Wednesday 28 November 2012

A new species of tree-dwelling Fighting Fish from Thailand.

Fighting Fish (Bettas) are colourful members of the Gourami Family (Osphronemidae) popular in the aquarium trade and noted for their aggressive nesting behavior. In the wild they live in rice paddies and similar environments, where the males build bubble-nests from sticky oral secretions containing air bubbles, typically anchored to some sort of plant. The females lay their eggs in these nests, which the males then defend these nests against other males and any other perceived threats (the Thai name for the  Fish, Plaklad, translates as 'Biting Fish').

In a paper published in the journal Zootaxa on 19 October 2012, Chanon Kowasupat of the Institute for Innovative Learning at Mahidol University, Bhinyo Panijpan and Pintep Ruenwongsa of the Faculty of Science at Mahidol University and Namkang Sriwattannarothai also of the Institute for Innovative Learning at Mahidol University describe a new species of Fighting Fish found nesting in Nipa Palms (Nypa fruticans) in Samut Sakhon Province, Thailand.

Nipa Palms are a form of Mangrove; trees which can tolerate immersion in salt water, and which colonize tidal flats and salt marshes, forming unique habitats. The Palms trap pools of water at the bases of their leaf stems, similar to the pools of Bromeliads, and it is in these pools that the new species of Fighting Fish nests. The population has been known of for some time by fish enthusiasts, and there has been some prior speculation as to whether they were a separate species, or a population of the more widespread Splendid Fighting Fish, Betta splendens.

(a) A Nipa Palm stand in Samut Sakhon Province, Thailand. (b) Water pockets at the base of the leaf stems of a Palm, with Fish found within one of the pockets inset. (c) The Fish inside the pocket, with a bubble-nest to the right. Kowasupat et al. (2012).

Kowasupat et al. have now confirmed this Fish is a separate species, based upon both morphology and DNA analysis. They name it Betta mahachaiensis, after Maha Chai, where the Fish were first noted and where the suspicion they might be a separate species began. It was found at a number of sites in Samut Sakhon Province, west of Bankok. These sites are not pristine natural environments, they are disturbed by human activity (Nipa Palm is used as a roofing and basket-making material as well as an animal feed, and Arrack, a form of palm-wine, is made from its sap), and all are threatened by expansion of human settlements into the salt-marshes where they occur, suggesting that Betta mahachaiensis, is under threat from human activity. The area has also recently become prone to flooding with fresh-water, something which both the Palms and the Fish can tolerate, but which brings larger predators into the marshes.

(a) Map of Thailand showing the area where Betta mahachaiensis was found (rectangle). (b) Expanded map of the inset area, showing sites where Betta mahachaiensis and the related Betta splendens were found. Kowasupat et al. (2012).

Betta mahachaiensis is a 120-140 mm Fighting Fish, black or brown with iridescent green or bluish-green scales. The males are considerably more conspicuous than the females. 

Betta mahachaiensis; (top) male & (bottom) female. Kowasupat et al. (2012).

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Tuesday 27 November 2012

Soft tissue preservation in Linguloid Brachiopods from the Early Ordovician Fenxiang Formation of Hubei Province, China.

Brachiopods (or Lampshells) superficially resemble Bivalve Molluscs, though they are not closely related. They have a filter feeding apparatus called a lophophore, unlike anything found in any Mollusc, but also found in Bryozoans and Phoronid Worms. This is encased with in a shell with two valves, each symmetrical about a midline, but not necessarily the same as each other, along with the rest of the organs of the body; there is typically remarkably little flesh to a Brachiopod compared to a Mollusc with a shell the same size. However one group of Brachiopods, the Linguloids, which have a long, fleshy, worm-like body with a shell enclosing only the head-area; these Brachiopods have been compared to a Phoronid Worm with a partial shell, and are considered to be the earliest group of Brachiopods; they appear in the fossil record early in the Cambrian, and essentially unchanged forms still exist today.

Modern Linguloid Brachiopods. Suny Cortland.

In a paper published in the journal Acta Palaeontologica Polonica on 1 October 2012, Andrzej Baliński of the Instytut Paleobiologii at the Polish Academy of Sciences and Yuanlin Sun of the Key Laboratory of Orogenic Belts and Crustal Evolution at the School of Earth and Space Sciences at Peking University describe the occurrence of Linguloid Brachiopods with preserved soft-tissue tails from the early Ordovician Fenxiang Formation of Hubei Province, China.

