World’s largest canary studied


This 17 March 2015 video says about itself:

Inaccessible Island bunting (or Inaccessible Island finch) (Nesospiza acunhae) on Inaccessible Island in the Tristan da Cunha archipelago, south Atlantic Ocean.

The Inaccessible Island bunting was thought to be closely related to the São Tomé grosbeak, more to the north in the Atlantic. However, recent research says it is not.

From Lund University in Sweden:

The world’s largest canary

June 21, 2017

Biologists at Lund University, together with their colleagues from Portugal and the UK, have now proven that the endangered São Tomé grosbeak is the world’s largest canary — 50 per cent larger than the runner-up.

The São Tomé grosbeak is one of the rarest birds in the world and can only be found on the island of São Tomé in the West African Gulf of Guinea. After the bird was discovered in 1888, another 101 years went by before it was spotted again by birdwatchers.

Until now, it has been categorised as Nesospiza — “the new finch” —

No, ‘island finch’. ‘New finch’ would be Neospiza.

but new DNA analyses, performed by the researchers, show that it is a canary or seedeater of the genus Crithagra.

The São Tomé grosbeak is distinguished by its size (20 cm long), flat head and very large beak.

The island nation of São Tomé and Príncipe has never been attached to the mainland. Its 1,000 square kilometres contain a total of 28 endemic bird species. This can be compared to the 22 endemic species found on the Galápagos, which is 100 times larger.

Because the small islands have been isolated for so long, several species have evolved rapidly and distinguished themselves from their relatives on the mainland — a phenomenon known as the “island effect.” The seclusion of an island involves an evolution by which some species develop so-called gigantism — they become giants. The opposite evolutionary process — that animals become smaller — is also common.

São Tomé and Príncipe have been inhabited for more than 500 years, but have remained fairly intact. In fact, there is still no documented extinction of a species on these islands, although presently some species are critically endangered.

Cormorants can hear under water, new research


This video says about itself:

HUMAN NOISE DISTURBING MARINE BIRDS

29 May 2017

For the first time a study shows that cormorants can hear under water. This means they can hear – and be disturbed by – human noise: ships, construction work, etc.

From the Rare Bird Alert site:

New discovery: Cormorants can hear under water

20 June 2017

For the first time, researchers have shown that marine birds can hear under water. This offers new possibilities for the protection of marine birds in trafficked waters. Seals, whales and other marine animals can hear under water. The cormorant also has this ability, which new research from University of Southern Denmark (SDU) shows.

According to the biologists it makes good sense that a cormorant can hear under water — the environment where it finds most of its food.

About every tenth bird species — ca. 800 species — in the world hunts under water, and it may turn out that they too can also hear under water.

The sound of fish

Researchers Kirstin Anderson Hansen, Alyssa Maxwell, Ursula Siebert, Ole Næsbye Larsen and Magnus Wahlberg from the Department of Biology at University of Southern Denmark have tested the cormorant Loke’s hearing. Loke lives at SDU’s marine biology research station in the Danish town Kerteminde.

“Hearing under water must be a very useful sense for cormorants. They depend on being able to find food, even if the water is not clear, or if they live in the Arctic regions where it is dark for long periods at a time,” says Kirstin Hansen, Ph.D.

Loke’s hearing abilities are on a par with the hearing of the toothed whale and the seal.

The sound of humans

He can hear sounds ranging between 1 and 4 kHz, and it is in this range that fish such as sculpin and herring produce sounds. Both sculpin and herring are on the cormorant’s menu.

1 — 4 kHz is not only the range in which fish sounds are found. There are also various human-made sounds found in this range.

Human-made sounds can disturb the ocean’s animals to such an extent that they cannot find food or communicate with each other. It is a known problem for porpoises and seals for instance, and now it is also a potential problem for birds. It is certainly something that we should be more aware of, says Magnus Wahlberg, Associate Professor.

Human-made sounds can be everything from spinning wind turbines and ship traffic to water scooters and drilling platforms.

The SDU biologists are now planning more trials, and the next birds to be tested will probably be guillemots and puffins.

Drowned wildebeest help other Kenyan animals


This video says about itself:

AMAZING FOOTAGE OF WILDEBEEST CROSSING THE MARA RIVER

28 January 2011

They had wanted to cross all day, and by 5-o-clock PM they finally did.

