Tag: Biology

World’s Heaviest Bony Fish Identified And Correctly Named

Last December 6 in Tokyo, the world’s heaviest bony fish ever caught – weighing a whopping 2,300 kilogrammes – has been identified and correctly named by Japanese experts.

The fish is a Mola alexandrini bump-head sunfish, and not a member of the more commonly known Mola mola ocean sunfish species as originally thought, according to researchers from Hiroshima University.

Bony fish have skeletons made of bone rather than cartilage, as is the case for sharks or rays.

In the study, published in the journal Ichthyological Research, researchers led by Etsuro Sawai referred to more than one thousand documents and specimens from around the world – some of which date back 500 years.

Their aim was to clarify the scientific names for the species of the genus Mola in fish.




They also solved a case of mistaken identity. The Guinness World Records lists the world’s heaviest bony fish as Mola mola, researchers said.

However, Sawai’s team found a female Mola alexandrini specimen of 2,300 kilogramme and 2.72 meter caught off the Japanese coast in 1996 as the heaviest bony fish ever recorded.

Sawai’s team re-identified it as actually being a Mola alexandrini based on its characteristic head bump, chin bump and rounded clavus although this specimen was identified Mola mola until now.

Ocean sunfishes count among the world’s largest bony fish, and have for centuries attracted interest from seafarers because of their impressive size and shape, researchers said.

Specimens can measure up to three meters (total length), and many weighing more than two thousand kilogrammes have been caught.

Instead of a caudal fin, sunfish have a broad rudder-like lobe called a clavus, they said.

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Which Came First, The Lizard Or The Egg?

Evolution has been caught in the act, according to scientists who are decoding how a species of Australian lizard is abandoning egg-laying in favor of live birth.

Along the warm coastal lowlands of New South Wales, the yellow-bellied three-toed skink lays eggs to reproduce.

But individuals of the same species living in the state’s higher, colder mountains are almost all giving birth to live young.

Only two other modern reptiles—another skink species and a European lizard—use both types of reproduction.

Evolutionary records shows that nearly a hundred reptile lineages have independently made the transition from egg-laying to live birth in the past, and today about 20 percent of all living snakes and lizards give birth to live young only.

But modern reptiles that have live young provide only a single snapshot on a long evolutionary time line, said study co-author James Stewart, a biologist at East Tennessee State University.




The dual behavior of the yellow-bellied three-toed skink therefore offers scientists a rare opportunity.

One of the mysteries of how reptiles switch from eggs to live babies is how the young get their nourishment before birth.

In mammals a highly specialized placenta connects the fetus to the uterus wall, allowing the baby to take up oxygen and nutrients from the mother’s blood and pass back waste.

In egg-laying species, the embryo gets nourishment from the yolk, but calcium absorbed from the porous shell is also an important nutrient source.

Some fish and reptiles, meanwhile, use a mix of both birthing styles. The mother forms eggs, but then retains them inside her body until the very last stages of embryonic development.

The shells of these eggs thin dramatically so that the embryos can breathe, until live babies are born covered with only thin membranes—all that remains of the shells.

This adaptation presents a potential nourishment problem: A thinner shell has less calcium, which could cause deficiencies for the young reptiles.

Stewart and colleagues, who have studied skinks for years, decided to look for clues to the nutrient problem in the structure and chemistry of the yellow-bellied three-toed skink’s uterus.

Both birthing styles come with evolutionary tradeoffs: Eggs are more vulnerable to external threats, such as extreme weather and predators, but internal fetuses can be more taxing for the mother.

For the skinks, moms in balmier climates may opt to conserve their own bodies’ resources by depositing eggs on the ground for the final week or so of development.

Moms in harsh mountain climates, by contrast, might find that it’s more efficient to protect their young by keeping them longer inside their bodies.

In general, the results suggest the move from egg-laying to live birth in reptiles is fairly common—at least in historic terms—because it’s relatively easy to make the switch, Stewart said.

We tend to think of this as a very complex transition,” he said, “but it’s looking like it might be much simpler in some cases than we thought.

The skink-evolution research was published online August 16 by the Journal of Morphology.

