Sunday, 25 June 2017

Brachylophus gau: A new species of South Pacific Iguana from Gau Island, Fiji.

Three living and one extinct species of South Pacific Iguana, Brachylophus spp., are known from the islands of Fiji, as well as a single species of a second genus Lapitiguana, a much larger, but also now extinct, Lizard. These Iguana’s are thought to have lived in isolation in the island group for around 40 million years, with their closest living relatives found in the deserts of the southwestern United States. Each species of South Pacific Iguana is recorded only from a single island, but several other islands of Fiji are known to host Iguanas, suggesting that either some of these species have greater ranges than has previously been recorded, or that there are undiscovered species of Iguana in the islands.

In a paper published in the journal Zootaxa on 6 June 2017, Robert Fisher of the San Diego Field Station of the U.S. Geological Survey’s Western Ecological Research Center, Jone Niukula of The National Trust of Fiji, Dick Watling of NatureFiji-MareqetiViti, and Peter Harlow of the Taronga Conservation Society, describe a new species of South Pacific Iguana from Gau Island, Fiji.

The new species is named Brachylophus gau, the Gau Iguana, and is distinguishable from all other members of the genus by the colouration of the throat, which is a plain green in both sexes. The species has a mean snout-vent length (length excluding the tail of 149.2 mm, and a maximum of 153 mm (the total length, including the tail, was not used as several specimens showed signs of having lost and regrown their tails, which will reduce this). These Iguanas are bright green in colour, shading from avocado green on their backs to sulphur green on their bellies, with a series of blue-grey bands on their body and tail. 

Illustration of the male, left, and female, right, of Brachylophus gau. The painting is from photographs of these specimens and others from life. Measurements to scale within illustration. The male is missing later 2/3 of tail, but tail drawn here based on photos from other males. Cindy Hitchcock in Fisher et al. (2017).

Although this species had not previously been recorded, examination of museum specimens found two additional examples of this Iguana in the collection of the Natural History Museum in London. These were donated by John MacGillivray of the H.M.S. Herald in 1855, with a recorded location only of ‘Fiji’. Examination of the MacGillivray’s private journal shows that the H.M.S. Herald did indeed visit Gau Island on 12 and 27 September 1854, where MacGillivray shot Green Iguanas hidden in the foliage of the Ivi (Tahitian Chestnut) Tree.

See also...

http://sciencythoughts.blogspot.co.uk/2016/12/sceloporus-goldmani-new-populations-of.htmlhttp://sciencythoughts.blogspot.co.uk/2016/08/anolis-landestoyi-chameleon-like-anole.html
http://sciencythoughts.blogspot.co.uk/2016/04/tropidurus-sertanejo-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2015/07/babibasiliscus-alxi-casquehead-lizard.html
http://sciencythoughts.blogspot.co.uk/2015/01/a-new-species-of-twig-anole-from-panama.htmlhttp://sciencythoughts.blogspot.co.uk/2014/11/four-new-species-of-treerunner-from.html
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Sichuan landslide feared to have killed over 100 people.

Over a hundred people are feared to have died following a landslide in a remote mountain village in Mao County in Sichuan Province, China, on Saturday 24 June 2017. The landslide struck the village of Xinmo at about 6.00 am local time, sweeping away all of the about forty homes in the village and damming a nearby river. So far only three survivors have been found, a couple and their two month old baby, all of whom are being treated in a nearby hospital, while 25 bodies have been recovered and 93 people are missing. A further 15 residents of the village have been confirmed safe as they were staying outside the community when the landslip occurred. Over three thousand rescue workers, assisted by specially trained dogs, are involved in the ongoing search, though there is thought to be little hope of finding any more survivors.

Rescue workers at the scene of the 24 June 2017 Sichuan landslide. Reuters.

The incident is reported to have been triggered by heavy rainfall in the area. Landslides are a common problem after severe weather events, 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. The climate of Sichuan Province is heavily influenced by the Asian Summer Monsoon, with heavy rainfall common in the summer. Xinmo is located on the province's Northern Plateau, where landslides are a common problem due to a mountainous terrain and limited vegetation cover.

