilities, preventing the application of the most modern methods to these specimens.

In a paper published in the Journal of Paleontology in July 2014, a team of scientists led by Daniel Fisher of the Museum of Paleontology at the University of Michigan describe the results of a series of X-ray Computed Tomography studies of two recently discovered Woolly Mammoth calves from permafrost in the Siberian Arctic.

The first specimen, named Lyuba, was found in May 2007 by on a bank of the Yuribei River on the Yamal Peninsula, where it is believed to have been deposited by an ice-melt flood the previous spring. When found it was almost intact, having lost only its hair and nails, however it was transported to a nearby village where it was partially scavenged by domestic Dogs, losing part of the tail and right ear, before being acquired by the Shemanovskiy Museum and Exhibition Center in Salekhard in the Yamalo-Nenets Autonomous Okrug of the Russian Federation. Here the specimen was found to be partially dehydrated, having lost approximately half of its expected water content, and found to be female by examination of the urogenital tract, and subsequent DNA analysis.

Lyuba’s body was found to have been acidified, probably by colonization of the corpse by lactic acid-producing Bacteria, leading to the degradation of much of the connective tissue (collagen). The facial region was found to contain numerous masses of vivianite (hydrated iron phosphate). Examination of Lyuba’s teeth was able to find a neonatal line (produced at the time of birth) followed by 30-35 daily growth increment lines, setting her age at the time of death at 30-35 days. She appears to have been healthy and well fed at the time of her death. An isotopic analysis of the age of the body suggested an age of about 41 800 years.

Lyuba was subjected to a full CT scan, then examined endoscopically through two holes drilled in her left side. She then underwent two necropsy sessions, in which her body was thawed, partially dissected then refrozen. In the first the teeth were removed from the left side of the face, and portions of the large and small intestine were also extracted. In the second the pleural and abdominal cavities were examined. At this point it was determined by the Shemanovskiy Museum that the body would need to be treated chemically to prevent further decomposition, and allowed to dehydrate fully.

Fisher et al. were unable to access the original CT scans of Lyuba made at the Shemanovskiy Museum before chemical treatment. However they were able to take the body to the GE Healthcare Institute in Waukesha, Wisconsin, where it was possible to scan the Mammoth’s head and neck and a portion of the right forelimb and (separately) her pelvic region and left hind limb (the entire Mammoth was too large to fit into the scanning equipment at Waukesha). A complete scan of the Mammoth’s body was later made at the Nondestructive Evaluation Laboratory of the Ford Motor Company in Livonia, Michigan (as far as Fisher et al. are aware this is the first time a Mammoth has undergone a complete full-body scan in this way). Unfortunately industrial scanners like the one at Livonia are slower than medical models, and only seventeen hours were available for the scans on Lyuba, so the resolution achieved was not as high as hoped. Micro CT scans of the extracted teeth were carried out at the University of Michigan Dental School in Ann Arbor, Michigan.

Lyuba was already known to have significant sediment lodged within her trunk. Her oral cavity (mouth) was also filled with sediment, although this matched the bank sediment at the site by the Yuribei River where she was found, so it is assumed that this was emplaced during the recent transportation of the body. The second necropsy carried out on Lyuba was able to determine that her lungs had collapsed, and that larger bronchial cavities were filled with a bright blue powder identified as vivianite with some clay minerals. The CT scans revealed that Lyuba’s trachea was also filled with material which had the same density as the material in both the trunk and lungs, suggesting that all three are the same.

Fisher et al. suggest that Lyuba died after inhaling mud which blocked her trachea and the front part of the bronchial system in her lungs, preventing her from breathing and leading to suffocation; this matches the distribution of sediment seen in the trachea and lungs and the collapse of the other lung tissue (in the alternative scenario, drowning, sediment would have spread throughout the lungs, which would not have collapsed. It is impossible to assess where this happened, as the body had been transported prior to its discovery, but fine-grained vivianite is typical of lake-bottom sediments.

Aspirated sediment in the Mammoth calf Lyuba, sediment with a radiodensity in the range of bone can be traced from the pharyngeal region,through the trachea, and into the lung bronchi (from the Ford scan). Fisher et al. (2014).