This is not the oldest such occurrence, Linguloid Brachiopods have been found with their tails preserved in both the Burgess Shale and Chengjang Faunas from the Cambrian, but it is still a significant find. The Cambrian specimens are not universally accepted as having been burrowing animals; some scientists believe that in the rather different ecosystems of the Early Cambrian they may not have needed to burrow; there is certainly no clear evidence of burrowing by any form of animal from sediments of this time. The Ordovician is a different matter, burrowing lifestyles had definitely evolved by this time, and there was no shortage of predators available to attack an exposed Linguloid Brachiopod on the surface.

The method of preservation is also different to that seen in the Cambrian fossils, which are preserved as two-dimensional aluminosilicate or degraded organic carbon films in shales (laminated mudstones), a method of preservation extremely rare after the Early Cambrian due to bioturbation of marine sediments by burrowing animals. In contrast these Ordovician fossils are preserved as three-dimensional mineralized body-fossils. In these specimens the mineralized soft tissue is a bright-red colour, due to the oxidation of iron minerals. The soft tissues are thought to have initially been replaced with hydrogen sulphide (H₂S) by sulphur-reducing bacteria in an anaerobic (oxygen-lacking environment), this Hydrogen Sulphide is then thought to have reacted with iron from the surrounding sediments, giving it its distinctive colour.

Preserved Linguloid Brachiopod from the lower Ordovician Fenxiang Formation. Scale bar is 5 mm. Baliński & Sun (2012).

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Saturday 24 November 2012

Two new species of Mosquito from the Eocene of Montana.

Mosquitoes are small Flies notorious for their habit of sucking blood. Only the females do this, the males tend to feed on pollen, nectar or plant sap. The larvae of Mosquitoes are aquatic carnivores, the adults emerging from the water to mate, lay eggs and die. This is clearly a successful lifestyle; Mosquitoes are found on every continent except Antarctica and have a fossil record dating back to the Middle Cretaceous, about 100 million years ago. 

In a paper published in the journal Zootaxa on 30 October 2012, Ralph Harbach of the Department of Life Sciences at the Natural History Museum in London and Dale Greenwalt of the Paleobiology Department at the National Museum of Natural History in Washington DC describe two new species of Mosquito from the early Eocene Kishenehn Formation of northern Montana.

Both new species are placed in the genus Culiseta, modern members of which tend to be restricted to cooler climates, but though modern Montana is rather cold, in the early Eocene it is thought to have been subtropical, with temperatures on average 15° higher than today. 

The first new species described is Culiseta kishenehn, which takes its name from the Kishenehn Formation, which in turn gets its name from the Kishenehn Creek. The name Kishenehn means 'no good' in the Kutenai language, but why it was applied to the creek is unclear. The species is named from eight adult specimens, of both sexes, the juveniles, eggs and pupae being unknown. Culiseta kishenehn was a 3 mm+ dark coloured Mosquito.

Culiseta kishenehn (top) male and (bottom) female. Harbach & Greenwalt (2012).

The second new species described is Culiseta lemniscatalemniscata meaning 'adorned with ribbons' in  Latin, the Insects having stripes on its abdomen which resemble ribbons. The species is named from two specimens, both adult females. 

Culiseta lemniscata, two female specimens. Arrows indicate position of lighter bands on the abdomen. Harbach & Greenwalt (2012).

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Citizen scientists discover a sub-Jovian planet in a quaternary star system.

The Planet Hunters is a citizen science project (i.e. a science project carried out largely by members of the public) which asks visitors to a website to look at randomly selected 30 light-curves from the Kepler Space Telescope, and look for patterns. Volunteers who find patterns that may indicate planets can flag these up for investigation by astronomers.

In a paper published on the online arXiv database at Cornell University Library on 12 October 2012, a team of scientists led by Megan Schwamb of the Yale Center for Astronomy and Astrophysics and the Department of Physics at Yale University describe the first planet discovered by the Planet Hunters project, a sub-Jovian planet in the KIC 4862625 star system (Kepler Input Catalogue 4862625), roughly 5000 light years from Earth in the constellation of Cygnus.

The planet, named PH1, has a maximum possible mass 169 times that of the Earth, slightly over half the mass of Jupiter but considerably larger than Saturn. It orbits a binary pair of stars, named Aa and Ab, every 138 days at a distance of 0.634 AU (63.4% of the distance at which the Earth orbits the Sun). The larger of these two stars Aa, is an F-type yellow-white star, with a mass of 1.5 times the mass of the Sun. This is orbited by a smaller, M-type red dwarf star with a mass 0.4 times that of the Sun every 20 days at a distance of 0.17 AU. All of these components eclipse (pass in front of) one-another when seen from our Solar System.

