Extinct Marine Animals

Here you can find out about any extinct animals that lived underwater, like the massive Liplerodon to tiny Ammonites.

Ammonites

The Ammonites were a group of shelled sea creatures that mysteriously disappered at the same time as the dinosaurs.  Ammonites were invertebrates, they had no backbone, plus, if you have a very supportive shell, there is no need for one.  Ammonites were molluscs, but molluscs aren't all extinct, in fact there are still plenty such as mussels, snails, octopuses and squid.  Ammoites grew to as big as 1m in diameter.  Ammonites lived from the early Devonian period to the end of the Creataceous period, about 380-65 million years ago.  Ammonites probably lived in warm, shallow, tropical areas of the ocean, ideal for plenty of other marine life.

Ammonites were carnivors, their diet consited of small fish, munching them with a powerful beak, as well as other small marine life.  Ammonites were popular on larger carnivorous marine life's menu's though, such as icthyosaurs, but they would either have to pull it out from the shell, or have jaws powerful enough to crush it.

Wonder how Ammonites move?  Well, they moved by squeezing water and expelling it out, meaning they could dart in all different directions, making it hard for preadators.  Ammonites didn't sink to the ocean floor because their shell was filled with chambers of water and gas, making them buoyant.

Interesting Facts:

• Ammonites closest living relative are the rare, deep Pacific dwelling Nautilus.
• Ammonite fossils are commonly found in rocks, their distinctive curly shell giving them away.
• Ammonites all layed eggs, the males mated with the females, then the females placed the eggs on a hard surface until they hatched.

Basilosaurus

Basilosaurus wasn't a Dinosaur or Marine Reptile, it was a Whale; a mammal.  It lived from about 40-36 million years ago in the Late Eocene period and weighed about 50-60 tonnes.  Females could grow to 15m long and the males 18; though larger ones may have grew to 20.  Basilosaurus was very long but suprisingly had a small head for it's size.

Basilosaurus was a carnivore, eating meat.  It ate fish, squid, sharks and somtimes maybe even Dorudon calves when they were born.

Basilosaurus was first discovered in 1843 in Louisiana, USA.  Basilosaurus has also been found in Fayum deposits in Egypt.  In the desert of Eygypt there is a place called 'The Valley Of The Whales', where whale skeletons erode out of the sand.  Two kinds of whales are found there, Basilosaurus being one of them.  When Basilosaurus was first discovered, it was mistaken as a sea serpent!

Interesting Facts: 

• Basilosaurus was one of the first giant whales.
• Basilosaurus was closely related to Dorudon.
• Basilosaurus, as well as Dorudon, had a pair of tiny back legs that were used for mating.  Whales now haven't got these legs.
• Basilosaurus, like all whales, started off as small, land-dwelling mammals.

Cephalaspis

Cephalaspis was a fish-like creature that lived during the Silurian-Devonian Periods,  around 400 million years ago.  They were around 20-30cm in length and had tough, heavy headgear and hard, thick scales.  Cephalaspis were one of the first creatures to have memory as well as complex brains.  With memory, they could also navigate and remember landmarks.  They were very smart creatures for their age.

Cephalaspis were peaceful herbivores, feeding off algae.  They would suck the algae up through their jawless mouth.  On the other hand, predators were a huge problem, sea scorpions such as Brontoscorpio, and large artropods such as Pterygotus, all fed on Cephalaspis.  But Cephalaspis had one advantage on it's side, they used a very different way of sensing danger.  Cephalaspis used an early warning system, just above the bottom of their headgear were some special scent glands, these glands would detect even the smallest vibrations in the water, and they would swim away.

Reproduction was a whole different aspect from the life of a Cephalaspis.  They would first mate, and then the females would make a long journey to a spawning pool.  Using navigation and memory, Cephalaspis would make it to the spawning pool and lay their eggs.  The eggs were small and were layed quickly, and then they would make the journey back to the open ocean.

Interesting Facts: 

• Believe it or not, Cephalaspis were actually an ancestor of us.
• Due to their headgear, Cephalaspis couldn't swim very fast for long, and would have to rest frequently.

Liopleurodon

Imagine a 16-25m long predator with a 3 metre long jaw and 4 metre long head and you get Liopleurodon.  It is one of the largest carnivores to live on this Earth.  It is a pliosaur, or short necked plesiosaurs.  With four long flippers, it was a very strong swimmer, so strong that it could push it's 150 tonne body through the water easily.  

Liopleurodon were massive carnivores eating any kind of meat the sea could throw at them.  Such as icthyosaurs, such as opthalmosaurus, plesiosaurs, such as cryptoclidus, hyobodus sharks and more, crushing then easily with it's powerful jaws.

Liopleurodon lived from about 165 to 150 million years ago in the Late Jurassic period.  Most Liopleurodon fossils have been found in the UK and Germany.

Interesting Facts: 

• Liopleurodon skulls show that it could sample the water sterio through it's nostrils, just like a tracking device to track down it's next meal.
• Liopleurodon's teeth were twice as long as Tyrannosaurus'. Source

  

  What do jellyfish eat?

"Predator" Corals Eat Jellyfish

Sorry, kids - scientists have not discovered the first known bubblegum-blowing sea creature. But they have found the only known corals to eat adult jellyfish, a new study says. 

Opening wide- yes, that's a mouth - a mushroom coral ingests a roughly 4-and-a-half-inch-wide (12-centimeter) moon jellyfish (pictured) in the Red Sea.

And this coral wasn't alone. The study, led by scientists from Israel's Bar-Ilan University and Tel Aviv University, witnessed other corals dining on the jellyfish.

Marine ecologist Jennifer Smith, who wasn't part of the study, agreed the find was unique, though she's "not entirely surprised."

Mushroom corals, which have soft bodies, have no eyes and can barely move of their own accord, marine ecologist Jennifer Smith.

"When you're dependent on things drifting [for food], anything helps," the Scripps Institution of Oceanography professor added. "You'll take any opportunity, as long as it doesn't kill you." 

What do jellyfish eat?

