Sydney spiders bigger than Australian outback spiders


This video from the USA says about itself:

6 June 2011

Get a behind-the-scenes look at this history and creation of this dazzling textile—the only one of its kind in the world—made from the strands of silk from over one million of Madagascar’s golden orb spiders. On view at the Art Institute of Chicago through October 2011.

From Wired magazine:

Cities Are Making Spiders Grow Bigger and Multiply Faster

By Nick Stockton

08.20.14, 2:00 pm

Something about city life appears to be causing spiders to grow larger than their rural counterparts. And if that’s not enough to give you nightmares, these bigger urban spiders are also multiplying faster.

A new study published today in PLOS One shows that golden orb weaver spiders living near heavily urbanized areas in Sydney, Australia tend to be bigger, better fed, and have more babies than those living in places less touched by human hands.

The study’s authors collected 222 of the creatures from parks and bushland throughout Sydney, and correlated their sizes to features of the built and natural landscape. …

To measure urbanization, the authors looked primarily at ground cover throughout the city, at several scales, where they collected each spider: Are surfaces mostly paved? Is there a lack of natural vegetation? Lawns as opposed to leaf litter?

“The landscape characteristics most associated with larger size of spiders were hard surfaces (concrete, roads etc) and lack of vegetation,” said Elizabeth Lowe, a Ph.D student studying arachnids at the University of Sydney.

Humped golden orb weavers are a common arachnid along Australia’s east coast. They get their name from their large, bulging thorax, and the gold silk they use to spin their spherical webs. They typically spend their lives in one place, constantly fixing the same web (which can be a meter in diameter). Each web is dominated by a single female, though 4 or 5 much smaller males usually hang around the edges of the web, waiting for an opportunity to mate (only occasionally does the female eat them afterwards).

Paved surfaces and lack of vegetation mean cities are typically warmer than the surrounding countryside. Orb weavers are adapted to warm weather, and tend to grow bigger in hotter temperatures. The correlation between size and urban-ness manifested at every scale. Citywide, larger spiders were found closer to the central business district. And, their immediate surroundings were more likely to be heavily paved and less shady.

More food also leads to bigger spiders, and the scientists believe that human activity attracts a smorgasbord of orb weavers’ favorite prey. Although the study wasn’t designed to determine exactly how the spiders were getting bigger, the researchers speculate that things like street lights, garbage, and fragmented clumps of plant life might attract insects. They also believe that the heat island effect might let urban spiders mate earlier in the year, and might even give them time to hatch multiple broods.

The orb weavers could also be keeping more of what they catch. Because they are such prolific hunters, orb weavers’ webs are usually home to several other species of spiders that steal food. The researchers found that these little kleptos were less common in webs surrounded by pavement and little vegetation.

Lowe says quite a few species of spider are successful in urban areas, and she wouldn’t be surprised if some of these other species were also getting bigger. Despite how terrifying this sounds, she assures me that this is actually a good thing. “They control fly and pest species populations and are food for birds,” she said.

Save amphibians, worldwide alliance


This video says about itself:

Together We Can Save Amphibians

28 November 2013

The Amphibian Survival Alliance is the world’s largest partnership for the protection of amphibians. Our approach is effective and efficient — by creating new reserves in priority sites worldwide we are able to save entire species with modest and targeted investment. Over the next six months we will triple every dollar donated through WorthWild, with a goal of securing 100,000 football fields-worth of amphibian habitat in the Philippines, Madagascar, Ecuador and beyond. Learn more here. Help Spread The Word. Share This Initiative!

From Wildlife Extra:

World’s largest partnership for amphibian conservation formed

Amphibian conservation is proving to be one of the most important conservation challenges of this century, with alarming implications for the health of ecosystems globally.

Which is why Fauna & Flora International (FFI) has joined the Amphibian Survival Alliance (ASA) in agreeing to support conservation actions and research to address the global amphibian extinction crisis.

Together they make the world’s largest partnership for amphibian conservation.

Amphibians are key indicators of environmental change and biological health. Their permeable skin absorbs toxic chemicals, which makes them more susceptible to environmental disturbances on land and in water.

