Fossil of most primitive 4-legged creature found in Latvia; lived eons before dinosaurs
By SETH BORENSTEIN AP Science Writer
WASHINGTON June 25, 2008
Scientists unearthed a skull of the most primitive four-legged creature in Earth’s history, which should help them better understand the evolution of fish to advanced animals that walk on land.
The 365 million-year-old fossil skull, shoulders and part of the pelvis of the water-dweller, Ventastega curonica, were found in Latvia, researchers report in a study published in Thursday’s issue of the journal Nature. Even though Ventastega is likely an evolutionary dead-end, the finding sheds new details on the evolutionary transition from fish to tetrapods. Tetrapods are animals with four limbs and include such descendants as amphibians, birds and mammals.
While an earlier discovery found a slightly older animal that was more fish than tetrapod, Ventastega is more tetrapod than fish. The fierce-looking creature probably swam through shallow brackish waters, measured about three or four feet long and ate other fish. It likely had stubby limbs with an unknown number of digits, scientists said.
This is a video of two black-necked grebes in the Netherlands.
Within Meijendel nature reserve, there is a specially protected area called Kikkervalleien. It is open the public only for one day a year, usually in June. This year, that one day was today.
Before arriving there: two adult black swans with young, near the Valkenburgse meer.
Immediately after the Kikkervalleien entrance: two black-necked grebes swimming.
On ragwort plants, black and yellow striped caterpillars. They are caterpillars of the Cinnabar moth.
A lady working for the nature reserve shows us a very young natterjack toad, which was a tadpole not long ago. Also many still very small common frogs. Later, also an adult common toad there. There are also invertebrates in the water here, including great pond snails.
On the water’s edge of a small shallow dune lake, many very small common frogs. Swimming in the water: their brothers and sisters, still in the tadpole phase.
And this is a video of a kingfisher, also near Crailo nature bridge.
We did not see either of those two species when we went to that area today; however, we did see many other beautiful animals and plants.
The young grey lag geese and coots had become much bigger than last time, though still a bit smaller than the adults.
Sounds of edible frogs and reed warblers. And of a little grebe. I had heard that sound before on this lake, but had not seen the dabchick making it. Neither did I this time.
Researchers from the University of Sydney have found that cane toads have caused a 75 per cent drop in freshwater crocodile numbers in the Northern Territory’s Victoria River District (VRD).
The researchers say this is first time that extensive research has confirmed anecdotal reports about the introduced pests’ effect on the native predator.
Researcher Doctor Mike Letnic, says they studied crocodile populations before and after the cane toad arrived in the district.
He says the worst damage was in the arid areas during the dry season.
“The rivers are essentially an oasis and the crocodiles live in the river, but the landscape is dry and during the dry season the cane toads congregate on the edge of the water where they encounter the crocodiles.
“They turn the table on the predator.”
He says freshwater crocs are more susceptible to the pest than their saltwater cousins.
“Saltwater crocodiles appear to be more resistant to the toxin than the freshwater crocodiles and the reason for that is probably because saltwater crocodiles occur throughout southern Asia where some toad species also exist, so it’s likely that the saltwater crocodiles evolved with species similar to cane toads.”
From snakes and frogs to giant squirrels, this Southeast Asian island is home to a greater variety of flying animals than any other place on Earth
IT WAS AN ORDINARY looking snake, moving along a tree branch in the dappled light of Borneo’s rain forest. Suddenly, dropping off the branch, it hung by its tail and pushed off, leaping into the damp air. Was this snake really flying? It seemed like a wild dream—or to someone with a fear of snakes, perhaps the worst nightmare. But there it was, changing shape as it began to drop, ribs spreading and body flattening, swimming through the air like a water snake crossing a pond, but with its body flat as a ribbon. The snake, Chrysopelea paradise, or paradise tree snake, angled down and landed on a lower branch.