Weird Giant sunfish reveal secrets

We finally know why a huge, odd and enigmatic fish likes to sunbathe

The face of an ocean sunfish certainly leaves an impression.So too does its size; they are the largest bony fish in the world, ranging from one to four metres across, and weighing up to a tonne.And their name?

They are called sunfish because they spend almost half their day basking motionless at the ocean's surface, seemingly catching some rays. 

But until now it was not understood why they sunbathed, or exactly what they get up to in the deep ocean.

ew research shows that they forage for marine hydrozoans (Greek for sea serpent), which are small groups of predatory animals related to jellyfish. The fish take siphonophores, a type of hydozoan, most frequently at depths of between 50-200m. After their hunt they go back to the surface to top up their body temperatures by basking in the sun.

It's the first evidence that sunfish graze on these creatures in deep water. It was also previously believed they only ate jellyfish.A team led by Itsumi Nakamura of the University of Tokyo, Japan, caught several sunfish off the country's coast, around Funakoshi Bay, and attached thermometers to measure changes in their body temperatures.

They also attached cameras with lights on them, to gain insight into exactly what the fish were hunting. After four to six days these instruments naturally separated from the sunfish, allowing the researchers to collect and analyse the data.

The research, published in the journal Animal Ecology, uncovered that ocean sunfish swam back and forth between the surface and deep water during the day. Their cycles of diving deep and then warming at the surface helped to maximize their foraging time. Each time they "sunbathed" it regulated their body temperature.

Nakamura was also surprised to find just how quick the warming process was. "Beyond our assumption, their body temperature increased rapidly during surface warming, suggesting they have some physiological mechanisms to increase heat gain from the surrounding water."

This explains why larger sunfish can forage for longer, adds Nakamura.

It also provides a possible answer to why they have such a large body – as it serves to help them adapt to their hunting environment, losing heat very slowly.
The sea giants only hunt during the day. At night, they stayed at shallower depths of about 20m.

The discovery is a reminder that the deep sea is "still a frontier" says Nakamura, and only by increasingly observing the ocean depths will we unlock it secrets.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 1th - Megalodon

1th - Megalodon

One of the largest predators in marine history and one of the largest sharks ever recorded, Megalodons were as terrifying as they came.Megalodons prowled the depths during the Cenozoic Era, 28 – 1.5 million years ago, and were a much bigger version of the great white shark, an apex predator of today’s oceans.

But while our great whites only reach a maximum length of 20 feet (6m), Megolodons could grow to 65 feet in length (20m) – longer than a school bus!Source

What do jellyfish eat?

Top of prehistoric sea monsters. 2th - Liopleurodon

2th - Liopleurodon

If the Liopleurodon was huge, than Mosasaurus was colossal.Fossil evidence suggests that Mosasaurus could reach as much as 50 feet (15m) in length, making it one of the largest marine predators of the Cretaceous period. 

Mosasaurus’s head was like that of a crocodile, lined with hundreds of razor sharp teeth which could kill even the most well-armored enemies.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 3th - Liopleurodon

3th - Liopleurodon

Liopleurodon was a marine reptile measuring in at more than 20 (6m) feet in length. It mostly lived in the seas that covered Europe during the Jurassic period, and it was one of the top predators around. Its jaws alone are believed to have been over 10 feet long – roughly the distance from the floor to the ceiling.

With teeth that big, it’s easy to see why Liopleurodon dominated the food chain.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 4th - Tanystropheus

4th - Tanystropheus

While Tanystropheus was not strictly marine, its diet was mainly fish and scientists think it spent most of its time in the water. Tanystropheus was a reptile that could reach 20 feet (6m) long, and it is thought to have been alive during the Triassic period nearly 215 million years ago.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 5th - Thalattoarchon Saurophagis

5th - Thalattoarchon Saurophagis

Only recently discovered, T. saurophagis was the size of a school bus, reaching nearly 30 feet (9m) long. It is an early species of ichthyosaur that lived during the Triassic period, 244 million years ago. Because they were alive shortly after the Permian extinction (Earth’s largest mass extinction, when 95% of marine life is thought to have been wiped out), its discovery is giving scientists new insights into the quick recovery of the ecosystem.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 6th - Tylosaurus

6th - Tylosaurus

Tylosaurus was a species of Mosasaur. It was enormous, reaching more than 50 feet (15m) in length.

The tylosaurus was a meat eater with a very diverse diet. Stomach remains show signs of fish, sharks, smaller mosasaurs, plesiosaurs, and even some flightless birds. They lived during the late Cretaceous in the seas that covered North America, where they sat firmly atop the marine food chain for several million years.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 7th - Nothosaurus

7th - Nothosaurus

Nothosaurus, only about 13 feet (4m) long, were aggressive hunters. They were armed with a mouth full of sharp, outward-pointing teeth, suggesting a diet of squid and fish. Nothosaurus is thought to have mainly been an ambush predator, using its sleek reptilian figure to sneak up on prey and take it by surprise.

It’s believed that Nothosaurs were related to pliosaurs, another variety of deep sea predators. Fossil evidence suggests that they lived during the Triassic period over 200 million years ago.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 8th - Thalassomedon

8th - Thalassomedon

Thalassomedon was a species of Pliosaur whose name translates from Greek to “sea lord” – and for good reason. They were massive predators, reaching lengths of up to 40 feet (12m).Its flippers were nearly 7 feet (2m) long, allowing it to swim the depths with deadly efficiency. 

Its reign as a top predator lasted through the late Cretaceous period, finally coming to an end when the sea saw new and larger predators like the Mosasaur.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 9th - Dakosaurus

9th - Dakosaurus

Dakosaurus was first discovered in Germany and, with its odd reptilian-yet-fishy body, was one of the top predators in the sea during the Jurassic period.

Fossil remains have been found across a very widespread distribution, turning up everywhere from England to Russia to Argentina. Though it is commonly compared to modern crocs, Dakosaurus could reach a length of 16 feet (5m). Its unique teeth have led scientists to consider it an apex predator during its reign of terror.Source

What do jellyfish eat?

