What do you call a squid with two arms?

Nectocaris pteryx, of course. Which means, erm, finned swimming crab. One of the many weird squidgy things found in the famous Burgess Shale of British Columbia in Canada was a 5cm long blob with fins, stalked eyes and a pair of tentacles. There had been only one specimen collected originally, and while a few researchers had studied it - including Stephen Jay Gould and Simon Conway Morris - it wasn't until this year that it has been more firmly identified as an early cephalopod.

A group has studied a further 90 specimens collected by the Royal Ontario Museum and has recognised features of later relatives that give credence to the cephalopod tag. This is significant as it drags the origins of cephalopods back in time by a good 30 million years to 505 million years ago.

Unlucky for some

Opals have a reputation for being unlucky, and there are various possible reasons floating around the internet it turns out. The most plausible is the negative press the stone got from Sir Walter Scott's novel 'Anne of Geierstein'. I'd never heard of it. Apparently somebody dies after their opal gets wet and turns colourless. Prior to the book, opals were considered very lucky. Power of the press.

Lucky or unlucky, opal can be a beautiful stone. Like jet, it's another stone saddled with the unfortunate designation of mineraloid, because it's essentially hydrated quartz. The water content varies up to between 15-20%, and this will affect the stability of what can be a temperamental stone. There's quite a range - milk, jelly, fire, boulder, cherry - but when most people think of opal it's of the precious gemstone types. The vivid flashes of colour that can be seen in some varieties is due to the way the quartz is arranged in its construction. Tiny spheres of quartz are packed together in grids and this structure will diffract light passing through to create a play of colour.

It's a bit of a pain to work as a gemstone - it's prone to cracking and usually the best display face will require careful positioning. Like with most gemstones now, there are a few synthetic forms available now. Gilson opal was the first effective one, developed in the 70s, but I saw some Japanese stuff a couple of years ago that looked amazing. Expensive, but amazing. The bit shown above is from Welo in Ethiopia. The material has been around for a few years, but I've thought it a little too expensive for me to find a market for. Last year, though, a new site was found, there were a bunch of new sellers around and the price was very good. I bought a load and I'll get some more this year.

Subtle dig

Yesterday an American guy came in and came up to the counter pretty quickly, his wife hanging back by the door. He seemed a little edgy.

'You have someone that carbon-dates all this stuff for you?'

'No - carbon dating is only useful up to about 40,000 years, but there are other pairs of isotopes that are used for longer time periods. And other methods..... [explanation of other dating techniques] ...and the material is almost always identified at source by the collector.'

'Ah - so you rely on the word of others?'

'Well, of course - why wouldn't I? It's in the best interests of the collector and seller to provide as much accurate information as possible about their product.'

'Did you know the Grand Canyon has been underwater five times? You can tell from the rocks.'

'Well - do you mean during its formation?'

'So is there someone that authenticates all these ages for you?'

'Err, well, no. There's no official body for the authentification of fossils - you might take something along to a museum or find a university with a geology department, though. It comes from all over the world - lots of different localities and the experts in those particular sites and fossil faunas will be spread all over, too. I have spent a long time studying geology and palaeontology, though, and most people in the trade know their subject pretty well.'

'So - you DO have to reply on the word of others. That must make it difficult for you, working here.'

'No. Not in the slightest.'

I was expecting him to go on. He seemed to have an issue with the dating, and I've found that the underlying reason is almost always a belief in Young Earth Creationism. He seemed to think he had made some significant point, however, and left with a curt goodbye. I have had similar conversations before, where the individual questions the ages of the fossils in the shop, makes some vague reference to upside-down trees, the subjectivity of time, buried laser guns or something and then quickly legs it feeling they have left my belief in the scientific process rocked to the core.

I find it strange. If you have these deeply-held beliefs, don't be afraid to test your thinking on them - see how they stand up in conversation. If you think I'm being naive, insincere or even deceitful by accepting and passing on the word of people who have invested a large chunk of their life studying certain fossil beds, tell me why. This guy - to me - was being hypocritical. I find it hard to believe he has never taken the word of another at face value. He didn't get round to telling me about his beliefs. I may have him pegged wrongly, but I don't think so. I'd have liked to discuss it further with him; find out why he doubted the ages. Anyway. Whatever floats his boat. Or Noah's.

Octopurse

There's a little bit in the news today about the argonaut. It's often called 'paper nautilus', but it's an octopus; a little one that floats around near the surface of the ocean. Females are bigger then the 1-2cm males, but still only reach around 10cm. What's interesting about them, though, is that before they lay eggs, the females secrete calcite from the tips of a couple of specialised webbed tentacles and form a spiral shell. She will live in the shell, sticking the head and tentacles out the front, but the main purpose seems to be to protect the eggs. Most octopuses lay theirs in holes in rocky substrates. In their lairs. I wish I had a lair.

