Merry Christmas!

Just wanted to wish everyone a mightily jolly holiday. If you're reading this on Christmas Day, by the way, haven't you got something better to do?

It's a funny old Christmas at this end - lurgified, surrounded by half-filled boxes, and gradually creeping towards getting the right forms... Actually, we now have the working permit from China (which means we passed the medicals, which is a relief), and the only remaining thing is to actually get the visa, book the flights and go. It looks as though we need to be in China on or near Jan 10th, because of a grant I've had from the Chinese Academy of Sciences, so the next couple of weeks will be getting quite frenetic. And also, we've just found out our shipping company won't carry fossils for us, which is fun! Three steps forwards, and half a dozen sideways...

Still, it's definitely getting there. I think. And I think "there" is somewhere vaguely near where we want it to be. Maybe. The good news is we'll arrive in time for the Chinese New Year, so it doesn't matter that this year's Christmas is a bit of a non-event for us - we'll just make up for it a few weeks later. Cheers all!

(And just because we can't have a post with no pictures at all, here's Toad, getting confused by all the festivities. We'll introduce him properly in a bit.)

Belgian adventures

Last weekend we were in the Belgian city of Ghent for the annual conference of the Palaeontological Association. As always, we saw all the people we hadn’t seen since the last annual meeting, met new ones, got to know about the latest in palaeontological research. Since this is a palaeontological meeting, copious amounts of alcohol were also involved. (Naturally, our imbibing was moderate, and I would say that even if my mother weren’t reading this blog.)

Architecturally Ghent is very interesting, at least those bits I managed to see of it in the short intervals going to and coming from the conference hall. I don’t know what this building is, but it looks impressive.

This is one of three cathedrals. I didn’t find out why they needed so many, and all on the same street.

There was a bit of snow while we were there, as you can see.

Getting back was interesting, which is of course in this context a euphemism for unpleasant. We waited in Brussels for 5 hours, two hours of which were turning up early, and one and a half the gap between our train (cancelled) and the next. That train finally left another 90 minutes late. Still, we were a lot better off than the people at Heathrow, or even St Pancras – at least we knew that we would eventually get on a train, and we had a warm waiting room and moderately comfortable seats. The leg from London to Leeds went smoothly, with just long enough to get something to eat. Since it was 9.30 p.m. by this point, the train wasn’t crowded. The really unpleasant part of the journey was the two and a half hour wait in Leeds, between our train arriving around midnight and the sole Huddersfield train leaving.

This post is getting quite long enough, and I don’t want it to turn into a whinge, so I won’t mention that we both acquired a nasty cold while abroad and aren’t fit for anything but drinking hot drinks and surfing the internet.

Snow? What snow?

It always amazes me what can survive the sort of weather we've been having lately. Small birds suffer in harsh winters, and invertebrates are at risk of freezing solid. In Yorkshire we've had a good 8-10 inches of snow, temperatures down to -12C, and snow lying solidly for about two weeks. You've seen the pictures, so you know what it's been like. Now, I can quite happily understand how things survive underground, or in warm bits like decaying planty stuff, but you'd think that small creatures living exposed to the elements would have a hard time of it. A well-known method of killing insects for entomological research is to freeze them, after all.
   So, just as it was getting dark today, I went out into the garden to beat the Leylandii hedge with a box, to see what was lurking on it. The results from an truly minuscule amount of looking are as follows:

This one is a psyllid or jumping plant louse, Cacopsylla melanoneura (although there are several virtually identical species). It's very common everywhere, and lives mostly on hawthorn during the summer, migrating onto conifers when the leaves fall. For something 3 mm long, it's incredibly hardy.

For all you gardeners, here's an aphid. Not your typical greenfly, this is the Cypress Aphid, Cinara cupressae, which is a specialist that sucks the juice of Leyland Cypress. It was a concern for a while that this would decimate hedgerows across the country when it arrived in the UK, but that doesn't seem to be happening. Perhaps it doesn't like the climate...

For a bit more glamour, this was a beauty. Getting on for a centimetre long with that impressive ovipositor, it's some sort of ichneumonid wasp. I'm not going to even attempt to get further than that, as there are far too many species of wasps in Briatin, and most of them need to be dissected to tell them apart - or at least looked at by a specialist with a big microscope. You have to wonder what it's parasitising at this time of year, or whether it's just trying to survive the winter. A curiosity of this one is that the ovipositor appears to be hairy. That's just weird... how does it stick it into its victim?

One wasp is never enough, of course, so here's another. This is a little chalcid, barely 3 mm long, and like most chalcids, it's metallic. Not just metallic-looking, I hasten to add, but truly metallic - that cuticle is reinforced with zinc (or manganese, depending on the family). Stunning little creatures when you get the light right - I didn't, quite.

   Finally, how about this?

What on earth is a little squishy caterpillar doing out in this weather? It's presumably from some sort of small moth, but you'd think evolution would be kinder to it.

I'm not entirely sure how these creatures cope with the cold. Water of course freezes at 0C, but with all the various organic bits in, it will be a bit colder before critters like these go solid. I'm sure -12 would do it, though. There are various creatures, including fish, that have evolved anti-freeze in their tissues, and there's a bit of a summary here:

http://en.wikipedia.org/wiki/Antifreeze_protein

Nature never ceases to amaze me... and it's all to make sure we don't get bored in the winter. :)

So why sponges?