From the Cary Institute of Ecosystem Studies in the USA:

Wildebeest feast: Mass drownings fuel the Mara River ecosystem

June 19, 2017

(Millbrook, NY) Each year, more than a million wildebeest migrate through Africa’s Serengeti Mara Ecosystem. While crossing the Kenyan reach of the Mara River, thousands perish. A new study, published today in the Proceedings of the National Academy of Sciences, is the first to reveal how wildebeest drownings impact the ecology of the iconic river.

Amanda Subalusky, a Postdoctoral Associate at the Cary Institute of Ecosystem Studies, is the paper’s lead author. She conducted the work while a graduate student at Yale University. Subalusky explains, “The Mara River intersects one of the largest overland migrations in the world. During peak migration, the wildebeest cross the Mara River multiple times, sometimes resulting in drownings of hundreds or thousands of wildebeest. Our study is the first to quantify these mass drownings and study how they impact river life.”

The research team conducted five years of field surveys and analyzed a decade of historical reports from the Mara Conservancy to determine the rate and frequency of wildebeest drownings in the Mara River’s Kenyan reach. On average, 6,200 wildebeest – representing 1,100 tons of biomass – succumb each year during migration, with mass drownings occurring in 13 of the last 15 years (2001-2015).

Co-author Emma Rosi, an aquatic ecologist at the Cary Institute, notes, “To put this in perspective, it’s the equivalent of adding ten blue whale carcasses to the moderately-sized Mara River each year. This dramatic subsidy delivers terrestrial nitrogen, phosphorus, and carbon to the river’s food web. First, fish and scavengers feast on soft tissues, then wildebeest bones slowly release nutrients into the system – feeding algae and influencing the food web on decadal scales.”

To reveal the fate of wildebeest carcasses, the researchers modeled in-stream consumption by fish and Nile crocodiles, scavenging by birds, nutrient uptake, and downstream transport. Stable isotope analyses of common fishes, camera monitoring of scavengers, and stable isotope analyses of biofilms (a mix of bacteria, fungi, and algae) on wildebeest bones all informed the fate of wildebeest nutrient inputs.

While wildebeest soft tissue decomposes in 2-10 weeks, their bones persist for upwards of seven years, acting as a long-term source of phosphorus. Rosi explains, “Mass drownings present a striking picture. Rotting animal flesh spikes the aquatic ecosystem with nutrients. But once carcasses disappear, bones – which make up nearly half of biomass inputs – continue to feed the river.”

When wildebeest carcasses were present, they comprised 34-50% of the diet of common fish. The most frequent terrestrial scavengers on carcasses were Marabou storks, white-backed vultures, Rüppell’s vultures, and hooded vultures, consuming 6-9% of soft tissues. Biofilms on wildebeest bones had a distinct isotopic signature, and made up 7-24% of the diet of three common fish species months after drowning events. Due to low metabolic rates, Nile crocodiles were estimated to eat just 2% of total carcass inputs.

Co-author David Post, an aquatic ecologist at Yale University, comments, “The Mara River is one of the last places on Earth left to study how the drowning of large migratory animals influences aquatic ecosystems. Many migratory herds, like bison, quagga, and springbok have been driven to extinction or remnant populations.”

With Subalusky adding, “The migration is currently underway in the Mara, having arrived early this year. What is happening there is window into the past, when large migratory herds were free to roam the landscape, and drownings likely played an important role in rivers throughout the world.”

Three chameleon species discovered in Africa


This video says about itself:

West Usambara Blade-horned Chameleon (Kinyongia multituberculata) in situ.

8 August 2015

Taken with Canon eos 70D at Irente Biodiversity Reserve, West Usambara Mtns. Tanzania.

From the University of Texas at El Paso in the USA:

Three chameleon species discovered

June 19, 2017

University of Texas at El Paso doctoral candidate Daniel Hughes liked to catch lizards when he was little, but never imagined he would be catching and discovering new species of chameleons. The Ph.D. candidate in UTEP’s Ecology and Evolutionary Biology program has discovered three new species of chameleons. The reptile trio, historically thought to be a single species, was found in different parts of the Albertine Rift in Central Africa.

The findings recently were published in Zoological Journal of the Linnean Society.

“We are hopeful that the formal descriptions of these three endemic chameleon species will be used to increase conservation awareness and galvanize transboundary protection efforts across these irreplaceable regions,” Hughes said.

