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Tuesday, 15 December 2015

Just When You Thought It Was Safe…


Ichnofossils

Okay folks, that’s our challenge for today. Somehow we’ve got to find our way down there and try to descend once more into the valley. But before we go haring off to find the possible route of descent I’ve just noticed a bit of stone that looks somewhat intriguing. As you can see there are dark patches running through it and if you look closely you can see that they are radiating outwards from a common point below the stone. Take a closer look under the hand lens. There are faint tracks showing that the structure is branched and some clusters of dots, some of which are in pairs.  Both of these tell a story of burrowing creatures on the sea bed in the geological past and it introduces us to the little known science of ichnology1. Just as historians can piece together a story from ancient human artefacts, ichnologists study these trace fossils, or ichnofossils as they are technically known, to build up a picture of the creatures that made them. Fascinating forensics if you’re looking for a new hobby and serves to remind us that the landscape we’re walking through has a long and detailed history. We’ll leave it somewhere conspicuous and pick it up on the way back. The descent is going to be tricky enough without carrying bloomin’ great rocks around with us.

Sage galls and wasp, Cynipidae
Here we go then, but on your trip down have a look in the sage bushes on the way and see if you can find some galls. I read something the other day which I want us to check out. This is the Greek Sage, Salvia fruticosa, and some years back I was given some “sage berries” by a neighbour as a local delicacy. At the time I didn’t realise that I was eating insects (and neither, I suspect, did they). Anyhow, back in Israel in 2001 it was discovered that these particular “berries” were galls produced by a new species of Cynipid gall wasp2. Now, I’ve noticed over the past couple of weeks that there seem to be two different types of gall: one which is produced from the side of the stem and one which is produced at the tip. The question is: are they produced by the same species of wasp or from two different species? Ah, well done, you’ve found some tip types, with and without exit holes. We’ll have a look at them under the microscope later and meanwhile, we’ll keep our eyes peeled for the other type. Incidentally, eating insects as a method of feeding the world is a bit of a hot topic at the moment. A good idea do you reckon or just another way of destroying the planet’s biodiversity?




Scorpion, Mesobuthus and Scorpius constellation
We’ve reached a thirty foot vertical drop which will restrict our downward progress somewhat. Never mind, we’ll go back a bit and try to get around. However there’s a nice fallen pine here in a state of decay so let’s probe the depths and see who’s about. That’s rather a nice scorpion you’ve found there, somewhat larger than the small wood scorpions we’ve been seeing recently. Now I know that I said “There are only about two dozen or so potentially lethal scorpion species out of the fifteen hundred or so that are known to science and, as far as I know, none of them live on Crete.” – (See The Misty Thripti Mountains ) but I’m not sure that this one has been recorded on Crete before. It’s a Mesobuthus, a genus that contains some very venomous species. I’ll just take that piece of wood from you and put him back. Seeing him in that position reminds me; the constellation Scorpius is very easy to recognize at this time of year. If you look to the south for the red star Antares the shape of the scorpion really does look like the one you just found. Well yes, I quite understand, it probably won’t be the last thing you want to look at before you go to bed tonight.


Galatella cretica
How about looking at some pretty flowers by way of something different? I mentioned these Galatella in passing a couple of weeks ago but they’re really in bloom right now and I love the way that they change colour from a pale green to golden yellow and then a deep magenta. The one colour that they aren’t is white which is strange for a plant who’s name begins with ‘gala’ as this is the Greek for milk. I wonder if it’s a diminutive of Galatea, the sea nymph who was in love with Acis and turned him into a river spirit after the jealous Cyclops, Polyphemus, chucked a boulder at him? Even so Galatea still means ‘she who is milk white’ which doesn’t really fit with the flower colour. 

Crag Martins, Ptyonopogne rupestris
We seem to have come full circle and it’s pretty evident that we’re not going to get back down into the valley from this side. Still, we’ll pick up our trace fossil and try from the other side next week. Hang on though, what are those flitting about behind the car? Well I’m blowed – do you remember that patch of mud we drove through just before we parked up? It seems we must have churned it up enough to be useful to a flock of Crag Martins. A few weeks back English twitchers were hammering up and down the motorways to get a glimpse of one of these birds and we’ve got a couple of dozen of them right here. It’s surely too early for breeding but crag martins reuse their nests each year so maybe they’re doing a bit of winter maintenance whilst the materials are available. Could be they even use them as bad weather roosts when the storms hit? As always there are many more questions than answers.
Until next week then – Happy hunting.


1With thanks to Mike Hardman and Dr T via the Natural History Museum, London for identification of the trace fossils as Chondrites, Arenicolites or Diplocraterion and other ichnogenera.



See all the pictures including insets in detail on Flickr



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LINKS:
Naturalists (the facebook page that accompanies this blog)




 

5 comments:

  1. While you are walking in the sun we've been traipsing through glutinous mud and found something I'd have loved to show you, if only I'd had a camera with me. A tree had fallen across our path and split open to reveal what looked like honey combs. There were a couple of holes in the trunk that seemed as if woody woodpecker had been drilling. At the tree's base were several 'shelves' of fungi. BFN x

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    1. Sounds intriguing. have a lovely Christmas Yvonne and regards to Alan.

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  2. Scorpius was a magnificent sight from Spetses I remember - from the UK the sting part is below the horizon. Probably Orion's only rival as the greatest constellation of the night sky, appropriately enough

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    1. I think that The Plough (US Big Dipper) may vie for that title Simon. It was the first one that I was taught as a child.

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  3. I'm such a chicken. When I saw the scorpion, I would have been out of there! OTOH, I would have loved to have made that trip with you.

    We have a very interesting situation with fossils near me. I must take some photos and send them to you. In eastern Virginia, USA is the James River. (People know the James River because of the Disney movie Pocahontas, which isn't accurate history!) But the banks of that river are nothing but fossilized shells and remnants of sea life.

    Isn't nature fascinating?

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