Top of prehistoric sea monsters. 10th - Shastasaurus

 10th - Shastasaurus

The ichthyosaurs were marine predators that looked like modern dolphins, and could reach a massive size during the Triassic period over 200 million years ago.

Shastasaurus, the largest marine reptile species ever found, was a variety of ichthyosaur that could grow to over 65 feet (20m), much longer than most other predators. But one of the largest creatures to ever swim the the sea wasn’t exactly a fearsome predator; Shastasaurus was a specialized suction feeder, eating mainly fish. Source

What do jellyfish eat?

A new Dark Age?

We need to do more to prevent the world descending into a new Dark Age We need to do more to prevent the world descending into a new Dark Age as a result of climate change, argues Professor Tim Flannery.

In 2006 James Lovelock published a book that bluntly laid before us the consequences of the carbon imbalance. The Revenge of Gaia argues Gaia's climate system is far more sensitive to greenhouse gas pollution than we imagine, and the system is already trapped in a vicious circle of positive feedback.

What do jellyfish eat?

Although there is still time to avert a catastrophe, Lovelock believes humans lack the foresight, wisdom and political energy required to do so. Instead, he predicts, before the 21st century is out our global civilisation will have collapsed and a new Dark Age will have dawned, wherein a few survivors will cling to the few remaining habitable regions, such as Greenland and the Antarctic Peninsula.

How probable is it that this bleak vision will come to pass? New scientific data means that in 2009 we are better placed than ever to determine the scale of the threat and its imminence.

The northern fridge

The sea ice that covers the Arctic Ocean is an ancient feature of our planet. It has glistened brightly into space for at least three million years.

The northern ice acts as a refrigerator that cools the entire planet. During the summer, the sun's rays beat down upon it 24 hours a day, but because the ice is bright, 90 per cent of that energy is deflected back into space.

By 2005 the Arctic ice cap had been melting at a rate of around eight per cent per decade for thirty years. At that rate, it would have taken until 2100 or thereabouts for the ice cap to disappear altogether.

But in the summer of 2005, a dramatic change occurred. The rate of melt accelerated, so that around four times as much ice melted as compared with previous summers.

These changes in the Arctic have left many scientists worried the region is already in the grip of an irreversible transition. During the winter months, the Arctic is now warming four times faster than the global average, while the existing temperature increase year-round already exceeds two degrees Celsius.

What will happen during that first iceless summer? Most likely, not much at all, for it will take several summers' worth of energy to warm the surface of the Arctic sea to a point where dangerous changes are generated further south. But each year thereafter, the ocean at the top of the world will warm inexorably, and the temperature gradient that controls climatic zones across the northern hemisphere will shift.

If we look back to the last time in Earth's history when such a great warming occurred — 55 million years ago — we see an ominously different world.

Back then, lemurs sported in the rainforests of Greenland, while the tropics were covered in a spiny, thin and alien-looking cover of vegetation, which is today entirely extinct. No one knows how quickly the world's climate altered back then, but one cannot help but fear what a similar scale of change might mean for humanity today.

A dying sea

New ramifications of rapid warming are continually being discovered. In 2006 scientists realised that the sea can die as a result of massive global warming. Indeed, it has done so several times during Earth's history, and when it does, it takes most life on land with it.

The most devastating example of oceanic death occurred around 250 million years ago, when 95 per cent of all life perished.

Geologists studying rocks in Western Australia discovered traces of the unique lipids (fatty molecules) made by strange kinds of bacteria known as purple bacteria and green sulphur bacteria.

These bacteria only thrive in waters that are well lit by the sun, yet are low in oxygen and high in hydrogen sulphide. Such conditions exist only in very restricted and unusual environments today, such as the 'jellyfish lakes' of Palau. Yet the story preserved in the rocks reveals that most, if not all, of Earth's oceans resembled this environment 250 million years ago.

Answers in the ice-core
How much time do we have to prove Lovelock wrong? On 31 March 2008, Dr James Hansen and eight of his colleagues provided a new, alarming, though still partial, answer to this question.

They looked back over the increasingly complete ice-core record, which documents the last three-quarters of a million years of Earth's climatic history, and tried to determine how much warming a given amount of atmospheric CO2 pollution would produce, and how long it would take to produce it.

Their most alarming discovery was that, when viewed over the long term, Earth's climate system is about twice as sensitive to CO2 pollution as is shown on the Intergovernmental Panel on Climate Change's century-long projections.

This implies that there is already enough greenhouse gas pollution in the atmosphere to cause two degrees Celsius of warming, bringing about conditions not seen on Earth for two to three million years and constituting, according to the authors, "a degree of warming that would surely yield 'dangerous' climate impacts".

Fortunately for us, some, perhaps half, of that warming is currently masked by other pollutants, known collectively as the agents of global dimming, which reflect sunlight into space, thus cooling Earth.

Today, China, India and other rapidly industrialising economies are releasing these pollutants in ever-increasing quantities. Yet because of their effect on visibility and their serious impact on human health, there's good reason to believe that in the near future such nations will move to curb their release.

Close to the point of no return

In their landmark paper, Hansen and his colleagues make a useful distinction between climatic "tipping points" and "the point of no return."

The climatic tipping point is the point at which the greenhouse-gas concentration reaches a level sufficient to cause catastrophic climate change. The point of no return is reached when that concentration of greenhouse gas has been in place sufficiently long to give rise to an irreversible process.

Humanity is now suspended between a tipping point and a point of no return. We still have a few years before we reach the point of no return, but there is not a second to waste. This is our greatest challenge: to draw the pollution out of the air and save ourselves from Lovelock's new Dark Age. Source

Killer jellyfish

A jellyfish with a deadly sting has been bred in captivity for the first time by Australian scientists, opening up the possibility of developing an antivenom.

The tiny box jellyfish, with a bell just 12 millimetres long, is responsible for Irukandji syndrome, a potentially fatal condition that attacks the central nervous system.