See also...

http://sciencythoughts.blogspot.co.uk/2016/10/fifteen-confirmed-deaths-following.htmlhttp://sciencythoughts.blogspot.co.uk/2015/06/landslide-causes-tsunami-on-daning.html
http://sciencythoughts.blogspot.co.uk/2015/04/injuries-reported-following-earthquake.htmlhttp://sciencythoughts.blogspot.co.uk/2015/03/magnitude-42-earthquake-in-guizhou.html
http://sciencythoughts.blogspot.co.uk/2014/11/five-dead-after-magnitude-63-earthquake.htmlhttp://sciencythoughts.blogspot.co.uk/2014/10/at-least-one-person-dead-after.html

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Friday, 23 June 2017

Sedum danjoense: A new species of Succulent Plant from the Danjo Islands, Japan.

The Danjo Islands are a small group of uninhabited islands located about 170 km to the west of Kyushu in the South China Sea. The uninhabited islands have a total surface area of only 4.38 km², but are home to a range of organisms found nowhere else, including a subspecies of Snake, thirteen unique Land Snail species and a species of Orange Day Lily. The islands are designated as a national monument by Japan, and access to them is highly restricted.

In a paper published in the journal Phytotaxa on 9 June 2017, Takuro Ito of the United Graduate School of Agricultural Science at the Tokyo University of Agriculture and Technology, and the Department of Botany at the National Museum of Nature and Science, Hiroko Nakanishi of the Nagasaki Subtropical Botanical Institute, Yoshiro Chichibu and Kiyotaka Minoda of Nagasaki and Goro Kokubugata, also of the United Graduate School of Agricultural Science at the Tokyo University of Agriculture and Technology, and the Department of Botany at the National Museum of Nature and Science, describe a new species of Succulent Plant from the Danjo Islands.

The new species is described from a previously known population, which had been ascribed to the species Sedum formosanum, which is also known from Taiwan and the Philippines. However, the flowers are of Sedum formosanum elsewhere have five petals and ten stamens, while the Danjo Islands population have four petals and eight stamens. A study of the DNA of the Danjo population revealed them to be a distinct species, rather than just a local mutation, and this is species is described as Sedum danjoense, where ‘danjoense’ means ‘from Danjo’. 

Sedum danjoense. (A) Habitat and habit. (B) Inflorescence. (C) Adaxial surface. (D) Abaxial surface. (E) Flower. (F) Sepals. (G) Carpels. (H) Branching. Scale bars are 25 mm for (A), 5 mm for (B)–(H). Ito et al. (2017).

See also...

http://sciencythoughts.blogspot.co.uk/2017/02/impatiens-bokorensis-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2016/12/lecanorchis-tabugawaensis-new-species.html
http://sciencythoughts.blogspot.co.uk/2016/11/carex-concava-new-species-of-sedge-from.htmlhttp://sciencythoughts.blogspot.co.uk/2016/02/rafflesia-consueloae-dwarf-corpse.html
http://sciencythoughts.blogspot.co.uk/2015/06/balanophora-coralliformis-new-species.htmlhttp://sciencythoughts.blogspot.co.uk/2015/05/liparis-wenshanensis-new-species-of.html
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Magnitude 6.8 Earthquake off the south coast of Guatemala.

The United States Geological Survey Recorded a Magnitude 6.8 Earthquake at a depth of 46.8 km about 23 km to the southwest of the city of Puerto San Jose on the Pacific Coast of  Guatemala, slightly after 6.30 am local time (slightly before 12.30 pm GMT) on Thursday 22 June 2017. This event was felt across much of central and southern Guatemala and El Salvador, as well as parts of neighbouring Mexico and Honduras, though there are no reports of any casualties or major damage, though minor damage to buildings has been recorded across a wide area, as well as several small landslides.