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Narwhals Wearing Heart Monitors Reveal Danger Of Human Encounters

Normally when an animal is scared, it either remains very still and slows its heart rate and metabolism in hope that danger will pass like a possum playing dead, in an extreme case or the body revs up to power a “fight or flight” response.

But when narwhals get caught in fishing nets, surprisingly, they do both. Even as the narwhals pump their fins and tails as fast as they can to escape, their heart rates plummet to just three to four beats per minute.

Scientists report Thursday in the journal Science. For reference, that’s about as many beats per minute as a ground squirrel while it’s hibernating.

It’s the first time anyone has measured heart rate and performance at the same time for a diving cetacean, the group that includes whales, dolphins, and narwhals, says Terrie Williams, a wildlife ecophysiologist at the University of California, Santa Cruz and lead author of the new study.




The narwhals’ super-slow heartbeats were a surprise because animals need to pump enough blood around the body to supply oxygen to the brain and stay warm, Williams says.

What’s more, the lack of blood flow could prevent the narwhals’ bodies from removing nitrogen, which leads to decompression sickness, also known as the bends.

Narwhals have always been a bit of a mystery. It’s thought that there may be as many as 173,000 narwhals on Earth, but because of the animal’s remote habitat and cryptic nature, no one is really sure.

For starters, the animals live entirely above the Arctic Circle and tend to hang out in places where sea ice is so thick that it’s nearly impenetrable to ships.

They spend much of the day diving to depths of 4,500 feet or more where they hunt for halibut, cod, shrimp, and squid.

No one has ever seen a narwhal eat, by the way. Scientists know about their menu only from studying the gut contents of narwhals killed by local hunters.

In fact, the current study probably wouldn’t exist without indigenous hunters, since Williams and her coauthors relied on cooperation from the people of Ittoqqortoormiit, Greenland, to get access to the narwhals caught in their nets.

The local people would have normally harvested these animals, but instead agreed to let the narwhals go so they could be studied.

Before each animal was released, the scientists used suction cups to attach heart rate monitors and motion sensors called accelerometers to the entangled narwhals.

Williams suspects that other deep-diving cetacean species may also use this bizarre escape response when they become stranded.

If these animals also experience a cardiac freeze either as the result of noise pollution, entanglements, or other human impacts then perhaps the animals’ brains aren’t getting enough oxygen.

This might explain why some whales strand themselves again even after rescuers help them back into the waves.

I don’t have the proof,” says Williams, who published a paper earlier this year that showed noise pollution increases the amount of energy beaked whales expend on their dives.

But we are certainly seeking the proof.”

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Pass it on: Popular Science

Can Eating Too Much Make Your Stomach Burst?

I ate so much I’m about to burst!

Someone at your Thanksgiving table likely said this, after you’ve all stuffed your faces with turkey, mashed potatoes, sweet potatoes and the rest.

But how much would you have to eat in order for your stomach to actually burst? Is that even possible?

Interestingly enough, you can rupture your stomach if you eat too much,” says Dr. Rachel Vreeman, co-author of “Don’t Cross Your Eyes … They’ll Get Stuck That Way!” and assistant professor of pediatrics at Indiana University School of Medicine.

It is possible, but it’s very, very rare.

A handful of reports over the years document the tales of people who literally ate themselves to death, or at least came dangerously close.

Japanese doctors wrote in a 2003 case report that they believed it was a 49-year-old man’s “excessive over-eating” that caused his stomach to rupture, killing him.




And this 1991 case report describes a similar “spontaneous rupture” in an adult’s stomach “after overindulgence in food and drink.

Normally, your stomach can hold about one or one-and-a-half liters, Vreeman says — this is the point you may reach if you overdo it tomorrow, when you feel full to the point of nausea.

Pathologists’ reports seem to suggest the stomach is able to do OK handling up to about three liters, but most cases of rupture seem to occur when a person has attempted to stuff their stomach with about five liters of food or fluid.

It takes a certain amount of misguided determination to manage to override your natural gag reflex and continue to eat.

Which is, not surprisingly, reports of ruptured stomachs caused by overeating are most common in people with some sort of disordered eating, or limited mental capacity, Vreeman says.