Researchers Heather Walling and Lisa-ann Gershwin from the CRC Reef Research Centre at James Cook University (JCU) in Townville announced their results this week.

The jellyfish, Carukia barnesi, had gone through a planktonic stage and were now attached to rocks on the floor of an aquarium at the Marine Aquaculture Research Facility Unit at JCU.

Irukandji jellyfish are found around the northern coast of Australia. And the species grown in captivity is one of nine to cause Irukandji syndrome, which killed two tourists in Australia in 2002.

Gershwin said Irunkandji syndrome began with a mild sting, like a mosquito bite. Within an hour, victims experienced severe lower back pain, shooting pains all over the body, cramping, nausea, vomiting, profuse sweating and coughing.

Depending on the species, loss of motor control and paralysis could follow, with some victims eventually dying of brain haemorrhages or heart failure.

Gershwin, who also works at the Australian Institute of Marine Science, said the deadly syndrome could be responsible for many more deaths not diagnosed at first.

"The significance of being able to breed these little guys is huge," said Gershwin.

What do jellyfish eat?

Breeding the jellyfish was the first stage to developing an antivenom, she said, which required between 10,000 and 1,000,000 jellyfish.

She said developing an antivenom would involve extracting the toxin from the stinging cells, chopping the molecule up into "different bits" and testing different concentrations of those bits in animals.

Captive breeding also meant more jellyfish toxins were available for scientists to study potential pharmaceutical benefits, and could also allow for rapid diagnostic techniques for Irukandji stings.

"Because of the incredible potency of the toxins, the likelihood of being able to harvest useful chemicals is very high," said Gershwin.

"Researchers require reliable supplies of the jellyfish, which Mother Nature doesn't always provide. People are poised ready to pounce on the next available specimens."

Gershwin said she wasn't sure what defining factor had allowed them to breed the jellyfish successfully; she said it was "mostly luck". Many researchers had been trying to breed the jellyfish since the 2002 deaths.

Clues to the nervous system

Dr Michael Corkeron from Townsville Hospital, a doctor who is developing a new treatment for the syndrome, said that a better understanding of its physiology would most likely lead to better ways to treat it.

Anything that affected the central nervous system like that might also help researchers understand how the nervous system worked, he said.

And perhaps scientists would find out whether the toxin held clues to mechanisms that could block particular effects on the system, Corkeron told ABC Science Online.

"You have to wonder if something so powerful holds some pharmaceutical benefits," he said. Source

A ray of hope for coral reefs

Australian researchers have shown how some reef-building corals might protect themselves against the double threat of global warming and ozone depletion.

Publishing in this week's issue of Nature, Dr Anya Salih and colleagues at the University of Sydney have found that certain varieties of corals use fluorescence to take the sting out of intense UV light, which otherwise acts together with warmer water temperatures to cause coral bleaching.

Acropora nobilis: Corals depend on microscopic algae which live in symbiosis inside the coral tissues, providing a steady supply of sugars for the host coral. While the algae require light, too much of it shuts photosynthesis down - a process called photoinhibition. When this happens, the coral expels its damaged symbiont and dies.

It had been observed for some time that corals fluoresced green when blue light was shone on them - but no one knew why. Although these corals had a compound similar to GFP (green fluorescent protein) found in luminescent jellyfish, they did not glow in the dark like the jellyfish do. So what was the function of the fluorescent pigment?

What do jellyfish eat?

Salih and team postulated that the fluorescence played a role in protecting algae from damaging UV radiation and so set out to test the hypothesis.

Pocillopora damicornis "Our results show that in well-lit environments these fluorescent pigments act as 'sunscreens', protecting coral symbionts from photoinhibition by transforming excess light to wavelengths which are not absorbed by the algae and therefore will not damage them," say the researchers.

The research team transplanted corals in the laboratory and observed them under different light intensities and water temperatures. They found that the algae in fluorescent corals were able to continue photosynthesising while those in non-fluorescent corals shut down photosynthesis.

Their laboratory findings were confirmed by field work that showed that in massive bleaching events, fluorescent corals were damaged less than their non-fluorescent neighbours.

"This has important implications in the light of current climatic changes," say the researhcers. "Many species have fluorescent morphs - will these become predominant as temperatures and ultraviolet radiation increase? If so, they may offer the reef environment a partial buffer against global climate change."

"We do not suggest that we should be complacent about global warming or ozone depletion, but our studies may provide a ray of hope for the reef ecosystem."

The researchers are currently funded by an Australian Research Council SPIRT Fellowship (Stragetic Partnerships in Industry, Research and Technology) award.

Sunfish seekers

While southern Australia shivers through winter one of our strangest marine neighbours heads north like any other sensible sun seeker. And Bali is one of the few places in the world where you can swim with the elusive sunfish.

When marine biologists Rob Harcourt and Matthew Kertesz saw the giant dorsal fin poking out of the water immediately ahead of their tiny boat, they thought the worst. It was not unusual to spot a big shark in Jervis Bay, south of Sydney, an area famed for its rich ocean life and stunning clear water. But on closer inspection, Harcourt felt his heart beat faster with excitement as he realised that a very different kind of creature loomed below him in the water.

As it wheeled over onto its side, the animal revealed itself to be a giant ocean sunfish, normally found hundreds of kilometres out to sea, which had somehow meandered into the shallow waters off the coast.

The two marine specialists realised what a rare treat stumbling across the fish was. They lost no time donning flippers and masks, and leapt into the 40 metre deep water with a camera.

Up close, the animal was breathtaking. This was just a little one: about three metres across, but Harcourt knew these ocean giants could reach over four metres in length and weigh up to 2000 kilograms.

The huge eye, the size of a fist and not at all afraid, loomed close as Harcourt took in the body shape, possibly one of the strangest in the already strange world of fishes.

The head was enormous: in fact, the animal appeared to be all head, with a tail fin running down the back of the 'neck'. Emerging from this head/body were the fins. Lacking most of the fins a normal fish has, sunfish have just two: giant couch-sized appendages protruding from top and bottom of the body. In front of the huge doleful eyes were the lips, as large and luscious as Mick Jagger's.