Diagram showing the relative positions of PH1, Aa and Ab in the inner part of the KIC 4862625 system. Shwamb et al. (2012).

Orbiting this system at a distance of roughly 1000 AU is a second pair of binary stars, detected by their gravitational influence upon the primary binary. These are named Ba and Bb, Ba probably being a G-type yellow dwarf star with 99% of the mass of our Sun and Bb probably being a M-type red dwarf star with a mass 51% if the Sun's.

The whole system is thought to be about 2 billion years old, compared to about 4.5 billion years for our Solar System.

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Friday 23 November 2012

A new species of Slipper Limpet from Chile.

Slipper Limpets, Calyptriaeidae, are new world Gastropods more closely related to Conches and Cowries than to true Limpets; they are so named because their shells tend to be broad, flat and relatively unwhorled (though not conical as in a true Limpet). The inside of the shell contains a half-shelf, which resembles a slipper or shoe to some people, hence the slipper part of the name. The living snails have a tendency to form chains of animals, with up to 25 individuals perched on top of one another. In such chains only the bottom animal will be female, all the others male. When the female dies, the next male in the chain changes sex and becomes a female (all the animals develop as males initially).

In a paper published in the journal Molluscan Research on 28 September 2012, David Veliz of the Departamento de Ciencias Ecológicas and Instituto de Ecología y Biodiversidad at the Universidad de Chile, Federico Winkler of the Departamento de Biología Marina at the Universidad Católica del Norte, Chita Guisado of the Facultad de Ciencias del Mar y Recursos Naturales at the Universidad de Valparaíso and Rachel Collin of the Smithsonian Tropical Research Institute describe a new species of Slipper Limpet from the intertidal zones of northern Chile.

The new species is placed in the genus Crepipatella, and given the specific name occulta, referring to the fact that it is a cryptic species, previously hidden within documented populations of other species. Crepipatella occulta resembles both other species of Crepipatella found in the region, Crepipatella dilatata and Crepipatella peruviana, but differs from them in its development. 

Crepipatella peruviana has a planktic larval stage, whereas Crepipatella dilatata lays its eggs in capsules with non-developing 'nurse-eggs', upon which the young Snails feed before emerging as miniature adults. Crepipatella occulta also produces an egg capsule, but one which lacks nurse-eggs, rather the young snails feed on less fast-developing embryos (so called 'nurse-embryos') before emerging, in a manner similar to the interuterine cannibalism seen in some Sharks, Teleost Fish and Salamanders.

Crepipatella occulta; (top) juvenile, the arrow indicates the point at which the Snail left the egg capsule, (bottom) growth series. Veliz et al. (2012).

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The stomach contents of two Early Cretaceous Compsognathid Dinosaurs.

Assessing the diet of extinct animals is problematic; a broad estimate can be made from the animals dentition, which can indicate that an animal ate meat (bladed teeth), plant material (grinding teeth), fish (pointed teeth) or shellfish (crushing teeth); but beyond this it is very hard to guess the eating habits of long dead animals. One thing that can indicate clearly what an ancient animal was eating is to find preserved specimens with intact stomach contents, although such specimens are rather rare, and found only in deposits with exceptional preservation.

In a paper published in the journal PLoS One on 29 August 2012, a team of scientists led by Lida Xing of the Department of Biological Sciences at the University of Alberta describe two specimens of the large Compsognathid Dinosaur, Sinocalliopteryx gigas, from the Jianshangou Beds of the lower Yixian Formation (part of the Jehol Biota lagerstatte), from Liaoning Province, China, both of which have intact stomach contents.

The first specimen is a more-or-less complete skeleton, with a mass of what appear to be feathers and the hind foot and lower limb of a small Dromaeosaurid Dinosaur, possibly Sinornithosaurus. These contents are arranged in a rough 'C' shape, suggesting this may be the contour of the gut.

Sinocalliopteryx gigas, complete specimen with stomach contents. Xing et al. (2012).

(Top) Magnification of the abdominal area of the intact specimen of Sinocalliopteryx gigas. (Bottom) Interpretive drawing of the above. Blue, undigested feather-like structures; Red, dromaeosaurid hindlimb; Yellow, gastroliths. Abbreviations: Dr, dorsal rib; F, femur; H, humerus; Pu, pubis. Xing et al. (2012).

The second specimen is more fragmentary, but also has well preserved intact stomach contents, suggesting that the fragmentation occurred after the specimen had been lithified. This appears to show the partial remains of two Birds, probably belonging to the species Confuciusornis sanctus. These are reasonable intact, and show the same level of acid etching from the stomach's digestive juices, suggesting that they were consumed more-or-less whole and in rapid succession. 