The scene could have been witnessed only in the rain forests of Southeast Asia, where there are several kinds of flying snakes. And snakes are just the first on a list of curious creatures that take to the air to get from tree to tree. More than 60 gliding species inhabit the region’s forests, 33 of them on Borneo alone. In addition to snakes, the island is home to flying lemurs, lizards, squirrels, geckos and frogs.
Though they’re called “flying,” these animals cannot really fly like birds or bats that propel themselves through the air. Yet they do much more than simply parachute out of a tree and plop to the ground. The animals travel like hang gliders, subtly shifting body weight or adjusting tails and limbs to steer a controlled flight path through the canopy labyrinth. And all have body structures that increase surface area, making them better airfoils.
Teams turned up 1,364 unique plant and animal species by noon today–more than twice the hoard volunteers ID’d in the same time at Rock Creek Park last year. More still will come in the days ahead as bio-sleuths resolve the identities of a slew of mystery species.
Over 11,000 people in Australia were hospitalised because of a venomous bite or sting between 2002 and 2005, according to a report released today by the Australian Institute of Health and Welfare (AIHW).
Spider bites accounted for a third of those hospitalisations, and the vast majority of spider bite cases were attributed to red-backs (59 per cent).
Clare Bradley of the AIHW’s National Injury Surveillance Unit, said that 3 in 10 bite and sting hospitalisations were because of wasp and bee stings.
‘Bee stings alone accounted for almost 25 per cent of all bite and sting hospitalisations,’ she said.
Bites from snakes accounted for just 15 per cent of bite and sting hospitalisations.
‘Just over half of those snake bite cases were attributed to brown snakes (54 per cent). Black snake (15 per cent) and tiger snake (11 per cent) bites were also common,’ Ms Bradley said.
Other venomous bites and stings requiring hospitalisation in 2002-05 were attributed to venomous arthropods, such as ants, centipedes, and millipedes (10 per cent of cases) and venomous marine animals, such as jellyfish and stingrays (9 per cent).
The report, Venomous bites and stings in Australia to 2005, also revealed strong correlations between the rate of venomous bites and stings and place of residence.
Not surprisingly, residents of major cities had the lowest rate while residents of the very remote regions of Australia had the highest.
The highest rates of hospitalised bite and sting cases occurred in the Northern Territory, Queensland, South Australia and Western Australia, while the Australian Capital Territory and Victoria had the lowest rates.
Their research is published in Thursday’s issue of the journal Nature.
The fossil that links modern frogs and salamanders proves the previously disputed fact some modern amphibians, frogs and salamanders, evolved from one group of ancient primitive amphibians called “temnospondyls.”
“This fossil is the most like the modern amphibian that you find and it’s from incredibly ancient times,” said principal investigator Jason Anderson, an assistant professor of veterinary anatomy at the University of Calgary in Canada who specializes in vertebrate paleontology.
“So what this does is provide conclusive evidence that frogs and salamanders have an origin among one particular group of extinct fossil amphibians,” Anderson said.
“This fossil falls right into a gap in the fossil record between one archaic group of amphibians and the earliest examples of the modern amphibians, frogs and salamanders.”
The fossil was first collected in Texas by the late Nicholas Hotton, a paleontologist with the Smithsonian Institution, in 1995. It was rediscovered in the collections of the National Museum of Natural History in Washington, D.C., in 2004.
Dubbed Gerobatrachus hottoni (Hotton’s elder frog), the animal looked somewhat like a salamander with a stubby tail and froglike ears.
“It’s got a great big froggie ear and it’s reduced the number of vertebrae in its back … but like salamanders, it shares a particular fusion of some ankle bones,” said Anderson.
“The skull itself, you look at the skull and it is almost what you’d expect to see in a frog, really lightly built, kind of like soaring, flying buttresses on a cathedral, long arching struts, really broad and wide,” he explained.
The researchers believe the discovery is important not just for science, but also for the general public.