The amazing sunfish

What do jellyfish eat?

The sunfish is the largest and most fertile bony fish in the world. Some sharks (such as the whale shark and great white) can grow larger, but these are cartilaginous fish, rather than bony fish. Sunfish can produce massive numbers of eggs: one female caught off Florida was carrying 300 million eggs. This makes the cane toad look quite modest, producing a mere 60,000 eggs per clutch.

Sunfish tend to lie on their side close to the surface of the ocean, appearing to bask in the warmth of the sun, say researchers at the Large Pelagic Research Lab at the University of New Hampshire. They may be 'thermally recharging' after diving to depths where their bodies have been significantly cooled by the deep water.

Although a rare sight near the coast of Australia, researchers say sunfish have been seen off Perth and at Ningaloo Reef, and also in the harbours of Darwin and Sydney. They inhabit all the main oceans of the world, both tropical and temperate.

There are also anecdotal sightings of sunfish made by the general public. Responding to a Sydney Morning Herald story about the Jervis Bay sunfish sighting, readers variously reported seeing sunfish at Botany Bay and Wollongong, and in New Zealand at the Three Kings (northern New Zealand) and Palm Beach (west of Auckland).

The group Molidae includes four species of sunfish: Ranzania laevis (slender mola), Masterus lanceolutus (sharptailed mola), Mola mola (common mola), and Mola ramsayi (Southern Ocean Sunfish). Sunfish are frequently called 'mola' even though only two of the four species are in this genus. ('Mola' in Latin means "millstone" and describes the ocean sunfish's somewhat circular shape.)

Up close and personal

Anyone who spots a sunfish at sea is pretty lucky. Normally, the only way to get a close-up look at a real sunfish is to wait until an injured or dead individual washes up on a beach. But there is at least one place in the world where you are almost guaranteed to see a sunfish and even dive with one of these marvels of nature.

Near several tiny coral-fringed islands off the east coast of Bali, sunfish congregate each year from August through to October. Mysteriously, the normally ocean-loving fish move towards the coast at this time of the year to feed and live in waters as shallow as 25 metres, making it one of the best places in the world to see them.

Since arriving in Bali from Perth eight years ago Jonathan Cross, who runs dive company Blue Season Bali, has led hundreds of sunfish dives, but still finds it fascinating.

He'll typically see up to 20 sunfish each day across several dive sites: "They are amazing things ... very difficult to describe. You can go right up to them and they've got this deep, black eye set right back in their frame. They look so prehistoric, they seem to have been around for such a long time. "

"They swim around and may scoot away if you scare them or blow bubbles at them but you can get as close as 1 metre from them. They can be very curious...When they are coming towards you, they look quite thin, but then when they turn side out, they are just massive."

There are a number of theories as to why sunfish flock to Bali each year. One reason may be to get parasites removed by the cleaner fish which abound on the reef. The huge surface area of the sunfish is a magnet for parasites, and up to 40 different species of isopods, worms and molluscs have been found picnicking off one fish.

The area also experiences a peculiar upwelling of cold, deep, water from August through to October. This nutrient-rich water is a rich food supply for tiny marine animals which may attract sunfish.

Travelling to Bali may be the best way to see sunfish up close, but where they spend the rest of their time remains something of a mystery.


Mola mystery

In America, researchers have been devising ingenious ways of following the normally elusive sunfish to try and get a handle on even the most basic information about their biology, development and movements.

Inga Potter, a researcher with the Large Pelagic Research Laboratory at the University of New Hampshire, is one of only a handful of researchers who focus on sunfish. Her group has attached satellite tags to sunfish off the north-east coast of the United States, and tracked their movements over summer. But even attaching tags is no easy matter. Smaller species such as turtles can be caught and hauled aboard to be tagged, but not a 2000 kilogram sunfish. The only way is to jump into the water with the fish and physically attach the tag, all the while hoping you don't encounter any unpleasant visitors!

Potter's tagging studies are beginning to reveal that sunfish travel vast distances: one fish tagged off the coast of New England travelled 3000 kilometres in 130 days, eventually ending up in the Gulf of Mexico before returning north. So why the big trip?

Potter suggests that sunfish leave the north east to begin their trek southwards in response to cooling sea surface temperatures. As the sea temperature declines, plankton numbers go down, and so in turn do the jellyfish which feed on plankton. Jellyfish are the main food source for sunfish, so once jellyfish numbers drop, sunfish beat a hasty retreat south in search of more tucker.

Sunfish may also be moving south in order to spawn in the warm southerly waters, as both tuna and swordfish do. "I would love to know more about mola spawning and reproduction," says Potter, "but I am not sure how that question will ever get answered, certainly not in our present study!"

The satellite tagging has provided information not just about the distances sunfish travel, but also about the depths they go to, and how they move about vertically within the water column. It also answers a question which Potter had been puzzling about: how do the southward-travelling sunfish tackle the rapidly northward moving waters of the Gulf Stream which lies directly in their path? The satellite tracking data revealed that when sunfish encounter the current, they actively swim under it, diving to depths of up to 750 metres.


A life in danger

As researchers struggle to learn more about sunfish, they face a vulnerable future. Although not intentionally caught for human consumption (except in Japan), thousands of sunfish are killed each year as part of the bycatch of other fisheries. According to Potter's research group the common sunfish M. mola makes up a large portion of the bycatch of the Pacific and Mediterranean bluefin long line fishery. A massive 70 to 90 per cent of the total swordfish driftnet catch was made up of the common sunfish between 1992 and 1994, and in the Pacific, ocean sunfish make up a quarter of the total haul of swordfish driftnet fisheries.

In Australia, sunfish are also killed as bycatch in the tuna and billfish fishery, according to records from the Commonwealth Pelagic Longline Fishery Data. Yet virtually no research has been done on the sunfish which live around the coasts of Australia. Nothing is known of how far and where they travel, or when and where they breed. Until a more focused research program appears, we'll have to rely on the occasional lucky encounter to learn more about this spectacular animal.