Stomach contents of the disarticulated specimen of Sinocalliopteryx gigas. (A,B) Photograph of block containing Confuciusornis (blue) and unidentified Ornithischian (red) remains. (C) Close up of Confuciusornis sternal and pectoral elements (small box in B). (D,E) Associated skeleton of Confuciusornis (large box in B). (F) Proximal Confuciusornis humerus.
Xing et al. (2012).

A terrestrial predator feeding on Birds at fist seems surprising, but this is behaviour known in a number of modern predators, including various members of the Cat family, as well as Foxes, some Snakes and Monitor Lizards. Such behaviour is usually indicative of a stealth predator, able to get within striking distance of its prey before it is detected.

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Thursday 22 November 2012

A Eutherian Mammal from the Late Cretaceous of Kazakhstan.

Biologists studying modern mammals divide them into three groups, the egg-laying Monotremes, the pouched Marsupials, and the large-baby-producing Placentals. For palaeontologists the situation is not so clear, since it is usually impossible to tell how a fossil specimen reproduced. Palaeontologists consider all Mammals that fit within modern Placental groups, or which seem to have shared a common ancestor with them more recently than the common ancestor of all Placental groups, to be Placental Mammals, but have a wider term, the Eutheria, to describe the Placentals plus all Mammals more closely related to modern Placental Mammals than to the Marsupials. The Eutheria first appear in the fossil record in the Late Jurassic, 160 million years ago, and by the end of the Cretaceous appear to have become the dominant group of Mammals across modern Eurasia and North America. However for much of the Mesozoic they were overshadowed by the Multituberculates, an extinct group of Mammals more closely related to the Therians (Marsupials + Eutherians) than to the Monotremes. Exactly when the Eutherians took over as the dominant group is unclear, since Mammal fossils are fairly rare from the Mesozoic (this does not imply that Mammals were rare, simply that they were not following lifestyles likely to get them into the fossil record), and assemblages of fossil Mammals even more so.

In a paper published in the journal Acta Palaeontologica Polonica on 23 October 2012, Alexander Averianov of the Zoological Institute of the Russian Academy of Sciences, David Archibald of the Department of Biology at San Diego State University and Gareth Dyke of Ocean and Earth Sciences, National Oceanography Centre at the University of Southampton, describe a new Eutherian Mammal from the Late Cretaceous Bostobe Formation, exposed at the locality of Shakh Shakh in the northeast of the Aral Sea Region of Kazakhstan.

Map showing the location of the Shakh Shakh site in Kazakhstan. Averianov et al. (2012).

The new specimen is named Zhalmouzia bazhanoviZhalmouzia after the Zhalmouz Well, a nearby landmark, and bazhanovi after Valerian Semenovich Bazhanov, a Russian palaeontologist who worked on material from the region in the 1970s. The specimen is a fraction of a dentary (lower jaw) 15 mm in length, bearing two intact teeth.

The lower jaw of Zhalmouzia bazhanovi. Averianov et al. (2012).

See also A Eutherian Mammal from the Jurassic of China and Mammals on Sciency Thoughts YouTube.

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Wednesday 21 November 2012

Miocene Quasimodo Flies in Dominican Amber.

Quasimodo Flies (Curtonotidae) are small Flies with dull colouration and distinctively humped backs. They are distributed throughout the world, though in most places they are quite uncommon. However in Africa and tropical America they are an abundant and diverse part of the insect fauna. The group have not been extensively studied, and therefore are not well understood.

In a paper published in the American Museum Novitates on 18 October 2012, David Grimaldi Division of Invertebrate Zoology at the American Museum of Natural History and Ashley Kirk-Spriggs of the National Museum in Bloomfontein and the School of Life Sciences at the University of KwaZulu-Natal describe two new species of Quasimodofly from Miocene amber from the Dominican Republic, thought to be 15-20 million years old. Only one fossil Quasimodofly has previously been described (Curtonotum gigas from French Oligocene shale in 1937), and this is now thought to have been erroneously placed, making these new specimens both the oldest and the only known fossils of the group.

The first new species is placed in the pre-existing genus Curtonotum (an extant genus of Quasimodo Flies to which Curtonotum gigas was assigned; the species was removed from the genus and family in 2007 in a paper by Ashley Kirk-Spriggs, but has never been reassigned to another taxon), and given the specific name electrodominicum, meaning from Dominican amber (ēlectron, Greek for amber, plus dominicum, from Dominica). Curtonotum electrodominicum is 7 mm Fly, not significantly humpbacked, named from a single specimen in amber. 