Damage to a building i Antigua, Guatemala,following an Earthquake on 22 June 2017. Luis Escheverria/Reuters.

Guatemala is located on the southern part of the Caribbean Plate, close to its boundary with the Cocos Plate, which underlies part of the east Pacific. The Cocos Plate is being pushed northwards by expansion of the crust along the East Pacific Rise, and is subducted beneath the Caribbean Plate along the Middle American Trench, which runs parallel to the south coast of Guatemala and neighbouring countries, passing under Central America as it sinks into the Earth's interior. This is not a smooth process, the plates tend to stick together, breaking apart again once the pressure from the northward movement of the Cocos Plate builds up to much, triggering Earthquakes.

The approximate location of the 22 June 2017 Guatemalan Earthquake. USGS.

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/2017/05/warnings-issued-after-eruptions-on-mout.htmlhttp://sciencythoughts.blogspot.co.uk/2017/02/eruptive-episode-on-mount-fuego.html
http://sciencythoughts.blogspot.co.uk/2016/12/magnitude-54-earthquake-in-escuintla.htmlhttp://sciencythoughts.blogspot.co.uk/2016/08/explosive-eruptions-on-mount.html
http://sciencythoughts.blogspot.co.uk/2015/11/eruptions-on-mount-fuego-guatemala.htmlhttp://sciencythoughts.blogspot.co.uk/2015/10/hundreds-feared-dean-after-landslide-in.html
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Wednesday, 21 June 2017

Sphodromerus carapezzanus: A new species of Grasshopper from Dhofar, Oman.

The Arabian Peninsula lies between the continents of Africa and Asia, providing a bridge between the two, and the area hosts a mixture of African and Asian wildlife. The area also contains a wide range of micro-habitats, particularly where large expanses of arid desert separate isolated areas with moister climates. These isolated micro-habitats are often home to endemic species, not found anywhere else.

In a paper published in the journal ZooKeys on 8 June 2017, Bruno Massa of the Department of Agriculture at the University of Palermo describes a new species of Grasshopper from Wadi Ayun in the Dhofar Governate of Oman.

The new species is placed in the genus Sphodromerus, and given the specific name carapezzanus, in honour of Attilio Carapezza, the Italian heteropterologist (scientist that studies True Bugs, Heteroptera), who collected the specimens from which the species is described, during an expedition to the area by the Museum of Cardiff in 2016. The species is described from two specimens, one male and one female. Both are dark brown in colour with a rough surface and some lighter spots, the female being slightly larger than the male. 

Sphodromerus carapezzanus. Male (top) and female (bottom). Massa (2017).

See also...

http://sciencythoughts.blogspot.co.uk/2016/01/arulenus-miae-new-species-of-pygmy.htmlhttp://sciencythoughts.blogspot.co.uk/2015/08/eneopterine-crickets-from-leyte-island.html
http://sciencythoughts.blogspot.co.uk/2015/05/three-new-species-of-mud-crickets-from.htmlhttp://sciencythoughts.blogspot.co.uk/2015/01/two-new-species-of-katydids-from.html
http://sciencythoughts.blogspot.co.uk/2014/10/three-new-species-of-katydid-from-china.htmlhttp://sciencythoughts.blogspot.co.uk/2014/08/a-new-species-of-pygmy-grasshopper-from.html
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Monday, 19 June 2017

An Enantiornithine Bird Hatchling preserved in Cretaceous Burmese Amber.

Most Dinosaurs, including Mesozoic Birds, are known only from replacement fossils of bones, teeth, and other hard tissues, with a few rare sites such as the lithographic deposits of the Jehol or Crato biotas, or even rarer examples of Dinosaurs mummified before lithification, preserving additional details such as plumage and soft tissues. One type of deposit with potential for excellent preservation of plumage and soft tissues is amber, the preserved resin of ancient trees, which frequently preserves whole body fossils of Insects and other small animals. However Amber fragments, by their nature, tend to be very small, whereas Dinosaurs, for the most part, were extremely large, limiting the potential for the preservation of even Avian Dinosaurs in amber. To date, the known catalogue of Dinosaur specimens preserved in amber runs to a few feathers, a pair of Enantiornithine Bird wings and the tip of the tail of a small non-Avian Coelurosaurian Theropod.