Credits
Thanks to Jonathan Cross, Director of Blue Season Bali for the use of photo and video images of sunfish and for sharing his experience of diving with them. Thanks also to Rob Harcourt from Macquarie University for photo images of sunfish and to Ingrid Potter from the University of New Hampshire for providing information about her research.
 Source

Jellyfish Reproduction

What do jellyfish eat?

The jellyfish is one of the most mesmerizing creatures of the marine land. They have a fascinating aspect to their life cycle, which is their process of reproduction. The process of reproduction in a jellyfish involves a number of different stages and the jellyfish passes through a number of different forms before it develops into the easily recognizable adult form in the last stage of the reproduction cycle. On the other hand, the different stages of reproduction in a jellyfish involve both the sexual and the asexual from of reproduction. Let's look at the reproduction cycle of the jellyfish to understand this fascinating process. 

Fertilization

jellyfish do not have any specialized bodily system for reproduction. The male jellyfish releases its sperm in the water. The female carries her eggs in her mouth or stomach. When the sperm that are released in the water come in contact with the female's eggs, they get fertilized. In the embryonic stage, these fertilized eggs are stored in brooding pouches along the oral arms of the female or in her stomach. 

Planula Larvae

After the embryonic stage is over, the larvae get transformed into tiny planulae that are free swimming and they detach themselves from their mother's body. At this stage, the jellyfish looks an oval shape and has tiny hair along its body that act like multiple oars to facilitate movement. However, these are not very effective, and the planulae float for a few days in the tides and currents of the water. At this stage, they start sinking towards the deep end of the ocean until they attach themselves to a hard surface and the next stage in their reproduction cycle begins. 

Polyps

Once the planula has found a hard surface, it attaches itself to it at its base. On the other end of the planula is its mouth which is surrounded by a few tentacles which help in procuring food and transport it to the planula's mouth. At this stage, this planula becomes a polyp and begins the most sessile stage of its life. It remains attached to the surface, and over time a new polyp gets formed from the trunk of the first polyp. This process is repeated innumerable times, until an entire colony of polyps is formed. The polyps of this colony are all connected to each other with small feeding tubes. This ensures that every polyp receives adequate nutrition irrespective of its place in the colony. This stage of jellyfish reproduction can last for years and the polyp colony can grow up to a tremendous size. 

Ephyra

When conditions are right, this colony of polyps begins to transform itself. Horizontal grooves appear on the outside of the colony. The topmost groove, which matures the fastest, then detaches itself from the colony and becomes a free swimming tiny jellyfish known as ephyra. 

Medusa

This is the last stage of the jellyfish reproduction cycle and the most recognized. The ephyra stage gives to the medusa stage where the tiny jellyfish grows into an adult and has a fully formed body and its distinct shape. Source

Do jellyfish have brains?

What do jellyfish eat?

Jellyfish is a creature of our fascination because it is not easily visible and resides in deeper parts of the ocean and due to the fluorescent color which is emitted out of jellyfish, it is an attractive creature for us. This is just the tip of the iceberg when you’re speaking about the unusualness of jellyfish as compared to the other animals on land or even the marine creatures. Jellyfish is entirely different in the bodily structure as well as from a scientific point of view.

If you look into the bodily structure of jellyfish you would realize that, the nervous system of the jellyfish is entirely different and this brings us to the question do jellyfish have brains? If they have a nervous system, people might think that they have a brain as well but this is not true.

No, jellyfish do not have brains. You might be thinking that we have mentioned that jellyfish has a nervous system but how is that nervous system can control the jellyfish if it does not have a brain. This is where jellyfish is entirely different from the other creatures on land as well as in sea.

If you’re looking into the anatomy of the body of other animals you would find out that it is in symmetry. That is there is some similar organs on the left side of the body of the animals and on the right side of the body of the animals but there is no such similarity in jellyfish.

If you look into the body of jellyfish you would understand that bilaterally they are not similar at all. That is why, the way in which the body of the jellyfish operates is also different than other animals.Source

What Do JellyFish Eat?

What do jellyfish eat?

Jellyfish have existed on planet earth even before the age of dinosaurs. There are more than 200 different species of jellyfish inhabiting the oceans. Some of them are even found in fresh water. Jellyfish are found in all oceans, at varying temperatures and depths.

Jellyfish derive their name from their jelly like main body. The bell-shaped jellyfish body has long tentacles attached to it. The lack of skeletal system gives them an unusual appearance, as documented in our jellyfish pictures. The brain-less jellyfish is amusing to watch.

Jellyfish are carnivorous and ravenous eaters. The mouth of the jellyfish is located underneath the bell-shaped body. Its simple digestive system consists of a gastro vascular cavity attached to the oral opening, which does the function of the stomach.

The same opening under the body that serves as its mouth is used for releasing excreta from the body. The food entering the opening is digested in the cavity attached to it. The waste matter generated is expelled through the same opening.

Jellyfish normally eats whatever their long tentacles catch while drifting in the ocean currents. A few species of jellyfish like the box jellyfish are good swimmers and chase their prey. The main food sources of jellyfish are smaller fishes, eggs and larvae of sea creatures and zooplankton. The larger species of jellyfish eat crustaceans and other jellyfish.

The tentacles are the main devices to catch prey for jellyfish. These tentacles have thousands of cnidocytes with stinging capsules or nematocysts containing venom. Even though these creatures are brainless, their nervous system is highly developed. When the tentacles touch a potential prey, the cnidocytes are activated immediately. They shoot nematocysts at the prey, which attach itself to the skin of the prey. The venom present in these nematocysts is released, which in turn stuns the prey.

The shocked prey is caught by the arms surrounding the oral opening and brought to the mouth. The food is digested immediately in the chamber attached to the opening and nutrients absorbed by the body. The waste is discharged through the same opening.

Many species of jellyfish are passive hunters and wait for their prey to come to them. They have sticky tentacles and drift along the currents waiting for a prey to get trapped in the tentacles. They eat mostly zooplankton, eggs and larvae of other marine creatures and crustaceans.