Curtonotum electrodominicum, specimen in amber. Grimaldi & Kirk-Spriggs (2012).

The second new species is placed in a new genus, Depressonotum, meaning flattened, and given the specific name priscum, meaning ancient. The species is named from two specimens, one male and one female, with an average length of 2.77 mm, large eyes and a flattened abdomen. The male is notably more slender than the female.

Depressonotum priscum; (top) female, (bottom) male. Grimaldi & Kirk-Spriggs (2012).

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Tuesday 20 November 2012

Eruption on Mount Paluweh.

Paluweh (or Rokatenda) is an island volcano 10 km off the north coast of Flores Island. It rises 875 m above sea level, or roughly 3000 m above the sea floor, forming a flattened conical island 8 km wide. The volcano is fairly active, having erupted seven times in the twentieth century, although it is likely that other eruptions occurred and were missed, due to the remote nature of the island. The largest recorded eruption occurred in 1928, when an explosive eruption caused a massive landslide, triggering a tsunami that killed 160-300 people.

Paluweh Island. Mangiwau/Flikr.

On 11 to 13 November 2012, the Darwin Volcanic Ash Advisory Centre reported a plume rising 2.4 km above the island which drifted 90-150 km to the northwest. According to the Jakarta Post 196 people have left the island, out of a population of roughly 6000, and 109 of these have needed hospital treatment for respiratory conditions.

Ash column apparently rising from a side vent on Paluweh. Noticieros Televisa.

Flores (and Paluweh) sits on the northern part of the Timor Microplate; a small fragment of crust caught between the Banda Sea Plate to the north and the Australian plate to the south. Both these other plates are subducting beneath the Timor Plate, and as they sink into the Earth, melted by the friction and the heat of the planets interior. Some of this melted material then rises through the overlying plate, fueling the volcanoes of Flores and Timor.

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Sunday 18 November 2012

Two feared dead after explosion on oil rig in Gulf of Mexico.

Two workers are feared dead after an explosion on an oil rig in the Gulf of Mexico on Friday 16 November 2012. The men, described as Philippine nationals, reportedly jumped from the rig following an explosion during maintenance work. There is not thought to be any danger of a major oil spill, as the rig was not in operation at the time of the explosion. 

Image of the oil platform burning in the Gulf of Mexico on Friday. Reuters/KLFY TV10.

The rig's owners, Black Elk Energy, have issued a statement to the effect that the explosion was caused when a worker mistakenly attempted to cut through a pipe containing oil with a welding torch. The company has also emphasized that none of their own employees were on the rig at the time of the incident, the work was being carried out by contractors from Grand Isle Shipyard Inc. Eleven workers were airlifted from the rig by the US Coast Guard following the incident.

A body has reportedly been found near the platform by divers, and is thought to be one of the missing men. Four other workers remain in hospital in Lousiana, two of whom are described as being in a critical condition. These men are also Philippines nationals.

Some oils has been seen on the water near the rig, but this is thought to be residual oil in the pipe which was cut, an amount comparable to that found in the fuel tank of a large car, there is no reason to expect an on-going crisis, as with the 2010 BP spill in the Mexican Gulf, since the rig has not been in operation since August. Parallels between the two incidents have been made widely, unsurprising since the event comes a day after BP were ordered to pay US$4.5 billion in fines and damages relating to the incident, but the two rigs are not particularly similar; the BP rig was a deep-sea drilling operation, standing in 1500 m of water, 250 km from the coast, whereas the Black Elk rig is in shallow water, with a depth of 17 m, 32 km offshore, making for a rather different set of engineering constraints. 

An investigation will now be carried out by the US Bureau of Safety and Environmental Enforcement.

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Nine new species of tree-dwelling Tarantulas from Brazil.

Tarantulas belonging to the Subfamily Aviculariinae are tree-dwelling Tarantulas from Central and South America and the islands of the Caribbean. They are popular in the pet trade due to their docile natures; they are generally traded as 'Pinktoes' or Pink-toed Tarantulas'. Like most New World Tarantulas they seldom bite defensively, instead defending themselves with a dense covering of irritating 'urticating hairs' on their abdomens, which can be loosed by brushing with the hind legs and wafted at potential predators, causing irritation to the eyes and nose.

In a paper published in the journal ZooKeys on 23 October 2012, Rogério Bertani of the Laboratório Especial de Ecologia e Evolução at the Instituto Butantan presents a review of the Avicularinid Tarantulas of Brazil, in which he describes nine new species of Spider.