The specimens were collected in the Democratic Republic of the Congo between 2009 and 2014, mainly by Hughes’ mentor Eli Greenbaum, Ph.D., associate professor of biological sciences. The location is rich with biodiversity, but because of political unrest, researchers have been reluctant to go there. Greenbaum has been traveling and conducting research in the area for about 10 years.

“We had this really nice dataset with samples collected all throughout the range of a particular species which meant we could really figure out its true diversity,” Hughes said. “We took to the next step and ultimately described three new species.”

Hughes joined Greenbaum three years ago in the field, and specifically came to UTEP to study under Greenbaum in 2013. The new scientist was able to describe the three new chameleon species after carefully analyzing geographical, morphological, and DNA data; a process that was followed by nearly two years of external confirmation.

Two of the new chameleons, Rugege Highlands Forest Chameleon (Kinyongia rugegensis), and Itombwe Forest Chameleon (Kinyongia itombwensis), are named after the mountain ranges in which they’re found. The third chameleon, Tolley’s Forest Chameleon (Kinyongia tolleyae), is named after herpetologist Krystal Tolley. Tolley, principal scientist at the South African National Biodiversity Institute in Cape Town, South Africa, has contributed significantly to chameleon research and first taught Hughes how to catch chameleons in Uganda.

“I think I went into shock when I found out, but also really happy,” Tolley said. “I have been working on chameleons for many years, and they really are my main topic of research. So to have a species named after me, for a group of animals where I’ve invested most of my research career is such a privilege. I’ve also been lucky enough to actually see this species in Uganda, together with both Danny and Eli. It’s a sassy little thing, which really makes it a good fit.”

Hughes said the Albertine Rift (AR) is not only geologically unique, it also harbors more endemic vertebrate species than any other area of similar size on continental Africa.

“In these remote regions that are sometimes thousands of miles away from many people, it can be hard to relate,” Hughes said. “So, hopefully with our work we can start to bridge that gap to broaden our awareness that everyone’s actions have implications for these species from threatened regions they may never see. If conservation efforts in the various countries of the Albertine Rift cannot rapidly improve, many rare and potentially other new species will be lost.”

There are 206 described species of chameleons on the planet and Hughes hopes to continue finding many more.

“A recent modeling study demonstrated that many habitats in the Albertine Rift, including those where the new species of chameleons are endemic, will likely be destroyed in the coming decades,” Greenbaum said. “As chronicled in my forthcoming book “Emerald Labyrinth: A Scientist’s Adventures in the Jungles of the Congo,” the coming years will almost certainly be the last opportunity to discover new species in the rapidly declining forests of Central Africa.”

Dinosaur age caecilian amphibian ancestor discovered?


This video says about itself:

19 June 2017

A new analysis of a pair of tiny fossils found in the 1990s has helped scientists to uncover the backstory of the most mysterious amphibian alive. Researchers used 3D X-rays to map out the remains of a now-extinct species that walked the Earth [220] million years ago. They found that the species is a long-missing amphibious link that expands the known history of frogs, toads and salamanders by at least 15 million years. Chinlestegophis jenkinsi (artist’s impression) was a tiny subterranean carnivore.

From Science News:

New fossils shake up history of amphibians with no legs

Tiny skulls and other bits hint at unexpected backstory for today’s snake-shaped caecilians

by Susan Milius

3:30pm, June 19, 2017

Newly named fossils suggest that a weird and varied chapter in amphibian deep history isn’t totally over.

Small fossils about 220 million years old found along steep red slopes in Colorado represent a near-relative of modern animals called caecilians, says vertebrate paleontologist Adam Huttenlocker of the University of Southern California in Los Angeles.

Caecilians today have long wormy bodies with either shrunken legs or none at all. Yet the nearly 200 modern species of these toothy, burrow-dwelling tropical oddballs are genuine amphibians. The fossil creatures, newly named Chinlestegophis jenkinsi, still had legs but could be the oldest known near-relatives of caecilians, Huttenlocker and colleagues suggest.

A popular view of the amphibian family tree has put caecilians on their own long, peculiar branch beside the ancient frogs and salamanders. But a close look at the new fossils suggests a much earlier split from ancestral frogs and salamanders, the researchers propose June 19 in Proceedings of the National Academy of Sciences. The move puts the caecilians into “a strange but incredibly diverse” group, the stereospondyls, Huttenlocker says. These species included elongated, short-legged beasts with heads shaped like toilet lids.

Among the many stereospondyls, Huttenlocker speculates that caecilians came from “an aberrant branch of miniaturized forms that went subterranean.” And today’s legless burrowers could be this once-flourishing group’s sole survivors.

