Monday, 26 September 2011

A present

A taxi pulled up outside the shop today, and the driver got out. He came in and I recognised him from last week, when he'd found a couple of minerals he'd been looking for. I can't remember exactly what. I think maybe aquamarine and something else.

'Hi. Just wanted to say I was delighted with the crystals I got here the other day, and I brought you this.'
He put down a bottle of blackcurrant Lucozade.
'Oh. Thanks very much!'
'You're welcome. Bye!'


Friday, 23 September 2011

Dinner with the Denisovans

And maybe a little more than dinner in a few cases.

I linked a couple of news stories to the Mr Wood's Fossils Facebook page today which are about the movement of humans across the globe. One was about how DNA studies shed a little light on how aboriginal Australians made their way there, and when. The other was a little more general, and concerned the gradual population of Asia with Homo sapiens.

When we humans spread ourselves around, it was eventually at the expense of our closest relatives. Neanderthal is the most famous non-human hominin to have been been out-competed to extinction, but let's not forget old Uncle erectus and Auntie Denisova. Who? Not much is known of the Denisovans. In fact, only a bit of finger bone and a tooth. It's thought they were part of a migration from Africa between that of the Homo erectus and modern humans, and the mitochondrial DNA results of the bone analysis suggest a common ancestor with both the Neanderthal and us at about 1 million years ago, then with the Neanderthals alone at a later date. So - once split, the Denisovans toddled off across Asia and made themselves at home.We know they lived in the Altai Mountains of Siberia around 40,000 years ago - that's where/when the fossils are from - but they probably were reasonably widespread.

They would have lived alongside both Neanderthals and humans, and those first groups of humans that passed through Asia on their way to Indonesia, Australia and points Antipodean show a higher percentage of shared DNA with the Denisovan line than those that came along later. Some level of interbreeding went on with the locals as these migrations passed through.

Anyway - just a little more to add to the storyline. There are a few sites that illustrate the human migration pretty well, though keeping these up to date must be a constant task. Have a look at these - The Bradshaw Foundation's Journey of Mankind, and the Genographic Project's Atlas of the Human Journey. It's far easier to understand when there's a map and a big arrow, I think.

Wednesday, 14 September 2011

Clash of the titans

Planet Dinosaur kicks off on BBC1 at 8.30 tonight with a battle between two stars of the commercial dinosaur world. Carcharodontosaurus saharicus and Spinosaurus aegyptiacus were both busy terrifying what's now Northern Africa around the middle of the Cretaceous Period. They were huge animals. Enormous. With big teeth and claws. Which are readily available for sale! They are well represented in the remains found in the Kem Kem region around Taouz, Morocco, one of the biggest and most productive dinosaur sites ever found. Before material started coming out of there in quantity, the only dinosaur teeth relatively easy to buy were from a couple of US sites and they were far more expensive. The Kem Kem teeth are so plentiful they have allowed dinosaur fossils to be sold at prices affordable to children with a little pocket money. The better examples are, of course, more costly, but a dinosaur tooth is still a dinosaur tooth. The possession of real fossils can strengthen a passion for the subject and instill desire for further learning; create a depth of respect for history that doesn't always come from pictures in a book.

Spinosaurus has seen a fairly rapid rise in fame. When I was a kid, the dinosaur hall-of-fame included  Tyrannosaurus rex, the undisputed king, Stegosaurus, Diplodocus, Triceratops and the sadly-missed Brontosaurus. Today's crop of dinosaur superstars has to have Velociraptor and Spinosaurus in there, too, thanks to the Jurassic Park factor. There's no disputing the effect a blockbuster movie or big-budget tv series can have. Amber sales are still influenced by the first of the Jurassic Park films, and Attenborough's programs on early life shown late last year sparked a noticeable run on trilobites for months after. Good for business, of course, and I'm looking forward to the day when a fossil sea urchin gets to the last round of X Factor. Probably never happen. Anyway. I hope Planet Dinosaur meets expectations; Spino vs Carch is a brilliant way to open.