Four of the new species are placed in the genus Typhochlaena, tree-dwelling Tarantulas known only from Brazil, that nest under the bark of trees. Most species of Typhochlaena are found only in rain-forests.

The first of these new species is Typhochlaena curumimcurumim being a Tupi word meaning 'child'; the species is described from three specimens found high in a tree by local children, during an arachnological expedition to the Mata do Pau-Ferro reserve near Areia in Paraíba State in September 1999. Typhochlaena curumim is a metallic yellowish-green Tarantula with brown legs and five lateral black stripes on each side. All three specimens discovered were female.

Typhochlaena curumim. Bertani (2012).

The second species described is Typhochlaena paschoali, named in honour of Elbano Paschoal de
Figueiredo Moraes, a Brazilian environmentalist, and founder of the Grupo Ambientalista da Bahia, who died in 2011. Typhochlaena paschoali is a black Spider with brown legs and a white zigzagged patted along the central line, found at a number of locations in Bahia State.

Typhochlaena paschoali, preserved specimen (not original colours). Bertani (2012).

The third species described is Typhochlaena amma, named for the Aracnídeos e Miriápodes da Mata Atlântica project, scientists from which collected the specimens used to describe the species. The females of this species are black with a blue metallic sheen and a pink central stripe with a zigzagged border, the males are brown and black with a pale dorsal stripe, again zigzagged. The Spiders were found in the mountains of Espirito Santo State.

Typhochlaena amma, adult female. Bertani (2012).

The fourth new species described is Typhochlaena costae, in honour of Miriam Costa, formerly of the Instituto Butantan, who collected the first specimen of this species. Both the males and females are brown and black with two rows of red spots on their abdomens. In total three specimens of the species have been discovered, though its exact habitat is a mystery; one specimen having been found during a animal rescue project during a flood, a second falling into a pit trap, and the third being found inside a container of fossils.

Typhochlaena costaeadult female. Bertani (2012).

The fifth species described is placed within the genus Pachistopelma, Bromeliad-dwelling Tarantulas known only from the northeast of Brazil, and given the specific name bromelicola, meaning Bromeliad-dweller. This is only the second species ever described in the genus. It is a black or dark brown Spider with brown or golden hairs, the male has an orange abdomen.

Pachistopelma bromelicola. (Top) female, (Bottom) male. Scale bars are 10 mm. Bertani (2012).

The final four new species are placed within the genus Iridopelma, Tarantulas with distinctive tibial spurs on their legs, that nest in leaves bound together with silk threads or Bromeliads.

Tibial spurs on the legs of Tarantulas of the genus Iridopelma. Scale bars are 1 mm. Bertani (2012).

The first species of this genus described is Iridopelma vanini, named in honour of Sérgio Antonio Vanin, a Brazilian entomologist and arachnologist. This is a predominantly black Tarantula, but covered in coloured hairs that give it a brownish appearance. The spider was found in Piaui, Maranhão, Tocantins and Pará States in the north of Brazil. The environment favored by the Spider is unclear; one was found nesting under a fallen tree in a (human) disturbed area, the others in coastal sand dunes and cerrado (savanah) vegetation.

Iridopelma vanini, adult female. Bertani (2012).

The second new species in the genus Iridopelma is named Iridopelma katiae, is named after Rogério Bertani's wife, Kátia de Mendonça Faria, an illustrator who has provided work for papers on Spider taxonomy. It is a mostly black Tarantula with a reddish pattern on the dorsal part of the abdomen, found under rocks and in Bromeliads in Bahia State.

Iridopelma katiae; (top) female, (middle) male, (bottom) spiderlings in a nest in a Bromeliad. Bertani (2012).

The third new species in the genus in named Iridopelma oliveirai, named in honor of Judge João Carlos Sá Moreira de Oliveira, who allowed Rogério Bertani to gain access to Tarantulas in the Instituto Butantan collections. It is a dark grey Tarantula with reddish hairs, particularly on the abdomen. The Spiders were found in dryland vegetation; one was in a Bromeliad.

Iridopelma oliveirai; (top) female, (bottom) male. Bertani (2012).

The final new Tarantula named is Iridopelma marcoi, named after Marco Antonio de Freitas, a Brazilian zoologist and geographer who collected a number of specimens used in this study, including the only member of this species discovered. The species is named from a single specimen, an adult female Spiner, black and brown in colour with metallic blue hairs and distinctive bands on its knees. The Spider was found nesting under bark in cerrado (savanna) vegetation, one meter above the ground, at São Desidério in Bahia State.