In a paper published in the journal Gondwana Research on 6 June 2017, Lida Xing of the State Key Laboratory of Biogeology and Environmental Geology and School of the Earth Sciences and Resources at the China University of Geosciences, Jingmai O'Connor of the Key Laboratory of Vertebrate Evolution and Human Origins at the Institute of Vertebrate Paleontology and Paleoanthropology of the Chinese Academy of Sciences, Ryan McKellar of the Royal Saskatchewan Museum, the Biology Department at the University of Regina, and the Department of Ecology & Evolutionary Biology at the University of Kansas, Luis Chiappe of the Dinosaur Institute at the Natural History Museum of Los Angeles County, Kuowei Tseng of the Department of Exercise and Health Science at the University of Taipei, Gang Li of the Institute of High Energy Physics of the Chinese Academy of Science, and Ming Bai of the Key Laboratory of Zoological Systematics and Evolution of the Institute of Zoology of the Chinese Academy of Sciences, describe a preserved Hatchling Enantiornithine Bird from a piece of amber from the Angbamo site at Tanai Township in Myitkyina District of Kachin Province in northern Myanmar.

Middle Cretaceous ‘Burmese Amber’ has been extensively worked at several sites across northern Myanmar (though mostly in Kachin State) in the last 20 years. The amber is fairly clear, and often found in large chunks, providing an exceptional window into the Middle Cretaceous Insect fauna. This amber is thought to have started out as the resin of a Coniferous Tree, possibly a Cypress or an Araucaria, growing in a moist tropical forest. This amber has been dated to between 105 and 95 million years old, based upon pollen inclusions, and to about 98.8 million years by uranium/lead dating of ash inclusions in the amber. 

The preserved Hatchling is not intact, having apparently only partly covered by resin initially, with part of the body therefore left exposed to the actions of the elements, and scavengers, and hence lost; the whole subsequently covered by additional layers of resin, and eventually preserved as amber. The remains are preserved in a block of amber approximately 86 mm x 30 mm x 57 mm and weighing 78.16 g. This block has been split into two sections during preservation; this split having unfortunately passed through part of the jaw, causing some loss of material. The remains comprise the head and most of the neck of the Bird, as well as a partial wing and the feet, and some additional plumage and soft tissue.

Overview of specimen in right lateral view. (A) Amber specimen; (B) x-ray μCT reconstruction; (C) illustration of observable plumage and skin sections. Two halves of amber piece have been positioned side by side (A) or separated by dashed line (C), and body regions scanned separately have been arranged in preservational position (B). For clarity in (C), only rachises of apical remiges indicated; and only rachises and rami of basal remiges, coverts, contours, and neoptile plumage indicated. Scale bars represent 10 mm. Xing et al. (2017).

The Bird appears to have two basic types of plumage, soft down feathers similar to those seen in modern Bird chicks, combined with longer fibrous feathers similar to those seen in many Dinosaurs, as well as some developed flight feathers on the wing. The skeleton is consistent with that of other preserved early-development Enantiornithine chicks, lending confidence to the diagnosis of this bird as an Enantiornithine. The developmental strategy in this Bird appears to have been different to that in modern Birds, in that it was apparently both arboreal (tree-dwelling) and precocial (able to move about immediately upon hatching). Modern Birds almost invariably follow one of two strategies; with tree-nesting species tending to need a period of care before leaving the nest (though many species do leave the nest before they can fly) and ground-nesting Birds producing precocial offspring that become active almost immediately.