Spineless creature in Washington, DC swamp studied


Stygobromus hayi, photo by Michelle Brown

From the University of Illinois at Urbana-Champaign in the USA:

Spineless creature studied in DC swamp

Its name is Stygobromus hayi, the Hay’s Spring amphipod. It is spineless. It lacks vision. It is an opportunistic feeder, consuming whatever resources are available — perhaps including the remains of its own kind.

That is where its similarities to some of Washington, D.C.’s more notorious megafauna end. And while this tiny creature has been the subject of scientific inquiry in recent years, researchers report on a way to survey it without threatening its existence, as other studies had done.

The Hay’s Spring amphipod lives in swampy areas called seepage springs where groundwater sometimes spills out onto the surface of Rock Creek Park, in Washington, D.C., its only known home in the world. Because it is so rare, and perhaps also because of its prestigious ZIP code and proximity to the National Zoo, this tiny crustacean is on the U.S. endangered species list.

“Yes, it’s small, it’s white, it’s eyeless, it lives underground,” said Matthew Niemiller, an ecologist with the Illinois Natural History Survey who led a recent study to search for the creature in its Rock Creek Park home. “It’s not a cute, cuddly or charismatic species. But we’re still learning more and more about groundwater ecosystems. And there is evidence that these crustaceans are important indicators of groundwater quality, and may play important roles in water purification and nutrient cycling over time.”

The Hay’s Spring amphipod‘s subterranean habitat makes it particularly difficult to study, Niemiller said.

“To find out where species are located and how many there are, we have to disturb the site,” he said.

This normally involves sifting through waterlogged leaves in muddy seepage areas, where underground springs leak out to the surface.

“And because these critters are small — no more than a centimeter long — and a couple of other species look very similar to S. hayi, we would have to sacrifice any individuals we find and take them back to the lab to identify them,” he said. “Since this is an endangered species, that’s something we don’t want to do.”

Niemiller and his colleagues decided to try a different approach, called eDNA. They sampled water in seepage springs where S. hayi and other Stygobromus species had previously been sighted and in others where they had not. The team filtered the water on site, returning to the lab to check their filters for the animal’s DNA.

“This environmental DNA approach has successfully detected larger aquatic animals like salamanders, but no studies had previously used this technique to hunt for invertebrates in groundwater,” Niemiller said.

All creatures shed their DNA into the environment, but the researchers didn’t know if their target animal would slough off enough genetic material to be detectable in their samples. Water quality also was an issue: The seepage springs are muddy and loaded with acidic plant tannins, which can inhibit polymerase chain reaction, the key method for amplifying and detecting DNA in environmental samples.

The researchers overcame the latter problem, however, using chemicals known to remove potential PCR inhibitors.

Their analysis detected S. hayi DNA in samples from three sites where the creature had been seen before, and in a fourth new seepage spring nearby. The researchers also found the DNA of a closely related species, Stygobromus t. potomacus, in four of 10 springs sampled.

“We now know that eDNA is going to be a really worthwhile tool — at least for aquatic species in difficult-to-access habitats,” Niemiller said. “You could go to a spring outflow, take a water sample, and see what you might detect there with a limited outlay of labor, time and money.”

The method has its limitations, however. Environmental DNA sampling can tell researchers whether something is present or absent, but not how many of the targeted organisms are present.

“We also don’t know how long DNA persists in these systems and whether we’re detecting animals that are still alive,” Niemiller said.

The new study demonstrates, however, that this is a viable method to supplement other, more detailed studies of aquatic organisms, he said.

“As funding becomes tighter, we need to think about more efficient ways to monitor and protect these species,” he said.

Jewel scarab beetles look like gold, why?


This video says about itself:

Jewel Scarab in Costa Rica -Chrysina

4 February 2014

Here is a video of a lovely creature I came across during a rain forest exploration. I love insects and this one really took the cake. It’s body was was a like a mirror that reflected all the colors around it.

From the University of Exeter in England:

Secret of why jewel scarab beetles look like pure gold, explained by physicists

‘All that glitters is not gold,’ finds research program into way jewel beetles reflect light

June 15, 2017

The secrets of why Central American jewel scarab beetles look like they are made from pure gold, has been uncovered by physicists at the University of Exeter.

The ornate beetles, which have a brilliant metallic gold colour, are highly valued by collectors. But until now the reasons behind their golden iridescent hue, have not been fully understood.