Iridopelma marcoi, adult female. Bertani (2012).

See also Nine new species of cave-dwelling huntsman spider from LaosNew species of Cave Spider from OregonTwo new species of Pseudoscorpion from ChinaA new species of Scorpion from Western Australia and An Eocene False Scorpion from Baltic amber.

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Saturday 17 November 2012

How Bar-headed Geese cross the Himalayas.

Bar-headed Geese, Anser indicus, are well known for their annual migration between breeding grounds in Tibet, Mongolia and northern China, and wintering grounds in southern India, a migration route that involves crossing the highest part of the Himalayas. There have been frequent reports of climbers witnessing the Geese at extremely high altitudes, and they are regularly cited in popular literature as achieving sustained flights at altitudes exceeding 8000 m. However empirical data on such flights has been lacking, and migration routes in excess of 8000 m seem highly unlikely to biologists, as the air at this height is rarified (thin), providing little lift to the Geese (which are quite large Birds), and therefore requiring more energy, and at the same time depleted in oxygen, making less energy available. In favor of the high altitude migration route, it has been agued that it would represent a much shorter total journey and that it would reduce the risk of Geese flying into mountains.

Bar-headed Geese (Anser indicus) in flight. Rajiv Lather/Birding in India.

In a paper published in the Proceedings of the Royal Society Series B: Biological Sciences on 31 October 2012, a team of Scientists led by Lucy Hawkes of the School of Biological Sciences at the University of Bangor and the Environment and Sustainability Institute at the University of Exeter, present the results of a study in which Bar-headed Geese were radio-tagged in order to trace their travel routes through or over the Himalayas.

Hawkes et al. found that the Geese spent 95% of their time bellow 5784 m (still impressively high), choosing to take a longer route through the Himalayas in order to utilize lower-altitude valleys and passes. Only 10 of the 91 Geese tagged were ever recorded above this altitude, and only one exceeded 6500 m, reaching 6540 m on an overnight flight, when the air was particularly cool (and therefore dense). While they cannot rule out the possibility that Geese do sometimes reach higher altitudes, Hawkes et al. strongly suspect that tales of Geese flying at 8000 m are apocryphal, owing more to climbers' folk-law than to accurate observation.

(a) Map showing the migration routes of the tagged birds. (b) The land elevation of a cross-section through the migration route (exaggerated). Hawkes et al. (2012).

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Friday 16 November 2012

How Cow pats help the spread of the Invasive Cane Toad in northern Australia.

The Cane Toad, Rhinella marina, is a large, toxic, Amphibian from Central and South America, introduced to 1935 as a biological control of the Cane Beetle, Dermolepida albohirtum, an agricultural pest. Unfortunately the Toad proved to be rather poor at controlling the Beetles, and very good at consuming a variety of Australian invertebrates, as well as poisoning local predators, which evolved in an environment free of poisonous potential prey items and have been slow adapting to the introduction. Since their introduction the Toads have spread across much of northeast Australia, and caused a great deal of problems for local conservation efforts.

A Cane Toad, Rhinella marina. Burrum River & Howard Community Website/Eva Ford.

The spread of the Toads is particularly associated with agricultural land, particularly cattle ranching, which provides year-round irrigation and extended strips of Toad-friendly environment along which to spread. In a paper published in the journal PLoS One on 7 November 2012, Edna González-Bernal, Matthew Greenlees, Gregory Brown and Richard Shine of the School of Biological Sciences at the University of Sydney, discus the results of an investigation into anecdotal evidence that the spread of the Toads is somehow facilitated by the presence of Cow pats (excrement) in the environment.

González-Bernal et al. investigated whether the Toads really did associate with Cow pats, as they were rumored to do, and also whether the Cow pats helped them to retain moisture, to regulate their temperature or to gain access to food. 

They found that Toads in an environment with Cow pats would be found on or near to the pats more than would be expected by random chance, but that the Cow pats, despite being warm and wet, made no difference to the body temperature of Toads upon them, and were, if anything, slightly more likely to absorb moisture from the Toads than the other way around. 

However the Cow pats did appear to contribute to the Toads feeding strategy, with Toads near to pats able to consume Dung Beetles, another introduced species, which apparently make up a considerable proportion of the Toads diet on land used for pasture. This suggests that the presence of cattle farms does indeed facilitate the spread of the Toads.

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Eruption on Volcán El Reventador.