The first vivianite detected on Lyuba was found on her left side, which was the side she was laying on when discovered, wher a number of circular pit where filled with bright blue material. This is interpreted to have been caused by fungal growth, which has previously been documented on a number of other specimens of similar age, including the ‘Blue Babe’ Steppe Bison mummy and the Tyrolian iceman ‘Otzi’. However vivianite was also found in nodules throughout the facial region of Lyuba, and within the diaphyses of her long bones (the growing ends of the long bones in a young mammal), where a better explanation was needed.

Fisher et al. suggest that this is connected closely to the manner of Lyuba’s death. If she did asphyxiate on lake bottom sediments, then it is likely that she was in a cold, wet environment suffering from oxygen deprivation immediately prior to death. Mammals in such circumstances have a ‘diving reflex’, whereby blood is withdrawn from the skin and extremities, but the supply increased to the face and brain, thereby keeping the animal alive as it tries to escape its predicament. Vivianite is an iron-phosphorous mineral, and needs a supply of both elements to form. In the case of the facial nodules the iron comes from blood pumped to the head as Lyuba struggled for her life, while the phosphorus comes from the dissolution of bone tissue by the action of lactic-acid forming Bacteria after her death. In the case of the long bone diaphyses the iron would have come from bone marrow, which is particularly rich in iron in these areas of bone growth.

Larger elements of Lyuba’s appendicular skeleton (without maniand pedes) extracted from the Ford scan: (1) radiodense nodules withindeveloping trabecular spaces in long bones are probably vivianite crystalsformed from bone-derived phosphate and blood- and marrow-derived iron;bones show radiodensity disparity between diaphyses and epiphyses; rightlateral aspect, hind limbs on left (right ahead of left) and forelimbs on right(right ahead of left); (2) left humerus in anterior aspect,diaphysis (green) segmented separately from epiphyseal ossifications(labeled); (3) segmented radiodense nodules show through cortical bone of diaphysis (humerus unsegmented in this image so that nodules show through);common scale for 2 and 3. Fisher et al. (2013).

Lyuba’s ribcage had been laterally compressed (squashed from the sides) after death, with the greatest amount of deformation occurring on the left side. Her backbone is intact, and appears to be in life position. Her skull is also slightly deformed and compressed, which may have been aided by partial dissolution of the bone by lactic acid.

The second Mammoth calf, Khroma, was found preserved in situ, upright in permafrost near the Khroma River in northern Yakutia in October 2008, and subsequently excavated and shipped to the Mammoth Museum at the Institute of Applied Ecology of the North at North-East Federal University in Yakutsk in the Sakha Republic. At the time of discovery it had been partially eroded from the sediment, and parts of the head trunk and shoulders scavenged by Ravens and (possibly) Arctic Foxes. Thus, while in generally good condition, the body had lost much of the trunk, the flesh from the head, the fatty tissue from the back of the neck (where a fatty hump would be expected) and the heart and lungs. DNA analysis showed Khroma to be female, which was subsequently confirmed by CT scanning of the urogenital tract. A necropsy revealed she had abundant subcutaneous fat, and undigested milk in her stomach. It was not possible to determine the age of Khroma isotopically, suggesting she died more than 45  000 years ago.

Khroma was also subjected to two rounds of CT scanning, first at the Centre Hospitalier Universitaire de Clermont-Ferrand, then at the CentreHospitalier Emile Roux in Le Puy-en-Velay, both in France. Her teeth were also extracted and micro CT scanned at the at the University of Michigan Dental School in Ann Arbor, Michigan.

Examination of Khroma’s teeth enabled the detection of a neonatal line, followed by at least 52 daily growth increment lines, although these were somewhat unclear, leading Fisher et al. to conclude that she was 52-57 days old at the time of her death.

Khroma’s age, determined from her right dP3: (1) right image shows lingual aspect of a slab cut from the right dP3, anterior to the left; (2) enlargedview of the anterior root in 1; the dark line running vertically, parallel to the pulp cavity surface, is the neonatal line (NnL); (3) photomicrograph of a thin sectionof the anterior root, with pulp cavity (pc) surface at right, neonatal line (NnL) at left, and 52 or more daily dentin increments (small white dots) between them; (4) enlargement of area designated in (3), showing increments for last 18 days of life. Fisher et al.estimate Khroma’s age at death as 52–57 days. Fisher et al. (2013).