See also...

http://sciencythoughts.blogspot.co.uk/2016/12/preserved-plumage-in-immature.htmlhttp://sciencythoughts.blogspot.co.uk/2015/06/preserved-feathers-in-enantiornithine.html
http://sciencythoughts.blogspot.co.uk/2015/01/bird-eggs-from-late-cretaceous-colonial.htmlhttp://sciencythoughts.blogspot.co.uk/2014/07/two-new-species-on-enantiornithine.html
http://sciencythoughts.blogspot.co.uk/2014/06/a-subadult-enantiornithine-bird-from.htmlhttp://sciencythoughts.blogspot.co.uk/2014/06/preserved-ovarian-follicles-in-mesozoic.html
 
 
 
 
 
 
 
 
 
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Sunday, 18 June 2017

Understanding the integument of Tyrannosaurid Dinosaurs.

Many recent discoveries of Theropod Dinosaurs have revealed traces of feather coverings, leading to speculation that all members of this group may have been feathered. The discovery of the feathered Tyrannosaurids, Dilong paradoxus and Yutyrannus huali, from the Early Cretaceous of China, has extended this speculation to the very largest Tyrannosaurid Dinosaurs, particularly as Yutyrannus itself was a large Tyrannosaurid (about nine meters) with an extensive feather coat, raising the possibility that the largest known Therapod Dinosaur, Tyrannosaurus rex, might have had feathers.

In a paper published in the journal Biology Letters on 7 June 2017, Phill Bell of the University of New England, Nicolás Campione of the Palaeobiology Programme at Uppsala University, Scott Persons and Philip Currie of the University of Alberta, Peter Larson of the Black Hills Institute of Geological Research, Darren Tanke of the Royal Tyrrell Museum of Palaeontology and Robert Bakker of the Houston Museum of Natural Science, describe the results of a study of skin traces from Tyrannosaurus rex and several other large Tyrannosaurids, and draw conclusions about the evolution of skin covering of Tyrannosaurid Dinosaurs from this study.

Bell et al. examined a number of skin traces associated with a Tyrannosaurus specimen collected from the Hell Creek Formation near Baker in Montana (specimen HMNS 2006.1743.01, sometimes known as ‘Wyrex’). This specimen has numerous skin patches from different parts of its body, none of which show any trace of feathers, leading Bell et al. to conclude it was featherless. The scales of HMNS 2006.1743.01 are small in size and highly variable in shape, with no larger feature scales (known from other Dinosaur species) and no scales showing polarity (i.e. having a distinct anterior-posterior axis, presumably the first step in developing towards a feather-like form). Interestingly, in several places where large patches of skin are preserved, these scales show signs of being arranged into a leaf-like pattern, with scales arranged into trapezoidal or triangular clusters, separated by bands of incised interstitial skin, which follow a branching arrangement similar to the midrib and lateral veins on a plant leaf. 

Integument of Tyrannosaurus rex (HMNS 2006.1743.01). (a) Proximal caudal vertebrae 6–8 in right lateral view. Integument from the neck (b,c), the ilium (d,e) and caudal vertebrae (f–h). Green lines indicate ‘vein and midrib’ patterns. Scale in (a) is 10 cm; (b)–(e) are 5 mm and (f)–(h) are 10 mm. Bell et al. (2017).

Next Bell et al. examined preserved skin specimens from four other large, Late Cretaceous Tyrannosaurs, Daspletosaurus, Tarbosaurus, Albertosaurus, and Gorgosaurus. Unlike the Early Cretaceous Chinese specimens, none of these Late Cretaceous North American and Mongolian Tyrannosaurs show any signs of feathers. 

The distribution of feathers among Theropod Dinosaurs suggests that at least primitive feathers (i.e. hollow tubes) were present in the earliest Coelurosaurs, the group to which the Tyrannosaurs belong, with more advanced features such as rachis, barbs and barbules and eventually fully formed flight feathers appearing sequentially within Maniraptoran Theropods and eventually Birds. Some Ornithischian Dinosaurs also had primitive feathers, suggesting that either simple feathers appeared before the two groups diverged, or that they evolved separately in the two groups. No trace of feathers or feather-like structures has ever been found in any Sauropod Dinosaur. 