Volcán El Reventador is a 3562 m volcano rising out of the jungle of the western Amazon Basin, and considered to be one of the most active volcanoes of the Ecuadorean Cordillera Real. The volcano comprises a on older, forested, 4 km wide caldera, open to the east, with a younger, unforested, active stratovolcano (cone shaped volcano) within, rising 1300 m above the caldera floor. The recorded history of Volcán El Reventador goes back to April 1541, with at least 25 major eruptions in this time, though it is quite likely that some will have been missed, due to the remote location of the volcano. The largest recorded eruption on Volcán El Reventador occurred in 2008, when an ash-column rose 6 km into the air and was accompanied by explosions, pyroclastic flows, lava flows and lahars.

A steam plume rising above Volcán El Reventador in February 2012. Endless River Adventures.

Volcán El Reventador has produced columns of ash and steam for much of 2012, but has otherwise been inactive. On 3-4 November an ash plume rose 3 km above the summit, and on 9 November, following a visit to the site by volcanologists, the Instituto Geofísico-Escuela Politécnica Nacional reported a new phase of activity had started on the mountain, with lava flows on the north and south flanks of the volcano, up to 2 km in length, and a lava dome (mound-shaped protrusion resulting from the slow extrusion of viscous lava) rising above the crater walls. On 13 November the Washington Volcanic Ash Advisory Center reported an ash column from Volcán El Reventador rising 5.2 km and drifting to the southeast.

The volcanoes of the Cordillera Real, and of South America in general, are fueled by the subduction of the Nazca Plate beneath the South American Plate. The Nazca Plate underlies a large chunk of the eastern Pacific Ocean, and is being subducted along Peru-Chile Trench to the west of South America. As it sinks into the Earth, the Nazca Plate passes under South America, where it is heated by friction with the overlying South American Plate and by the heat of the planet's interior. This causes the Nazca Plate to partially melt, and some of this melted material then rises through the South American Plate as magma, fueling the volcanoes of the Andes. The motion of one plate beneath another is not a smooth process, and the Nazca and South American Plates frequently stick together, then break apart as the pressure builds up, triggering frequent Earthquakes along the western coast of South America, and sometimes further inland.

The subduction of the Nazca Plate beneath the South American Plate, and how it causes Earthquakes and volcanoes. SIO SEARCH.

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Thursday 15 November 2012

Symbiotic Bacteria in Snails on the Eastern Lau Spreading Center.

Hydrothermal vents in the deep oceans are colonized by a broad array of invertebrates that have symbiotic relationships with chemotropic Bacteria. These Bacteria are able to derive energy from chemicals discharged by the vents, providing a base for ecosystems entirely separated from the light of the Sun. Not all hydrothermal vent systems are the same; a volcanic field will typically contain a variety of hydrothermal vent systems with different chemical properties, which would imply that different Bacteria would be needed to metabolize the chemicals produced. Ordinarily we would expect different symbionts to have different hosts, but hydrothermal vents tend to have similar faunas to the vents closest to them physically, not those with the most similar chemistry, suggesting that in this instance the hosts are able to form symbiotic relationships with a variety of different Bacteria.

In a paper published in the Proceedings of the National Academy of Sciences, a team of scientists led by Roxanne Beinart of the Department of Organismic and Evolutionary Biology at Harvard University discuss the results of a study into Snails of the genus Alviniconcha at a number of chemically different sites on the Eastern Lau Spreading Center, a divergent plate margin that connects North Island, New Zealand to the islands of Tonga.

Map of the northern  Eastern Lau Spreading Center, showing the four sites from which Snails were sampled. Beinart et al. (2012).

Alviniconcha Snails are widely distributed at hydrothermal vents in the eastern Pacific and Indian Ocean. Beinart et al. sampled them at four sites on the Eastern Lau Spreading Center. The northernmost two of these, Tow Cam and Kilo Moana, are dominated by basaltic lavas, and the southern two, ABE and Tu’i Malila, by andesitic lavas. 

A single Alviniconcha Snail. Beinart et al. (2012).

A colony of Alviniconcha Snails at a vent on the Eastern Lau Spreading Center. Beinart et al. (2012).

Beinart et al. found that each of the Snails was contained Bacteria predominantly from one of three groups. Snails from the two northern, balsaltic, vents were dominated by ε-proteobacteria, while those at the southern two sites by one of two forms of γ-proteobacteria, named the γ-1 and γ-Lau strains.

This suggests that the Snails, and potentially other organisms living in similar ecological niches at hydrothermal vents, are capable of forming symbiotic relationships with different types of bacteria to fit the local environment. This would be a big help to the Snails in colonizing new vent-sites, as it means that planktic larval Snails would be capable of colonizing any vent they encountered, not just ones with suitable chemistry for a specific Bacterial symbiont.

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