Breathing through their skin means they are more directly affected by chemical changes present in our polluted world – so the health of amphibians such as frogs is thought to be indicative of the health of the biosphere as a whole.

Frogs have survived in more or less their current form for 250 million years – surviving asteroid crashes, ice ages and other environmental disasters and disturbances.

They have a natural extinction rate of about one species every 500 years, but shockingly, since 1980 up to 200 species have completely disappeared.

Using a priority-actions framework provided by the IUCN SSC Amphibian Specialist Group, this new partnership will facilitate the implementation of conservation initiatives at all scales, from local to global.

“We are delighted to have Fauna & Flora International join the ASA,” said Don Church, Executive Director of the Amphibian Survival Alliance.

“FFI’s long tradition of achieving conservation impact in the field is exactly what amphibians need now.”

Aldrin Mallari, FFI’s Philippines Country Director, added, “We are very happy to have found allies in ASA, to jointly address the issues of such excellent ambassador species for fragile ecosystems.”

Hop on to Amphibian Survival Alliance to find learn more about how organisations like FFI and others around the world are working together within the ASA for amphibians, the environment and people.

Egyptian fossil relatives of Madagascar bats discovered


This video from the USA says about itself:

26 Sep 2012

Dr. Nancy Simmons specializes in the morphology and evolutionary biology of bats (Chiroptera). Together with several collaborators, she is developing a data set of morphological characters scored in species representing all major clades of bats. These data include new information gained from high-resolution CT scans of rare bats and are being combined with DNA sequence data to develop a robust higher-level phylogeny for Chiroptera.

With collaborators, she is doing an in-depth study of the evolution of megabats — flying foxes and their relatives — using both molecular and morphological data. Dr. Simmons is also working with an expert on echolocation behavior to develop a method for coding features of echolocation calls for phylogenetic analysis.

From the American Museum of Natural History in the USA:

Sucker-Footed Bat Fossils Broaden the Bat Map

by AMNH on 02/04/2014 05:00 pm

Today, Madagascar sucker-footed bats are found only on their island home, but new research from the American Museum of Natural History and Duke University shows that wasn’t always the case. The discovery of two extinct relatives in northern Egypt suggests the unusual creatures, which evolved sticky footpads to roost on slick surfaces, are primitive members of a group of bats that evolved in Africa and ultimately went on to flourish in South America.

A team of researchers described the two bat species from several sets of fossilized jawbones and teeth unearthed in the Sahara. The findings, reported on February 4 in the journal PLOS ONE, represent the first formal description of the family in the fossil record and show the sucker-footed bat family to be at least 36 million years older than previously known.

“We’ve assumed for a long time that they were an ancient lineage based on DNA sequence studies that have placed them close to very old groups in the bat family tree,” said Nancy Simmons, co-author on the study and a curator in the Department of Mammalogy.

But until now, scientists lacked any fossil evidence to confirm it.

Today, the sucker-footed bats consist of two species, Myzopoda aurita (see images of these bats here) and M. schliemanni, endemic to Madagascar. In contrast to almost all other bats, they don’t cling upside-down to cave ceilings or branches. Sucker-footed bats roost head-up, often in the furled leaves of the traveler’s palm, a plant in the bird-of-paradise family. To stick to such a smooth surface, the bats evolved cup-like pads on their wrists and ankles. Scientists previously suspected the pads held the bats up by suction, but recent research has demonstrated the bats instead rely on wet adhesion, like a tree frog.

The two extinct species, Phasmatonycteris phiomensis and P. butleri, date to 30 and 37 million years ago, respectively, when the environment was drastically different. Northern Africa was more tropical, said Dr. Simmons, and home to a diverse range of mammals, including primates and early members of the elephant family.

“The habitat was probably fairly forested, and there was likely a proto-Nile River, a big river that led into the ancient Tethys Ocean,” said Gregg Gunnell, director of the Duke University Lemur Center‘s Division of Fossil Primates and a co-author on the paper.