Speaking of strong stomachs, you’d best have one in order to read this next paragraph. If vomiting isn’t happening, all that food and fluid still has to go somewhere.

The increasing volume of stuff in the gut puts pressure on the stomach’s walls, so much so that the tissue weakens and tears, sending the stomach contents into the body and causing infection and pain, Vreeman says.

Surgical intervention is necessary to repair a ruptured stomach and save the patient’s life.

In particular, she says, anorexics or bulimics may be at risk. In fact, Cedars-Sinai, the non-profit hospital in Los Angeles, actually lists this as a “symptom” of bulimia.

In rare cases, a person may eat so much during a binge that the stomach bursts or the esophagus tears. This can be life-threatening.

Other reported cases of spontaneous stomach rupture happen in individuals with Prader-Willi syndrome, a congenital disease that is characterized by, among other things, a kind of disordered eating.

An “intense craving for food,” resulting in “uncontrollable weight gain and morbid obesity.” according to the National Institutes of Health.

In a 2007 study examining the deaths of 152 individuals with the condition, 3 percent of those deaths were the result of gastric rupture and necrosis.

The takeaway here: This really happens, sometimes! Also: This is probably not going to happen to you.

Even if you’re starting to feel a bit sick or tired and overwhelmed from eating so much at Thanksgiving, you’re still far, far away from the scenario where you’re going to make your stomach actually explode,” Vreeman assures.

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5 Hard-Shelled Facts About Horseshoe Crabs

The plodding sea creatures have weird blood, weirder swimming habits, and a secret weapon that’s probably saved your life.

1. HORSESHOE CRABS ARE INCREDIBLY OLD.

Discovered in 2008, the 25 millimeter-wide Lunataspis aurora crawled over Manitoba 445 million years ago. This makes it the world’s oldest-known horseshoe crab.

Four species are with us today, all of which closely resemble their long-extinct ancestors.

Supposedly frozen in time, horseshoe crabs are often hailed as “living fossils” by the media.




Yet, appearances can be misleading. Evolution didn’t really leave these invertebrates behind. They’ve transformed quite a bit over the past half-billion years.

For instance, some prehistoric species had limbs that split out into two branches, but today’s specimens have only one.

2. THEY’RE NOT CRABS.

In fact, they aren’t even crustaceans. Unlike real crabs and their kin, horseshoe “crabs” lack antennae.

So, where do the strange ocean-dwellers belong on the arthropod family tree? Biologists classify them as chelicerates, a subphylum that also includes arachnids.

Members possess two main body segments and a pair of unique, pincer-like feeding appendages called chelicerae.

3. EACH ONE HAS A HUGE ARRAY OF SIGHT ORGANS.

Large compound eyes rest on the sides of their shells. Come mating season, these bean-shaped units help amorous crabs locate a partner. Behind each one, there’s a small, primitive photoreceptor called a lateral eye.

Towards the front of the shell are two tiny median eyes and a single endoparietal eye. On its underside, a horseshoe has two “ventral eyes,” which presumably help it navigate while swimming.

4. BABIES CAN SWIM UPSIDE DOWN.

Walking around on the ocean floor is generally how horseshoe crabs get from point A to point B.

Nevertheless, young ones will often flip over and start propelling themselves through the water, using their gills as extra paddles. With age, they do this less frequently.

5. THE SPIKED TAIL HAS SEVERAL USES.

Stinging isn’t one of them, despite what many falsely believe. Among its uses are assuming rudder duties and helping the arthropod right itself after getting stuck on its back.

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Over 200 Pterosaur Eggs And Embryos Has Been Found At A Site In China

An ancient site containing more than 200 fossilised eggs belonging to ancient flying reptiles known as pterosaurs has been found.

The eggs belong to a species called Hamipterus tianshanensis, which soared over what is now north west China about 120 million years ago.

The palaeontologists who made the discovery note both the “extraordinary quantity of eggs”, and the fact some of them contain “the first pterosaur three-dimensional embryos”.

This level of preservation allows researchers to learn more about the behaviour of these prehistoric creatures.

Previous evidence of pterosaur reproduction has been rather lacking, limited to a handful of eggs from Argentina and China identified in 2004.

Prior to this, there was no evidence at all these reptiles laid eggs.