Some species of jellyfish are aggressive hunters and they are equipped with potent venom in their tentacles. This venom when ingested in the prey either paralyzes or kills it. This group of jellyfish preys on smaller fishes, crustaceans and even other jellyfishes. Some jellyfish is known to eat other jellies as large as themselves. Learn more about poisonous jellyfish.

Some species of jellyfish like the spotted jellyfish are filter feeders. They consume large quantities of seawater and absorb the food present in it. The spotted jellyfish is known to cause havoc in the marine life by consuming large quantities of useful zooplankton. They are also known to devour eggs and larvae of commercially important marine animals like shrimps and oysters. Source

Alien jellyfish hitch a ride on ships

Exotic jellyfish from Japan and Europe are stowing away on ships and thumbing a free ride to Australia, new research suggests.

According to a US and Australian report in today's Proceedings of the National Academy of Sciences, moon jellyfish are hitchhiking around the globe in ships' ballast waters and hulls.

And they may have been doing so for more than 500 years when international shipping and trade began in earnest.

While moon jellyfish are found in many parts of the world, including Australia, researchers from the University of California, Davis and the University of New South Wales have found strong evidence that most are not indigenous to the area they live in.

The finding adds to data from recent surveys suggesting that around 23% of all marine species in international harbours are not indigenous, a situation scientists fear could displace local marine species, threaten ecosystems and cause billions of dollars in damage and preventive control.

Around 3000 species of marine organisms travel the world in ships' ballast water each day.

Researchers used computer simulations of ocean currents and water temperatures and examined the DNA of moon jellyfish found in Japan, California, western Europe and the east and west coastlines of Australia to determine their origin.

"We simulated natural dispersion including all sorts of effects such as tidal currents and eddies in the ocean," says Associate Professor Matthew England, an Australian oceanographer who worked on the study.

"And we demonstrated that you could never get a jellyfish, say, from Japan right down to Australia in this way. It had to be the ships facilitating their dispersion."

He says while moon jellyfish are benign, and don't sting people, their migratory behaviour is still a concern.

"We're increasingly finding introduced species in new waters," England says.

"While we don't think this particular jellyfish will change the ecosystem or alter the food chain too dramatically, it's alarming if you think about a toxic species [of marine life] being introduced in this way. That could have significant consequences." Source

Fin study gives hint on hind leg evolution

A new study of fin development in fish has shed light on the evolution of hind leg muscles in land-dwelling animals.

Developmental biologist Professor Peter Currie from Monash University and colleagues report their findings online in the open access journal PLOS Biology.

"Sadly it's a fact of evolution that we are just modified fish," says Currie.

But, he says, the question is how did the tiny fins of fish develop into the powerful legs of land-dwelling tetrapods.

"The biggest gap in our knowledge is how we go from these puny little pelvic fins that seem to do almost nothing in fish to these huge hind limbs that support our weight on land," says Currie.

But he says while there is some evidence about how the skeleton evolved for weight-bearing limbs muscles, they are not preserved in the fossil record.

"There is absolutely no information about how the muscles that drive the locomotion ... came into being," says Currie

Stepping stone
To gain insights into the evolution of these muscles, Currie and colleagues analysed the development of pelvic fin muscle in two living species of 'primitive' cartilaginous fish and three living species of bony fish.

"The fish that we've been looking at are sitting evolutionarily at important branches of the tree of life," says Currie.

At one end of the spectrum is the bamboo shark and the so-called elephant shark, which is the most primitive fish with paired fins.

The researchers also looked at the zebra fish and our "nearest fishy cousin", the Australian lungfish, along with a North American paddlefish, which, in evolutionary terms, sits halfway between the sharks and the other bony fishes.

Currie and colleagues found that bony fish have a different mechanism of pelvic fin muscle formation than that found in the cartilaginous fish.

This mechanism is an important stepping stone for the evolution of land-dwelling animals, say the researchers.

"We had to go from this halfway house mode of making muscles in the pelvic fin to the mode that we use in order to develop proper hind-limb muscles," says Currie.

"Making more muscle and bigger muscle and positioning those muscles appropriately to make the big hind leg muscles was a very import step for the movement onto land. That's the major evolutionary thrust of the paper."

Fluourescent fish

One experiment carried out by Currie and team involved tracking the development of pelvic fin muscles in zebra fish by tagging the muscle cells with fluorescent jellyfish protein.

The researchers genetically modified one set of 'donor' embryos with red fluorescent jellyfish genes and transplanted their muscle progenitor cells into 'recipient' embryos with green fluorescent jellyfish genes.

They then watched how the red donor cells grew in the recipient.

"This is a technique that's been used very successfully in other developmental systems but so far hasn't been applied to fish because they are very small embryos," says Currie.

Interestingly, he says, pectoral fins seems to have evolved more rapidly than the pelvic fins, with the mechanism of their development in fish being similar to that used in the legs of land dwelling animals. Source

Toxic shock from stinger family

Up to eight species of small, almost invisible box jellyfish cause Irukandji Syndrome - and there is no antivenom for their potentially fatal stings.

Dr Peter Fenner, Associate Professor at the James Cook University School of Medicine, and Mr John Hadok, of the Emergency Department at Mackay Base Hospital, have documented the first reported death from Irukandji Syndrome in the in The Medical Journal of Australia.

"More than 100 people are likely to be stung and visit hospital this summer. Tragically this year, for the first time, there were two fatalities from Irukandji Syndrome in North Queensland", said Dr Fenner.

Two middle-aged men were killed by jellyfish stings earlier this year, in separate incidents near Port Douglas and in the Whitsunday Islands.

Dr Fenner believes that the jellyfish responsible for the deaths is an undescribed species of Irukandji that lives around the outer reefs and the Whitsunday Islands of the Great Barrier Reef.

The Irukandji box jellyfish, or cubozoans, are related to the deadly large box jellyfish or stinger Chironex fleckeri, which has killed more than 60 people in Australia.