I suppose now is as good a time as any to introduce you to the marvellous, magical things we call sponges. For one thing, it gets me away from the packing, plus I've not written any fantasy for ages. [Actually, I'll only make up one thing - see if you can spot it.*] First off, there's a lot more to sponges than meets the bathroom. They include crawling species, shape-changers, predators, and quite possibly the oldest living individuals on the planet. They also go back in history a very long way, which is rather handy from my point of view. The general view among biologists and palaeontologists now is that sponges either are our earliest animal ancestors, or they evolved directly from them.

Lucy meets a distant relative

The textbooks will tell you (as will Sir David Attenborough in his latest series) that sponges are pretty dull things, little more than collections of single-celled choanoflagellates stuck together. The thing is, though, they've been evolving for just as long as we have, and that view really does them a disservice. They may not have brains and nervous systems, but they've evolved ways around it - many glass sponges have electrical ion channels instead, and other groups have complex internal chemical signalling processes. They also have very interesting immune systems, which can respond to invasion in a more subtle range of ways than can, say, a tarantula. In other words, if they're bundles of cells stuck together, then they've stuck in a very intricate way. 

A typical sponge? Note the chimneys (exhalent canals) and small pores (inhalent canals).

Fundamentally, though, a sponge is a living sieve. It's a body with pores all over it, leading to canals that join together, eventually leading to one or more large holes at the top. The canals are lined with cells that have little whip-like flagellae, which all beat in the same direction to suck water in through the pores, and spit it out at the top. Sponges may not have organs, it's true. But they do have a surprising array of different cell types. Some of them create currents and catch food, others are for oxygen exchange, others for secreting the skeleton, others for reproduction and so on. Some of them, the archaeocytes, can become any other type - a very neat trick similar to the stem cells so beloved of modern medicine.

The organic (collagenous/chitinous) skeleton of a modern "bath sponge"

I mentioned a skeleton, and here's the one of  a typical bath sponge. It's made of collagen fibres forming a network, and this supports the sponge's soft tissues. However... it's not normal. Most sponges have a skeleton made of interwoven or fused spicules of either opal-A (amorphous silica, similar to quartz, similar to glass, but not quite either) or calcium carbonate (calcite). This is a bit of the skeleton of Euplectella ("Venus' Flower Basket") - it's an amazingly exquisite construction of rods and cross-shaped spicules woven together:

This file is licensed under the Creative Commons Attribution-Share Alike 2.5 Generic license

To finish off for the moment, if you want to really follow my sponge posts in future, remember these three major groups. A big chunk of early sponge fossil research is about how they're related.

Hexactinellida ("glass sponges" with siliceous, often cross-shaped spicules)

Demospongea ("common sponges", with siliceous calthrops- or rod-shaped spicules, or an organic skeleton, or no skeleton at all)

Calcarea (calcareous sponges, with a skeleton of calcite spicules).

Next time I get bored, I'll get onto the fossil record of these wonderful beasties. Toodle-pip!

[*Actually none of it was made up. There really are predatory sponges like Asbestopluma that eat crustaceans, many sponges crawl (slowly) by reorbing some bits of themselves and growing in others, and some of the really big Antarctic sponges are thought to be over 10,000 years old - although proving it is complicated, which is probably why I've only ever seen it at a conference as yet...] 

Huddersfield in snow

On Friday we went for a walk along Kilner Bank, a sort-of nature reserve in Huddersfield not far from where we live. We tend to walk along there quite a lot, often looking for bugs. There are a variety of habitats, including conifers and grassland We've also been involved with the Kilner Bank Improvement Group, which has done a lot of good work cleaning up the bank and encouraging wildlife.

This was the snowy scene walking along the road:

And a rose bush with snow on.

Nice view of Huddersfield, just as it was getting dark.

Very cold worms

As Lucy says, the happy expression in the previous post was well justified. As it happens, that particular moment might have had more to do with suddenly being able to feel my toes again (it's a grimace with frostbite, honestly), but the principle works.

It turns out that reports of whole sponges were entirely accurate, and strange things they were too. The first sign was bubbly black markings in the mudstone that stand out much better when wet (convenient, that). We've not yet found a whole one, but I reckon the entire thing was probably a good 10 cm long... which for the earliest Ordovician (Tremadoc) is quite unusual. The black preservation is some oxidation product of pyrite (we found one or two fresh ones as well).

There were other sponges as well, including this amazing little thing, a mere centimetre or so across. The stalk is like nothing I've ever seen on a fossil before, although I'm sure there are some recent ones that are fairly similar...

Following our adventures with worms in Mid Wales the past couple of years, where the fabulous little beasties known as palaeoscolecids turn out to be rather common, we were half expecting to find more of the same. As a reward for being mad enough to go out in the aforementioned weather, the gods of fossils let us have some. Well, at least one definitive one... plus lots of others that might be, but without such obvious, enormous plates. Since the worm is 1 mm diamater, those nice obvious plates must be a good 30-40 microns across...

The object of this trip was to investigate a possible field site for our reseach over the next couple of years. I reckon it passes the test... we can't wait to get back.

Arenig Fawr

Last week we went on fieldwork to North Wales, to the Tremadoc of Arenig Fawr, to be exact. Rumours of complete sponges and possible worms can't be ignored! With unerring timing, we picked the weekend with snow. Deep snow. The sort of snow you don't expect in Wales, in November. The mountain looked like this:

The rocks looked like this:

And Joe looked like this:

The happy expression is due to finding sponges, worms and some other interesting bits and pieces.


Thanks are due to Chris, Naomi and Neil, for coming in the first place and not complaining about the cold!