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Post by Joe Botting on Apr 2, 2013 4:37:27 GMT -5
We've been looking at a new site: a recently-dug farm quarry that exposes about 14 m of what seems to be the boundary between the Middle and Upper Ordovician. It's a general mish-mash of siltstones, but has a really diverse graptolite fauna, together with lesser trilobites, the normal brachies, and so on. Parts of the section are also packed full of sponges. Badly preserved, yes, but that's largely due to the weathering. Some of them have spicules preserved nicely, but they're so tiny I don't think my camera will be able to show them. I'll have a go at some point, though. In the meantime, here's a little something that has turned up: another carpoid. This is an example of the cornute Galliaecystis, which seems to be very widespread in the Builth Inlier mudstones.  Galliaecystis sp. by joe with a camera, on Flickr It's a baby one, and some it is on the counterpart, but what you can see as a narrow L-shaped body is pretty much the margin. It's not U-shaped, as the common ones are at Bailey Einon. There are also large petaloid cover plates coming off the aulacophore (feeding arm at bottom), which is rather unusual too. Basically, it looks to me like this is a different species. Which would be nice. The first ones are being written up at the moment, but this does tend to complicate matters... ;D |
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Post by ammocarbsteve on Apr 2, 2013 5:17:21 GMT -5
Joe... That's fabulous... potentially a new species to boot... A new exposure hmm... What vehicle have you purchased to get around now your back a JCB?...
on a serious note... How would this discovery affect the write up of the previous...Can you incorporate this discovery into that and model your theories around this or would it have to be written up seperately and then a comparison made at a later date...
Interesting stuff... Well done....
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Post by Joe Botting on Apr 2, 2013 6:23:48 GMT -5
Thanks Steve... JCB... don't tempt me. Actually, though, this is all in walking distance - bliss.
As for the comparison with previous material, well, it gets complicated. We've got a bit of disagreement over how many "Galliaecystsis" species there are in the area: one with a lot of variation at different growth stages, or at least two. For it to all be one, there would need to be a switch from U-shaped at early stages to broadly boot-shaped later. This one is among the smallest we've seen, seems to rule out the option of them starting U-shaped... so I think this is pretty strong evidence that there are at least two species in our previous material, and this is a third. Whether Bertrand will want to take it into account for the first paper, or have this as a separate addition, I'm not sure. He may also argue that it's all one species that is just very morphologically variable.
What this means for wider implications is hard to say, with such a rare group. The question really is whether the area was colonised by a single species that ended up living practically everywhere in the central Welsh Basin at this time, or whether the family (Hanusiidae) was undergoing an active diversification. We've also got the mitrate Anatifopsis (who knows how many species? It's hard to tell them apart, if there was more than one) and an undescribed solutan, so there was something going on. As always, getting the taxonomy right does have all sorts of implications further down the line...
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Post by pleecan (Peter Lee) on Apr 2, 2013 7:25:51 GMT -5
Very nice Joe congratulations on the find .... Nikon D80 ... get youself a copy stand to mount your camera.... a lab jack for specimen... coarse focus... lens wise.. get an adapter Nikon to M42 lens mount now you have cheap access to thousands of high quality lens.... M42 bellow sub $100 or a bunch of extension tubes. Try Pentax Takumar 50mm .... very sharp...
PL
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Post by ammocarbsteve on Apr 5, 2013 1:53:34 GMT -5
Joe... Thanks for the explanation... morphologically variable sounds the easy answer but I suppose given the extent of time periods sometimes represented by these individual layers it can make a lot of sense to allow for this....
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Post by Joe Botting on Apr 5, 2013 16:10:53 GMT -5
Thanks for the tips, Peter - if I get a job I might be able to think about following them up...  Still, I've had a bit of practice with the set-up I've got, so it'll do for now. Anyway, here's a sponge from the new site. It's not very finely preserved and you can see it's difficult to make out the skeletal arrangement. The good news is that there are a lot of specimens, so it ought to be possible to piece this fauna together eventually... if I can tell which are actually the same species...  undescribed sponge by joe with a camera, on Flickr By comparison, here are some specimens of Cyathophycus loydelli that we picked up the other day. In these yuo can see the regular skeletal grid very clearly (and there's a lot of fine detail under the microscope too).  Cyathophycus loydelli by joe with a camera, on Flickr Steve... yes, you're right that intraspecific variation has to be considered, and it's surprising how much of it there is. What you look for are gaps in the continuum, to show that it's not just a simpole variable (like height in humans). If there's a whole spectrum of variation between the end-members then yes, better call it the same thing. If not, then it looks like they're really separable. Theoretically. Just don't think about differences between, for example, males and females...  |
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Post by ammocarbsteve on Apr 6, 2013 2:06:37 GMT -5
Joe...Great sponges... I can see they will take some interpretation to iron out the species...
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Post by pleecan (Peter Lee) on Apr 6, 2013 10:47:48 GMT -5
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Still, I've had a bit of practice with the set-up I've got, so it'll do for now. 