Argonauts are known to bob around just below the water surface and draw in a pocket of air to store in the shell, and this leads to another function of the shell. This air bubble can be used to control the buoyancy of the animal, greatly reducing the effort needed to move up and down through the water column. Effort that can then be expended by the argonaut in more profitable ways - going to the pub, making rock buns, etc. Obvious advantage.

A squashy, tentacley thing living in a spiral shell in the ocean? Hmm. Sound like an ammonite? The closest living relative of the ammonite is the octopus, not the spiral-shelled, tentacle-flapping nautilus, BUT this isn't a cephalopod family heirloom; the argonaut has developed this afresh, the clever little pulpbag. What's going on? Covergent evolution? Could be. Octopuses are brilliant.

Sharp stone!

Was watching BBC's Horrible Histories this morning with my son before school and this sketch came on. It's generally a very good show - informative, engaging, and certainly teaches my son about history while he's unaware...

Anyway - coincidentally I got three little Neolithic scrapers in the post today. I don't know masses about archaeology, but there's something appealing about 'caveman tools'.

Written in the sand

An article in yesterday's New York Times about the interpretation of trace fossils found in a layer of the micritic limestones of the Green River Formation. This famous site is where I get most of the fossil fish I sell, so it caught my eye.

Strange patterns in a layer of the rock had led to some interest. Anthony Martin of Emory University identified fin and mouth marks associated with graze feeding on the substrate, and due to the estimated size of the fish responsible, suggests Notogoneus osculus. The significance of the find is that it had previously been thought the oxygen levels would have been too low at this depth of 35 to 50 feet to allow fish to swim along the bottom of the lake. This would also help account for the unusually large number of fossils from the site - a de-oxygenated layer greatly boosts the chances of fossilisation. The fact that this Notogoneus had been grubbing around the lake bottom shows that - at least for some time - there was enough oxygen down there for fish to feed.

Cousin Ug

There was a nice little piece in today's Metro about Neanderthals. The main topic was another hot potato of hominid history - just how well did Homo sapiens get along with his new neighbour Homo neanderthalensis when he moved into Europe between 50 and 100 thousand years ago? A passing nod on the way to the morning hunt? Did they invite each other to their respective barbecues? Or did it go a little further than that?

Whether or not there was interbreeding has been a subject for debate since shortly after the first Neanderthals were first identified as a separate hominid and named in 1864. The first evidence of them had been found in Belgium in 1829, with subsequent finds in 1848 (Gibraltar) and 1856 (the 'original' find in the Neander Valley in Germany). For some time there has also been debate as to whether Neanderthals should have species status or be a sub-species of modern man. Current thinking has them standing proud and alone as their own species. It seems very likely we share Homo heidelbergensis as an ancestor.

Anyway, the piece was due to the publication in today's Science of new research on the Neanderthal genome. Information has been pieced together from three individuals to provide a far better understanding of the genetic make-up of our closest relative. Perhaps the most interesting find was that Neanderthals are genetically closer to current non-Africans than with Africans. This suggests a degree of interbreeding. Modern man and Neanderthals did indeed get it on. Between one and four percent of modern man's genome is Neanderthal. I reckon I'm closer to one percent, but there's a guy that gets my bus that's got to be pushing four.

Neanderthal man went missing around 30,000 years ago. If anyone spots him, please call the police. We all miss him.

Giant dwarf

The other week I was struck with a sudden desire to know the height of the world's tallest dwarf. The feeling passed, and I still haven't found out. But then this story caught my eye - remains of a little-ish dinosaur, Magyarosaurus dacus have been identified as a dwarf sauropod. The actual find was made in Transylvania in 1895, and at the time the discoverer suggested it may have been an 'island dwarf' species. This process is an evolutionary scaling down demonstrated now in many examples - my favourite being a species (or race, possibly) of dwarf mammoth found on Wrangel Island, to the North East of the Russian mainland, that may have only died out around 1700 BC.

For a long time it had been thought the find represented a juvenile, as there were larger 'normal' sized sauropod bones being found at the same site. Recent research, though, suggests the smaller bones were those of an adult animal and so a dwarf sauropod. It's still the size of a decent horse, this thing. It's just small for a sauropod, which usually - Supersaurus, Argentinosaurus, Diplodocus, etc - were big enough to empty a good-sized lake with a belly-flop.