But the new discovery, which consists not only of eggs but the bones of adults as well, paints a vivid picture of a nesting colony.




The findings were published in a paper led by Dr Xiaolin Wang of the Chinese Academy of Sciences in the journal Science.

Dr Wang and his collaborators outline how they used CT scans to look inside the eggs, 16 of which contained embryos that were somewhat intact.

From these embryos, the scientists could see that the structures supporting the pectoral muscles – crucial for flight – were noticeably underdeveloped.

This allowed the scientists to infer that when these animals hatched, they were unable to fly. The newly hatched pterosaurs would therefore have required care and attention from their parents if they were to survive.

The fossils also reveal more secrets about pterosaur lifestyles.

“The find reinforces the view that pterosaur eggs were soft-shelled and needed to be buried,” said Dr Charles Deeming, a biologist at the University of Lincoln who was not involved in the study.

This draws comparison with modern day lizard eggs, and suggests that while the pterosaurs may have cared for their offspring, they didn’t incubate them like birds. Instead, they relied on the earth to keep their eggs warm.

The rarity of such a fossilisation event makes this discovery, and the knowledge gained from it, all the more precious.

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Mussel-Inspired Plastic May Lead To Self-Repairing Body Armour

Scientists have developed a new mussels inspired plastic that can stretch without snapping and repair its own molecular bonds, paving the way for self- repairing body armour.

The material could also find an application in the joints of robotic arms that need to bear heavy weights but still move around, researchers said.

Mussels and some other molluscs hang onto solid surfaces using an adhesive protein and tough, plastic like fibers, which are extremely strong and can repair themselves when a few molecular bonds within them are broken, they said.

The study, published in the journal Science, found that for a mussel, these stretchy yet strong fibres come in handy when a wave hits.




Researchers from University of California, Santa Barbara in the US created a plastic with these same properties by mimicking the chemistry the mussels use.

Molecular bonds between iron and an organic compound called catechol make the material difficult to break or tear, while still allowing it to remain stretchy, they said.

The iron-catechol bonds dissipate energy from something hitting or stretching the material. These “sacrificial bonds” break, but the overall structure stays intact.

It is like a bike helmet: if you are in a bike accident, the foam inside the helmet crushes and dissipates some of the energy.

“All that energy that would have gone into a skull fracture, instead goes into the helmet,” Megan Valentine from University of California said.

In our case, instead of foam we have this sacrificial bonding that protects the underlying polymer system,” Valentine said.

By sacrificing the iron-catechol bonds, the material can stretch by 50 per cent. Then, once the stress is taken away, the bonds reform, making it reusable, researchers said.

Adding these bonds results in the plastic being 770 times stretchier and 58 times stronger than it is without them, they said.

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Laboratory Cultured Sea Urchins

Sea urchins can be raised from egg to egg in the laboratory.

With proper food, the larvae can be grown to maturity in about 3 weeks. When mature larvae are exposed to the proper chemical cues metamorphosis occurs.

Over the next 5 days the small urchins develop internal organs and then begin to feed. Sexual maturity can be reached in as little as 4.5 months.

By then the urchin is about a centimeter in diameter. Several different approaches to the study of developmental genetics are covered.




These include:

  1. Hybrids between the sand dollars Dendraster and Encope, in which both crosses produce offspring that have predominantly paternal characteristics;
  2. a preliminary description of two mutants, one which produces abnormally shaped blastula that may lead to a significant number of exogastrulae, and another that produces a large number of four- part symmetrical urchins;
  3. urchins produced by parthenogenetic activation and from reaggregated larval cells.

Almost all of sea urchin genetics has been limited either to studies of inter-specific and inter-generic hybrids or to the area of molecular biology.

To some extent, hybrid studies have been forced on the sea urchin embryologist because genetics at a more refined level has not been possible.

Hybrid studies have been useful and they played a particularly important part in the early investigation of the role of the nucleus vs. that of the cytoplasm.

Horstadius (1973) pre-sents an extensive discussion of these early investigations.

In many ways, research at the molecular level is just beginning, in spite of the fact that the literature is already very extensive.