Elephants walk on a thick pad of fat with a thick layer of skin over it. The distal phalanges (bones at the tips of the toes) are believed to help distribute weight evenly within this structure, though exactly how this works is unclear. In African Elephants only the third and fourth toes have ossified (bone) distal phalanges, with these elements in the other toes being cartilage, while in Asian Elephants the distal phalanges of toes two, three and four are ossified. Attempts to resolve the number of ossified distal phalanges in Mammoths have been, to date, unsuccessful, largely as the limb tips are seldom preserved intact.

Khroma was preserved with her feet undamaged, making analysis of the ossification state in the distal phalanges a possibility. Unfortunately no ossified distal phalanges could be detected, nor was it possible to detect ossification in the metatarsal-phalangeal sesamoid (known to ossify in Woolly Mammoths), suggesting that Khroma was too young at the time of death for complete ossification of all the bones in the foot to have occurred. However it was possible to detect the synovial capsules in the foot (fluid filled capsules that form between bone-bone joints in Mammals, but not bone-cartilage joints), as these had lost their fluid but filled with (distinctly less dense) air. This suggests that the second, third, fourth and fifth distal phalanges may have ossified.

Khroma’s left hind foot: (1) lateral aspect, anterior to left,showing nucleation sites and epiphyseal ossification center on calcaneumtuber at right; (2) anterior aspect; (3) anterior aspect, synovial joint capsules ondigits, light blue; (4) anterior aspect, non-terminal joint capsules light blue andterminal joint capsules purple. Abbreviations: Ast., astragalus; Cal., calcaneum; Cub., cuboid; Ect., ectocuneiform; Ent., entocuneiform; IP, intermediate phalanx; Mes., mesocuneiform; MT, metatarsal; MT I, metatarsal I (red); MT V, metatarsal V (blue diaphysis); PP, proximalphalanx. Separate scales for 1 and 2; common scale for 3 and 4. Fisher et al. (2013).

Khroma’s skeleton was more damaged than Lyuba’s, with some of the ribs broken by recent scavenging, and a break between the seventh and eighth thoracic vertebrae, which occurred at about the time of death. Khroma is thought to have died of sediment inhalation in a similar way to Lyuba, but this break suggests a much more violent setting (the backbones of even very small Elephants are quite robust). Fisher et al. suggest that she may have been caught in a mud flow or bank collapse, which caused a significant lateral impact as well as burying her and preventing breathing.

 Khroma’s ribcage in right lateral aspect (interruption of rib sequence caused by break in vertebral column). Fisher et al. (2013).

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Fossil Dwarf Elephants are known from a number of small islands around the world; this is not altogether surprising, dwarfism is common in populations of animals cut of on small islands (as is giantism). Animals in such environments often need to adapt to different niches to those they inhabit on larger land-masses, but are able to do so due to lack of competition, since there...

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Elephants have a long and well understood fossil record, but this can usually only tell us about the physical attributes of Elephants, i.e. their...

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Asteroid 2014 WF201 passes the Earth.

Asteroid 2014 WF201 passed by the Earth at a distance of 2 398 000 km (6.24 times the average distance between the Earth and the Moon, or 0.016% of the average distance between the Earth and the Sun), slightly after 11.35 am GMT on Monday 24 November 2014. There was no danger of the asteroid hitting us, though had it done so it would have presented only a minor threat. 2014 WF201 has an estimated equivalent diameter of 18-57 m (i.e. it is estimated that a spherical object with the same volume would be 18-57 m in diameter), and an object of this size would be expected to break up in the atmosphere between 22 and 7 km above the ground, with only fragmentary material reaching the Earth's surface.
 The calculated orbit of 2014 WF201. JPL Small Body Database Browser.

2014 WF201 was discovered on 23 November 2014 (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 2014 WF201 implies that it was the 5031stasteroid (asteroid F201) discovered in the second half of November 2014 (period 2014 W).

2014 WF201 has a 426 day year orbital period and an eccentric orbit tilted at an angle of 8.5° to the plane of the Solar System, which takes it from 0.987 AU from the Sun (i.e. 98.7% of the average distance at which the Earth orbits the Sun) to 1.23 AU from the Sun (i.e. 123% of the average distance at which the Earth 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 2014 WF201 and the Earth are fairly common, with the last thought to have occurred in July this year next one predicted for June 2021.

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