Irukandji jellyfish have nematocysts, or stinging cells, on the body as well as the tentacles. When touched, these cells fire a tiny shaft into the victim's skin, that delivers the potent venom which causes Irukandji Syndrome.

The basic symptoms develop 30 minutes after being stung. They include severe low back pain; excruciating muscle cramps in arms, legs, belly and chest; sweating, nausea, anxiety, restlessness, vomiting, and headache.

The fatal cases developed such severe hypertension, or high blood pressure, that they died from brain haemorrhages, one within 30 hours after being stung.

"The Irukandji venom causes nerve endings to release large amounts of noradrenaline, the chemical that produces the "fight-or-flight" reaction", says Dr Fenner.

"The smaller blood vessels contract, which leads to the hypertension or high blood pressure, as blood is not able to squeeze through. There is no first-aid treatment for the hypertension."

"The venom is also a direct cardiac toxin, turning the heart into a floppy bag that is not able to pump blood effectively. This leads to pulmonary oedema, or fluid building up in the lungs", he says.

Irukandji Syndrome is most prevalent between early December to mid-February, along the tropical coast from Broome in WA to Rockhampton in Queensland.

Dr Fenner cautions that the development of an effective Irukandji antivenom is not presently possible, especially when the lifecycle of the species is unknown.

Dr Jamie Seymour, Senior Lecturer at the James Cook University School of Tropical Biology in Cairns, says that the syndrome was originally attributed to one species of box jellyfish named Irukandji, or Carukia barnesi.

"In the last few years, as symptoms become better defined, it appeared that people stung in Mackay were showing different symptoms from those stung in Cairns. It led us to wonder if maybe different species are involved."

"We're able to identify cubozoans by taking skin scrapings from people who have been stung, as the nematocysts stay in the skin. Each species has nematocysts of a particular shape", said Dr Seymour.

"There are nematocysts from 7 or 8 skin scrapings that I have never seen before and cannot identify. One of these samples came from the man killed at Whitsunday Islands."

Dr Seymour and other researchers are assisting Dr Fenner by netting 1800 specimens of Carukia barnesi from around Cairns for the Australian Venom Research Unit. Source

Fossilised iceblocks shed light on early life

The discovery of blocks of gravel which sank to the bottom of the sea trapped in ancient icebergs has sparked a new understanding of a bizarre group of creatures.

The research published today in the Australian Journal of Earth Sciences, has also forced a rethink of the conditions that existed more than 500 million years ago.

Associate Professor Victor Gostin and colleagues at the University of Adelaide found evidence of ancient icebergs mixed in with volcanic rocks which were spewed out when an asteroid hit the earth between 635-542 million years ago.

The 4.7-kilometre asteroid left a 90-kilometre crater in what is now Lake Acraman in the Gawler Ranges of South Australia.

Gostin, who first discovered rocky traces of the asteroid 'ejecta' almost 30 years ago, says the asteroid impact occurred during a period of extreme cold.

This contradicts previous ideas which suggest the impact of the asteroid actually precipitated a period of glaciations, Gostin says.

He says evidence of the ancient icebergs is embedded in the fine grained shale found several hundred km from Lake Acraman.

"Icebergs carry coarse debris, boulders and grains," says Gostin. "As the iceberg melts it is dragged to the bottom by the weight of the debris, then the ice melts and the surrounding mud eventually buries the debris, creating this sort of fossilised iceblock.

"So when you find coarse boulders embedded in fine deposits, something must have rafted it there - in this case, an iceberg."

'Double whammy'

In a commentary to be published in the The Australian Geologist, Professor Malcolm Walter of the University of New South Wales says the research resolves issues around the timing and record of the glaciations, the impact and the rise of the Ediacaran biota.

He describes the effect of the icy climate and asteroid impact as a "double whammy" that paradoxically led to the "flourishing of exotic plankton and the first macroscopic animals".

"Did the Acraman impact and coincidentally coeval glaciation help trigger one of the great biological revolutions in earth history? Time will tell," writes Walter.

The Ediacaran fauna, which were the first large complex life forms to appear. They resembled do jellyfish, sponges, marine worms, plus other organisms whose body plan resembles nothing alive today.

Gostin is keen to explore other glacial deposits that formed around the same time in other parts of the world to see if there is further evidence of the asteroid's impact on the microscopic creatures at that time.

Anti-venom researchers

Australia's leading anti-venom research group may close its doors at the end of June following the withdrawal of funding from the Victorian State Government.

The Australian Venom Research Unit has developed anti-venoms to treat people bitten by the country's many poisonous animals, insects and fish for the last seven years.

More than 3,500 bite and sting victims are treated in hospitals around the country each year for potentially deadly venom-related conditions.

According to a report in The Age newspaper today, the unit's annual funding of $100,000 from the Victorian State Government, which pays for the salaries of the unit's director and deputy director, will not be renewed.

The government has told the unit's director, Dr Ken Winkel, that their funding should be the responsibility of the Federal Government.

"This is not just about Australia, it has international implications", Dr Winkel told The Age. "If this unit disappears, it will be a symbolic as well as a practical loss. People are dying every year in Australia and thousands more are dying overseas."

Last week a woman was in a critical condition after being stung by a jellyfish in Western Australia.

"This illustrates that the problems are not solved," Dr Winkel told The Age. "We still have challenges every day. There's still so much to learn about Australia's venomous creatures and managing the effects of their toxins."

A spokesman for the Victorian Department of Human Services said the unit had been given $770,000 in funding over the last seven years.

"We recognise that the unit does important work, but we're not the only beneficiary and we should not carry the financial burden," the spokesman told The Age. "We have approached the Commonwealth and they have been receptive to our approaches and to the unit's plight, but they have not made a commitment as yet."

Australia has provided international leadership in anti-venom research and is the only country to produce anti-venoms for sea snakes, sea wasp, blue-ringed octopus and stone fish.

The venom unit provides a 24-hour advisory service to medical practitioners on the management of bites and stings, investigates the impact of envenomations on public health, and researches new anti-venoms. Source