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Meet The Russian Biologist Who Is Also A Pioneer Of Modern Genetics

Nikolai Konstantinovich Koltsov was a Russian biologist and a pioneer of modern genetics.

Koltsov graduated from Moscow University in 1894 and was a professor there (1895-1911).

He established and directed the Institute of Experimental Biology in the middle of 1917, just before the October revolution and was a member of the Agricultural Academy.

In 1920, Koltsov was arrested as a member of the non-existent “Anti-Soviet Tactical Center” invented by the VCheKa.

Prosecutor Nikolai Krylenko demanded the death sentence for Koltsov (67 of around 1000 arrested people were executed).

However, after a personal appeal to Vladimir Lenin by Maxim Gorky Koltsov was released and was restored to his position as the head of the Koltsov Institute of Experimental Biology.




Nikolai Koltsov worked on cytology and vertebrate anatomy. In 1903 Koltsov proposed that the shape of cells was determined by a network of tubules which he termed the cytoskeleton.

In 1927 Koltsov proposed that inherited traits would be inherited via a “giant hereditary molecule” which would be made up of “two mirror strands that would replicate in a semi-conservative fashion using each strand as a template“.

These ideas were confirmed to have been accurate in 1953 when James D. Watson and Francis Crick described the structure of DNA.

Watson and Crick had apparently not heard of Koltsov. US geneticist Richard Goldschmidt wrote about him: “There was the brilliant Nikolai Koltsov, probably the best Russian zoologist of the last generation, an enviable, unbelievably cultured, clear-thinking scholar, admired by everybody who knew him“.

In 1937 and 1939, the supporters of Trofim Lysenko published a series of propaganda articles against Nikolai Koltsov and Nikolai Vavilov.

They wrote: “The Institute of Genetics of the Academy of Sciences not only did not criticize Professor Koltsov’s fascistic nonsense, but even did not dissociate itself from his “theories” which support the racial theories of fascists“.

His death in 1940 was claimed to have been due to a stroke. However, the biochemist Ilya Zbarsky revealed that the unexpected death of Koltsov was a result of his poisoning by the NKVD, the secret police of the Soviet Union.

The same day his wife, the scientist Maria Sadovnikova Koltsova, committed suicide.

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Ancient Fossilized Salamander Reveals Its Last Meal

Accessing the complete anatomy of an extinct animal, i.e. both its external and internal aspects, has often been the dream of palaeontologists.

Indeed, in 99% of cases, fossils are only represented by hard parts: bones, shells, etc. Fossils preserving soft tissues exist, but they are extremely rare.

However, their significance for science is enormous. What did the animal look like?

What did they eat? How did they live? Most of these questions can be answered by exceptionally preserved fossils.

The newly studied fossil externally looks like a present-day salamander, but it is made of stone.




This fossil “mummy” is the only known specimen of Phosphotriton sigei, a 40-35 million years old salamander and belongs to the same family as the famous living fire salamander.

It is unfortunately incomplete: only the trunk, hip and part of hind legs and tail are preserved.

Until very recently, the only thing palaeontologists could tell about this specimen was visible anatomical details, such as the cloaca, the orifice used for reproduction and by digestive and urinary canals.

Indeed, though it was discovered in the 1870s, it was never studied in detail.

The quality of preservation is such that looking at the tomograms feels like going through an animal in the flesh.

At least six kinds of organs are preserved in almost perfect condition, in addition to the skin and skeleton: muscles, lung, spinal cord, digestive tract, nerves, and glands.

But the most incredible is the preservation of frog bones within the stomach of the salamander. Salamanders almost never eat frogs or other salamanders, though they are known to be quite opportunistic.

Was it a last resort meal or a customary choice for this species? This, unfortunately, will probably never be known.

These new results are described by Jérémy Tissier from the Jurassica Museum and the University of Fribourg in Switzerland, and Jean-Claud Rage and Michel Laurin, both from the CNRS/Museum national d’histoire naturelle/UPMC in Paris.

Author Michel Laurin notes, “This fossil, along with a few others from the same lost site, is the most incredibly well-preserved that I have seen in my entire career. And now, 140 years after its discovery, and 35 million years after the animal died, we can finally study it, thanks to modern technology. The mummy returns!

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