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Post by Joe Botting on Apr 29, 2014 13:53:32 GMT -5
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Post by reighan on Apr 29, 2014 15:33:02 GMT -5
(Get a bigger one!) Congratulations. :-)
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Post by pleecan (Peter Lee) on Apr 30, 2014 10:10:47 GMT -5
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Post by Joe Botting on Apr 30, 2014 15:45:31 GMT -5
Thank you both. It doesn't seem to be making the mainstream, unfortunately - no BBC reports, alas... yet. Thanks for FBing it, Peter.
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Post by pleecan (Peter Lee) on Apr 30, 2014 17:30:30 GMT -5
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Post by pleecan (Peter Lee) on Apr 30, 2014 17:32:00 GMT -5
Giving the early fossil record of sponges a squeeze
Jonathan B. Antcliffe1,2,*, Richard H. T. Callow3 and Martin D. Brasier4,5
Article first published online: 29 APR 2014
DOI: 10.1111/brv.12090
onlinelibrary.wiley.com/doi/10.1111/brv.12090/abstract
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Post by Joe Botting on May 6, 2014 14:39:35 GMT -5
I've been waiting for that paper to come out for ages, Peter, so many thanks for the link. Now I'm waiting for Jon to send me a pdf of it...
I should probably say that I agree completely with the conclusions - there are basically no reliable Precambrian sponge records at all. That is, you might say, rather curious.
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Post by pleecan (Peter Lee) on May 12, 2014 6:51:38 GMT -5
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ryanc
New Member
Posts: 15
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Post by ryanc on Jul 24, 2014 15:48:30 GMT -5
How could sponges have been so remarkably complex so very early on? Do you think it's likely that life started somewhat earlier than we currently think or that multi celled organisms arose earlier?
I wonder what the common ancestor of the sponges and corals looked like and if any fossils of them exist...
Any thoughts on why sponges became less complex later on - presumably it was more efficient to ditch certain traits?
It's a thought provoking paper that's for sure - how has it gone down amongst the scientific community?
Regards,
Ryan
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Post by ammocarbsteve on Jul 24, 2014 23:37:37 GMT -5
Congratulaions Joe.....
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tqb
Enthusiastic fossilologist
Posts: 111
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Post by tqb on Aug 5, 2014 11:31:45 GMT -5
Lovely stuff - just been reading Erwin & Valentine, "The Cambrian Explosion" - it's not that old (2013) but it's nice that this puts a chunk of it out of date!
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Post by reighan on Aug 6, 2014 11:03:34 GMT -5
Yes, nice! Actually, I love that whole slab. :-)
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Post by Joe Botting on Aug 21, 2014 14:51:24 GMT -5
Hi Folks, It's amazing how you miss a computer when it dies... I had an enforced couple of weeks off, and have been trying to catch up since then, so it's good to see so much activity now I'm back! Ryan, some interesting questions there - thanks. I'll see what I can do with them, but there are lots of unanswered questions... 1. It depends what you mean by very early on... what we seem to be finding now is that all the Precambrian records of sponges are extremely dodgy or just plain wrong, which puts sponges in the same category as the other animal phyla - appearing some time around or shortly before the base of the Cambrian. My feeling is that this is genuine: sponges and cnidarians separated and diversified at the same time, and it wasn't all that long before the Cambrian boundary. 2. I'd love to know that too. Aside from being kind-of vase-shaped, and tetraradially symmetric ( ), it's hard to say. Did it have tentacles, or feed by osmosis? I do wonder whether archaeocyathans might have something to say about the origins of both groups, since although they're almost invariably lumped in with sponges now, there's actually no direct evidence for that. If they were sponges, it's hard to see which of the known ones they were closest to (although that's true whatever their relatives were). There are also these things, which might possibly be of interest: www.nature.com/ncomms/journal/v2/n8/full/ncomms1457.html but until we get something that looks like an Ediacaran sponge with tentacles, we're likely to be guessing. 3. Simplification: it's actually pretty common when things adopt a sessile lifestyle with simple behaviour - take a look at sea squirts, for example, and concentricyloids (starfish that have lost most or all of their digestive system). Having clear symmetry for sponges would have been a disadvantage, as it limits your flexibility during growth - especially in shallow, turbulent conditions. Adopting that sort of lifestyle would also render any rudimentary muscle tissue or nervous system largely redundant (although sponges do use a slow, chemical-signal or electrical impulse replacement, so if they originally had nerves then the loss is a strange one). It's worth noting that their only real predators today are sea slugs, which probably didn't appear until relatively late (perhaps Mesozoic, but there is zero fossil record). If they had virtually no predators in the Cambrian and Ordovician then perhaps there was not much pressure for adapting anything except passive defence mechanisms (spicules and chemicals). And, of course, you're surely right about the efficiency. As for how it's gone down... interestingly! So far no-one has cited it, but that will take a while. The general response seems to be, "What on Earth am I meant to do with this?!?"
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ryanc
New Member
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Post by ryanc on Aug 21, 2014 17:18:14 GMT -5
Hi Joe, Thanks for taking the time to answer my questions - I warn you I have about a million more though I love how the Chinese material is really shaking up the science of palaeontology in so many different areas - exciting times! Regards, Ryan
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Post by Joe Botting on Aug 22, 2014 14:58:29 GMT -5
No worries, Ryan - I like questions, at least when I've got time to answer them! Keep 'em coming... :-D
Yes, the Chinese rocks are producing a lot of strange things right now, but to be honest, it's probably got as much to do with how many resources are being funnelled into finding them as it has to do with their riches being better than anywhere else...
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