Like other Coelurosaurs, the earliest Tyrannosaurs appear to have had a full coat of simple, fibrous feathers, and as in other non-avian Theropods, no Tyrannosaur has been found with evidence of a partial-feather covering. Indeed, the earliest Birds, such as Archaeopteryx, appear to have been completely covered in feathers, with the scaly feet and legs of modern Birds apparently secondarily derived. This strongly suggests that the scaly skin of later Tyrannosaurs is also secondarily derived from a feathery covering. 

The earliest Tyrannosaurs were relatively small animals, with gigantism achieved twice within the group, once rapidly, in the Early Cretaceous lineage that led to Yutyrannus, and once more gradually over the course of the Cretaceous in the lineage that culminated in Daspletosaurus, Tarbosaurus, Albertosaurus, Gorgosaurus and Tyrannosaurus. This is important, as it shows that Yutyrannus is not the ancestor of the Late Cretaceous giant Tyrannosaurs, and that it therefore presumably evolved under different ecological and evolutionary pressures to these animals, and that understanding these pressures may be the key to understanding the distribution of feathers among Tyrannosaurids. 

Some earlier studies have suggested that temperatures in Early Cretaceous western Liaoning (where Dilong paradoxus and Yutyrannus huali lived) may have been significantly cooler than the North American and Mongolian environments that produced the Late Cretaceous giant Tyrannosaurs, leading these Early Cretaceous forms to need an insulating feather coat that the Late Cretaceous forms lacked. However recent palaeoenvironmental studies have not supported this, implying a similar temperature range. One difference that may be important is tree-cover, with the Liaoning deposits thought to have been laid down in a dense forest environment, while the later Cretaceous Tyrannosaurids are believed to have inhabited more open environments. This reflects the case in modern Asian Elephants and Javan Rhinoceroses, which are live in dense forest environments and are hairier than their African relatives that live on open Savanah. While all of these animals live in hot climates, and are more concerned with losing excess heat that keeping warm (always more of a problem for large animals anyway), the Asian forms, which live beneath the shade of large trees, are apparently subject to less heat-stress than the African forms. 

However the Late Cretaceous Tyrannosaurids are known to have lived alongside feathered Dinosaurs, with Albertosaurus in particular having been found alongside feathered Ornithomimids. Bell et al. suggest that the feather-loss in Tyrannosaurids compared to Maniraptorans (such as the Ornithomimids) may be related to a more active lifestyle, i.e. expending more energy and therefore generating more body-heat. Tyrannosaurs had relatively longer legs than other large Theropods, and arctometatarsalian feet (expand), which has been interpreted as being indicative of a more active lifestyle, possibly even engaging in bouts of rapid or lengthy pursuit (generally the only ways for a large predator in an open environment to catch prey, since opportunities for ambush are relatively limited). 

Finally, the Late Cretaceous Tyrannosaurs grew considerably larger than the Early Cretaceous forms, with only the smallest, Albertosaurus, at an estimated 1325–2210 kg is thought to be comparable in size to Yutyrannus, at about 1414 kg, while the other species were much larger; Tarbosaurus at 1744–2945 kg, Gorgosaurus at 2145–3577 kg, and Tyrannosaurus at 5014–8361 kg, suggesting that these species would have been subject to more heat-stress. 

See also...

http://sciencythoughts.blogspot.co.uk/2017/03/daspletosaurus-horneri-new-species-of.htmlhttp://sciencythoughts.blogspot.co.uk/2015/02/exceptionally-large-theropod-teeth-from.html
http://sciencythoughts.blogspot.co.uk/2014/03/a-dwarf-tyrannosaurid-from-late.htmlhttp://sciencythoughts.blogspot.co.uk/2012/12/dinosaur-smuggler-changes-plea-to-guilty.html
http://sciencythoughts.blogspot.co.uk/2012/10/a-tyrannosaurid-metatarsal-from-el.htmlhttp://sciencythoughts.blogspot.co.uk/2012/06/police-seize-dinosaur-from-new-york.html
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