Here's one relative you're probably glad didn't pop round for Christmas.

X-rays of a 385-million-year-old German shark suggest we last shared a common ancestor with sharks more than 400 million years ago, according to UK, Irish and US scientists.

CT scans of Gladbachus - an extinct genus of chondrichthyan, the class of fish that sharks belong to, which lived in the Middle Devonian era - revealed an unprecedented combination of primitive and specialised features within the jaws, gills, teeth and scales.

These new data shed light on the origin of modern vertebrates, confirming sharks as early specialists, while pushing a minimum date for our last common ancestor with sharks back to the base of the Silurian, some 440m years ago.

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Several of these early lineages converged on shark-like characteristics such as multiple gill slits, but these innovations might be related to filter-feeding rather than the predatory habits of their more familiar descendants.

"Gladbachus offers a glimpse of early chondrichthyan diversity yet to be discovered," the researchers wrote in the journal Proceedings of the Royal Society B.

The weather in Westeros

Scientists have used a climate model to simulate and explore the climate of the world of Game of Thrones. Photo / File
Scientists have used a climate model to simulate and explore the climate of the world of Game of Thrones. Photo / File

Winter is coming, as anyone who watches the hit TV series, Game of Thrones, knows.

Some even have their own theories for what causes the strange extended seasons in that world of dragons, kings, queens, and magic.

But scientists from the Universities of Bristol, Cardiff, and Southampton have gone one stage further, by using a climate model to simulate and explore the climate of the world of Game of Thrones.

The results show that The Wall, where the land of Westeros is guarded from the White Walkers, has a climate in winter similar to that of Lapland, whereas Casterly Rock, the stronghold of the scheming Lannisters, has a climate similar to that of Houston, Texas, and Changsha in China.

The wind speeds and directions predicted by the climate model explain phenomena such as the dominance of the seas by the Iron Fleet, the likely attack plans of invading dragon hordes from Essos, and the trading routes between Westeros and the Free cities across the Narrow Sea.

The temperatures predicted by the climate model indicate the likely hibernation zones of White Walkers in summer.

The full results have been published in a mock journal article - also available in Dothraki and High Valyrian - and is written by Samwell Tarly, who is studying to become a "Maester" in the Citadel in Oldtown in Westeros.

Samwell showed that the extended seasons could be explained by a "tumbling" of the tilt of the spinning axis of the planet as it orbits the sun, in such a way that the same Hemisphere always tilts towards the sun.

He also modelled the global warming that would occur if concentrations of greenhouse gases in the atmosphere were to be doubled, due to increases in carbon dioxide and methane emissions from dragons and the excessive use of wildfire.

His estimate of 2.1C global warming for a doubling of carbon dioxide was within the range predicted by the Intergovernmental Panel on Climate Change for the real Earth, of 1.5C to 4.5C.

And, according to Professor Dan Lunt, from the University of Bristol's School of Geographical Sciences, the calculations weren't too far from science as we might think.

"Because climate models are based on fundamental scientific processes, they are able not only to simulate the climate of the modern Earth, but can also be easily adapted to simulate any planet, real or imagined, so long as the underlying continental positions and heights, and ocean depths are known."

The science of... vengeance

The human trait of enjoying the suffering of those who have wronged us has also been observed in chimps. Photo / 123RF
The human trait of enjoying the suffering of those who have wronged us has also been observed in chimps. Photo / 123RF

If you've ever enjoyed watching the suffering of someone who you think deserved it - a bothersome sibling who got a telling off - there's a lot more to it than you might think.

It's known from previous studies that we perceive a perpetrator's pain as a just punishment and a tool to penalise misbehaviour.

But, more than just schadenfreude, we also feel a sense of spite when we witness the disciplinary measure.

Until now, not much has been known about the evolutionary origin of this behaviour.

Scientists from Germany's Max Planck Institute explored the question at what age we develop the seeming motivation, and whether it also exists in our closest relatives - chimpanzees.

To investigate children's behaviour, the researchers used a puppet theatre in which two characters each behaved differently.

There was a friendly character, who gave the children their favourite toy back, and an unco-operative one who kept the toy for themselves.