The fossilized teeth imply that, like their living relatives, the ancient bats fed on insects. It’s impossible to know from the fossils if the extinct species had already evolved their characteristic sucker-feet, but the teeth shed light on another aspect of bat evolution. The presence of sucker-footed bats in Africa at least 37 million years ago supports the theory that this family is one of the most primitive members of a lineage that now dominates South America.

From vampires to fruit- and nectar-eaters to carnivores, the majority of South America’s bats belong to one large superfamily, known as Noctilionoidea.

“We think that the superfamily originated in Africa and moved eastward as Gondwana was coming apart,” Gunnell said. “These bats migrated to Australia, then actually went through Antarctica and up into South America using an ice-free corridor that connected the three continents until about 26 million years ago.”

According to this hypothesis, the sucker-footed bat fossils showed up right where scientists expected to find them: at the literal and figurative base of the Noctilionoidea family tree.

“Now, we can unambiguously link them through Africa,” Simmons said.

You can read the scientific paper here.

Like Darwin’s Finches, But Weirder, Bat Faces Showcase Amazing Adaptations: here.

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Prehistoric frog’s anti-dinosaur armour?


This video is called The Evolution of Amphibians.

From LiveScience:

Primeval ‘Devil Frog’ May Have Sported Anti-Dinosaur Armor

By Tia Ghose, Staff Writer

January 29, 2014 10:00am ET

An ancient, predatory creature known as the devil frog may have looked even scarier than previously thought.

The monster frog, Beelzebufo ampinga, lived during the Cretaceous Period in what is now Africa, and sported spiky flanges protruding from the back of its skull and platelike armor down its back, almost like a turtle shell.

“We knew it was big; we knew it was almost certainly predatory,” said study co-author Susan Evans, a paleontologist at the University College London. “What the new material has shown us is that it was even more heavily armored than we imagined.”

The massive frog’s spiked body armor may have helped it fend off the dinosaurs and crocodiles that prowled during that time. [See Photos of the Devil Frog and Other Freaky Frogs]

Elusive lineage

The researchers first discovered a few bone fragments from a mystery frog in Madagascar in 1998, but it wasn’t until 2008 that they had enough pieces to identify the species, which they dubbed the devil frog, or Beelzebufo ampinga. The massive frog lived between 70 million and 65 million years ago.

When the team analyzed the frog’s morphology, they found that physically, it fit in with a family of horned frogs called the Ceratophryidae, which are now found only in South America.

But to reach Madagascar from South America, the frogs would have needed to hop along a passageway, possibly through Antarctica, that linked the two landmasses. But that route was submerged underwater by 112 million years ago, Evans said.

That would mean that devil frogs must have diverged from their South American cousins prior to that submergence, pushing back the origin of Ceratophryidae by more than 40 million years, Evans said.

More specimens

Over the course of the next five years, the team found several more bone fragments of Beelzebufo ampinga. In the new study, they combined all of the fragments to do a much more complete reconstruction of the devil frog.

The new analysis confirms the frog’s lineage in the Ceratophryidae family. It also downgrades the amphibian’s size — instead of being the biggest frog that ever lived, it may be closer to the size of an African bullfrog, which grows to about 10 inches (25.4 centimeters) across.

Even so, the analysis reveals that the devil frog was even fiercer-looking than previously thought. Past studies had suggested it had a huge, globular head; sharp teeth; and short back legs, but the spiky flanges and the plates embedded in its skin were a surprising discovery.

The frogs may have hunted like African bullfrogs, hiding before pouncing on a small mammal.

It’s not clear what the frogs used the body armor for, but one possibility is that the sculptured bones may have been an adaptation to a dry environment that allowed the frogs to burrow underground, where they were less likely to bake in the hot sun, Evans said.

But the armor may also have been protection.

“There were an awful lot of things roaming around that would have liked a bite out of a big, juicy frog,” such as dinosaurs, crocodiles and even strange mammals that once lived on the Gondwana supercontinent, Evans told LiveScience.

The findings were published Jan. 28 in the journal PLOS ONE.

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