University of Exeter physicists specialising in colour and light have done experiments exploring the origin of the scarab beetles’ striking metallic golden appearance, showing that the golden beetles have a unique ‘optical signature’. The structure of the beetle and its armour uniquely manipulates the way the light is reflected so that it looks like pure gold.

Their results are published in the Journal of the Royal Society Interface.

Professor Pete Vukusic, a physicist specialising in light and colour, led the research which involved experiments and advanced modelling. He found that the golden appearance is due to the high reflectiveness of the beetles’ exoskeleton, which also manipulates a property of the light called its polarisation: the orientation of the reflected light wave‘s oscillations.

The scientists mapped the optical signature of the beetle’s Chrysina resplendens‘ colour, and found it was unusually ‘optically-ambidextrous’, meaning that it reflects both left-handed and right-handed circularly-polarised light.

Professor Vukusic said: “The brilliant golden colour and distinctive polarised reflection from the scarab beetle Chrysina resplendens sets it completely apart from the hundreds of thousands of other beautiful and brightly coloured animals and plants across the natural world. Its exoskeleton has a bright, golden appearance that reflects both right-handed and left-handed circularly-polarised light simultaneously. This characteristic of Chrysina resplendens appears to be an exceptional and wonderfully specialised characteristic in currently known animals and plants. It will serve as a valuable platform from which bio-inspired optical technologies can spring.”

The golden jewel beetle is prized by collectors because of its resemblance to the precious metal.

Other scarab beetles, valued by ancient cultures such as the Egyptians for use as amulets which were sometimes wrapped in the bandages of mummies, are a jewel-like green and blue colours. The vast majority of brightly-coloured beetles tend to be green and do not reflect polarised light. These beetles, in comparison to the brilliant golden colour of Chrysina resplendens, lack much more specialised aspects of their exoskeleton’s finely detailed structure.

Dr. Ewan Finlayson, research fellow on the project, said: “We were drawn to the study of this jewel scarab not only by its striking metallic golden appearance, but also by its ability to control a less obvious property of the reflected light: the polarisation. We have learned that there is great subtlety and detail to be found in these optical ‘signatures’ and in the elaborate natural structures that generate them.”

The golden jewel scarab beetle Chrysina resplendens, mainly found in the Americas, has evolved an exoskeleton that contains intricate nano-structures that are responsible for its appearance.

The spacing of the repeating layers of the nano-structures is found to vary over a specific range through the exoskeleton — a key property that causes the simultaneous reflection of a range of visible colours. It is this fact that explains the very bright reflection as well as the golden hue.

The nano-structured exoskeleton is composed of natural materials including chitin and various proteins. In addition to their brilliant reflectiveness, these structures are remarkable in the way they manipulate the way polarised light is reflected.

Their nanostructures produce circularly-polarised light, where the orientation of the light’s oscillations rotate as the light travels. The two possible directions of rotation are referred to as left handed and right handed.

The experiments build on the work of an early American scientist called Michelson who, in 1911, looked at the polarised reflection from many different Chrysina beetles, and on the work of Anthony Neville (then at Bristol University) in 1971, who began looking more closely at Chrysina resplendens.

There are around 100 species of Chrysina jewel scarab, which are found exclusively in the New World, mostly in Mexico and Central America. The species Chrysina resplendens is found in Panama and Costa Rica. Chrysina scarabs typically live in mountain forests. The larvae feed on rotting logs of various tree species, while the adults feed on foliage. The larval form lasts for several months to a year, and pupation takes a month or two. After the adult emerges it lives for about a further three months, although this span probably varies between species.

One explanation for the highly-reflective appearance of the beetle exoskeleton is crypsis: the ability of the animal to blend in to its surroundings.

Dr Martin Stevens, Associate Professor of Sensory and Evolutionary Ecology at the University of Exeter and an expert in animal vision, colour change and camouflage, said: “It is not absolutely clear why these beetles are a bright golden colour, but one option is that it somehow works in camouflage under some light conditions. The shiny golden colour could also change how the beetle is seen as it moves, potentially dazzling a would-be predator. There are many species which are iridescent but jewel beetles are one of the most charismatic and brightly coloured, and their colour might be used in mating. However, it is not clear how other beetles see the gold colour and reflected light. Many small mammals would not be able to distinguish the golden colour from reds, greens, and yellows, but a predatory bird would likely be able to see these colours well.”