Further, there was a puppet that played the punishing role and pretended to hit the other two with a stick.

The young audience, aged 4 to 6 years, could decide if they wanted to watch the pretend hits by paying with a coin, or if they would prefer to exchange the coin for stickers.

In the case of the friendly puppet, the children largely refused to observe how it suffered.

But in the case of the anti-social puppet, the 6-year-old children's preference to reject the stickers and spend their coins witnessing the punishment was significant.

They even experienced pleasure by watching him suffer, shown in their expressions.

In contrast, the 4 and 5-year-old children did not show this behaviour.

The scientists observed similar occurrences in chimpanzees.

Their desire to penalise antisocial behaviour was studied at Leipzig Zoo with the help of two zookeepers, who also slipped into contrasting roles - social and antisocial.

While one regularly fed them, the other took their food away.

In this situation also, another person pretended to beat them both with a stick.

As with the children, a significant number of chimpanzees made an effort to witness the disliked keeper being punished.

To do so, they had to open a heavy door to a neighbouring room from where they could witness the scene.

As for the friendly zookeeper, they refused this option and even protested strongly when pain was inflicted on them.

"Our results demonstrate that 6-year-old children and even chimpanzees want to avenge antisocial behaviour and that they feel an urge to watch it," said researcher Natacha Mendes, whose work has just been published in the journal Nature Human Behaviour.

"We can not definitely say that the children and chimpanzees felt spite," added co-author Nikolaus Steinbeis, of the Max Planck Institute and University College London.

"However, their behaviour is a clear sign that 6-year-old children as well as chimpanzees are eager to observe how unco-operative members of their community are punished."

Good eye-dea - a nice cup of tea

Drinking a cup of hot tea at least once a day may be linked to a significantly lower risk of developing the serious eye condition, glaucoma, finds a small study published online in the British Journal of Ophthalmology. Photo / 123RF
Drinking a cup of hot tea at least once a day may be linked to a significantly lower risk of developing the serious eye condition, glaucoma, finds a small study published online in the British Journal of Ophthalmology. Photo / 123RF

Drinking a cup of hot tea at least once a day may be linked to a significantly lower risk of developing the serious eye condition, glaucoma, finds a small study published online in the British Journal of Ophthalmology.

But drinking decaffeinated and caffeinated coffee, decaffeinated tea, iced tea and soft drinks doesn't seem to make any difference to glaucoma risk, the findings show.

Glaucoma causes fluid pressure to build up inside the eye, damaging the optic nerve.
It's one of the leading causes of blindness worldwide, and currently affects 57.5m people, and is expected to increase to 65.5m by 2020.

Previous research suggests that caffeine can alter intraocular pressure, but no study so far has compared the potential impact of decaffeinated and caffeinated drinks on glaucoma risk.

Researchers looked at data from the 2005-2006 National Health and Nutrition Examination Survey in the US, a nationally representative annual survey of around 10,000 people.

Among the 1678 participants who had full eye test results, including photos, 84, or around 5 per cent, adults had developed the condition.

They were asked how often and how much they had drunk of caffeinated and decaffeinated drinks, including soft drinks and iced tea, over the preceding 12 months, using a validated questionnaire.

Compared with those who didn't drink hot tea every day, those who did had a lower glaucoma risk, the data showed.

After taking account of potentially influential factors, such as diabetes and smoking, hot tea-drinkers were 74 per cent less likely to have glaucoma.

But no such associations were found for coffee - caffeinated or decaffeinated -
or with decaf tea, iced tea or soft drinks.

The authors stressed this was an observational study so no firm conclusions could be drawn about cause and effect, and the absolute numbers of those with glaucoma were small.

Information on when glaucoma had been diagnosed was also unavailable, and the survey didn't ask about factors like cup size, tea type, or the length of brewing time, all of which might have been influential.

But tea contains antioxidants and anti-inflammatory and neuroprotective chemicals, which have been associated with a lowered risk of serious conditions, including heart disease, cancer, and diabetes, say the researchers.

And previous research has suggested that oxidation and neurodegeneration may be involved in the development of glaucoma, they add, concluding: "Further research is needed to establish the importance of these findings and whether hot tea consumption may play a role in the prevention of glaucoma."