Friday, 9 September 2011

Bear bones

After a few years without, I've finally got a few cave bear paws in stock. The price went a little crazy, and I'm not sure I'll be able to buy them again unless a new find is made. Not unlikely, but just a case of wait-and-see. I came very close to buying a complete cave bear skeleton a while ago, but chickened out thinking I'd not have the space to display it. Wish I had now, as the price has trebled since. At this point, as some seem to get disproportionally upset by this, I should point out that these paws are from Ursus uralensis, which is not the true cave bear, but rather more similar to a modern grizzly. They still spent long enough in caves to fall down big holes and pile up in great numbers, though, so I'm not particularly bothered with the distinction. Fact is that cave bears were so named because most of their fossils were found in caves, so it was assumed that's where they spent most of the time. The same assumption can easily be made for uralensis, though they were clearly different animals.

Proper cave bears - Ursus spelaeus - lived all across Europe until a little over 27,000 years ago at the onset of the peak of the last ice age. Possible reduction in available foods and likely competition for shelter with humans are thought to be responsible for their demise. They looked like large brown bears, but had slightly wider skulls and heavier limbs. Their dentition was slightly different, too, and it's thought their diet was more vegetarian than that of brown bears.

The Carpathian Mountains have proved a huge source of cave bear remains, with sites in Romania and Slovakia being particularly rich. We had a cave bear skull once, which sold for a good bit less than it'd cost to replace now. Teeth are reasonably easy to keep in stock, and are good sellers, while claws are harder to come by and don't sell as well. We even had a baculum once, I remember. I had to make an extra little sign to sit beside it, saying 'Yes, really.' Baculum are penis bones, which almost all mammals have, to some extent. Not humans, as you may have noticed. I've linked the word above to the Wiki entry, to save you googling 'penis bone'. I'd advise against that. Walrus baculum, known in Alaska as oosik, can be two feet long, and were used as clubs. What a way to go.

Friday, 2 September 2011

Amber - caution

The other day a woman approached Riley and said she was looking to replace an amber pendant she'd had when she was young. It had been very dear to her and had been lost. Might we have anything similar? Riley got out the bag of amber pendants we have before asking her to describe it. It had a seahorse in it, the woman explained.

'Ah', said Riley. Sadly he couldn't find a pendant that matched the one she lost. If seahorses were ever arboreal it was for a very short period in their evolutionary history. They just weren't cut out for climbing.

Fake amber isn't uncommon. Commercial amber is usually from one of three sources - the Baltic Sea, the Dominican Republic and the Chiapas Hills in Mexico. There are plenty of other places amber's found, but not in such quantities, and not of such quality. Amber is, of course, fossilised tree resin - in the case of the Dominican stuff, it's mostly from the hymenaea tree. In Baltic examples it's from pine or eucalyptus trees. I've seen insects 'planted' in reconstituted amber, and in plastic, and very often if it looks too good to be true, it possibly is... For something to become trapped in tree sap it has to be somewhere near a tree. If your prized piece of amber contains a seahorse, or a strawberry, or a digital watch, you should be suspicious.

There are ways to check for fakery, though. Ether or acetone (or paint thinner, or nail polish remover) will usually start to melt plastic but leave amber unharmed. Sticking a heated needle into the piece will give off a tell-tale smell. Amber gives off a pine sap smell (perhaps unsurprisingly) while plastic will give of the smell of burnt plastic. You knew that. Amber can be scratched by a coin, where most of the plastics used are a little harder. All of these are a little destructive. I'd expect were you to blow up pieces of plastic and amber with the same amount of gunpower, the fragments of plastic would fly further, but it's not really a test you'd want to put your amber through. Alternatively, you can putting your piece in some salt water. Amber should float. Or try a UV lamp - amber fluoresces as shown in this video.

Lastly, some sell copal as amber. This may simply through ignorance, however, and isn't really on the same level of deceit as bugs in plastic, if it can be called deceit at all. Copal is basically young amber - still resin from trees - and can be found containing insects in Madagascar, Bolivia, Colombia and a few other sites. These places produce material ranging in age from around 100,000 to 500,000 years old, where most amber is 25 million years old and more. Copal isn't as hard as amber, so doesn't work as well for jewellery. It tends to be paler in colour, too.