Talk:Kimberella

Classification problem
The second sentence in the Classification section says, "The first specimens discovered, in Australia in 1959, were originally interpreted as box jellyfish by Martin Glaessner and Mary Wade in 1966,[5] and then as box jellyfish by Wade in 1972." I presume from the opening paragraph and an edit summary that it should read, "The first specimens discovered, in Australia in 1959, were originally interpreted as a jellyfish by Martin Glaessner and Mary Wade in 1966,[5] and then as a box jellyfish by Wade in 1972", but I don't have access to the cited source. -- Donald Albury 13:18, 12 July 2008 (UTC)


 * Oops! Thank you! -- Philcha (talk) 13:43, 12 July 2008 (UTC)

Discovery reference
In Glaessner, Martin and Daily, B. (1959). 'The Geology and Late Precambrian Fauna of the Ediacara Fossil Reserve'. Records of the South Australian Museum 13: 369–401, there is no actual mention of the Kimberella name, but it appears to be illustrated as an unknown form in figure 9. Can any one find the article where Kimberella was first described, presumably one with authors Glaessner, and Daily; without Martin? Graeme Bartlett (talk) 23:37, 14 July 2008 (UTC)
 * Fedonkin et al (1997) says Glaessner & Wade (1966) classified it as a jellyfish — I have to take Fenokin's word, as I don't have access to Glaessner & Wade (1966), as G & W 1966 is not accessible on the web, not even via JSTOR. The point you spotted about Glaessner et al (1959) is why Kimberella avoids the word "described", which often means "... in enough detail to offer a classification, and then name it". Philcha (talk) 07:47, 15 July 2008 (UTC)
 * A couple of libraries in my city should have Glaessner & Wade (1966), so I will look it up eventually to confirm. Graeme Bartlett (talk) 06:01, 21 July 2008 (UTC)
 * You can save your legs – it's available free online. I've now linked it in the article (-: Martin  (Smith609 – Talk)  07:10, 21 July 2008 (UTC)


 * Thanks!
 * But I've just noticed that Glaessner & Wade (1966) appears to refer to it as Kimberia quadrata in the list of Medusoids at the end. Any idea when and why the name changed? If so, I suugest it could go in "Classification". -- Philcha (talk) 07:54, 21 July 2008 (UTC)


 * The name had already been assigned to a turtle "by Cotton and Woods (1935)", and was thus invalid. Back before the internet it often took quite a while for duplicate names to surface! There's only one article mentioning both terms, which I guess is an uninteresting comment stating the necessary name change, but I don't think I have access to it. Martin  (Smith609 – Talk)  16:51, 21 July 2008 (UTC)

Protostome explanation
Hi,

While the explanation of the protostome/deuterostome distinction is a good one, I'm not sure that this article is the place to make it. The significance of Kimberella's protostome affinity is that two major animal lineages had diverged before the Cambrian period - it is of little significance what the defining features of those lineages are, especially as none of these features are seen in Kimberella. I'm not even sure that we need to explicitly mention the terms "protostome" or "deuterostome"!

Martin  (Smith609 – Talk)  14:01, 15 July 2008 (UTC)


 * In terms of logic I suspect you're right, but the source (Erwin 2002) talks about the protostome/deuterostome divergence. -- Philcha (talk) 22:00, 15 July 2008 (UTC)


 * Yes, but we can talk about "the divergence between two major, derived clades of animals", and the significance that such a divergence should have taken place before the start of the Cambrian, without using the names of the clades - which attach an undue significance to the symptom they describe. I think we need to be careful not to confuse etymology with meaning; we don't describe the meaning of the word "mammal", or the features that unite mammals, each time the clade pops up; nor should we feel obliged to do so with less familiar groups. Martin  (Smith609 – Talk)  22:09, 15 July 2008 (UTC)


 * How does this re-write grab you: to replace the second two paragraphs of the "Theoretical importance" section. Feel free to amend it as you wish.

Much of the debate about the explosion centres on the rapid rate of diversification, because the fossil record of pre-Cambrian metazoans is so sparse. Animals more complex than jellyfish and their cnidarian cousins are split into two groups, named the protostomes and deuterostomes. The molluscan affinity of Kimberella strongly suggests that it was a member of one of these groups, the protostomes. If so, this means that the protostome and deuterostome lineages must have split some time before the 558- million year old beds bearing Kimberella, and the cnidarians earlier still. This would suggest that much of the diversification attributed to the "Cambrian explosion" had in fact occurred before the start of the Cambrian period.


 * The GA reviewer insists that if the article uses "protostome" or "deuterostome" it should provide a short definition. I sympathise with that view, although finding a good source to support an informative definition was difficult (see  my grumbles).


 * But if we avoid using "protostome" or "deuterostome", all that's left in Erwin 2002 is the argument that crown-group Cnidaria were around earlier and hence the Cnidaria-Bilateria split must have been even earlier -- i.e. Kimberella is not a player and the section "Theoretical importance" might as well be deleted. -- Philcha (talk) 16:30, 16 July 2008 (UTC)
 * This is more or less what I was looking for with proto/deutero. It doesn't really explain what they are, but it explains what the reader needs to know to understand the article, which is what matters.  Some clunky language (i.e. "Molluscan affinity") to polish, but nothing major.  SDY (talk) 16:36, 16 July 2008 (UTC)


 * I've edited in wording based on the above but modified to avoid the complexities of bilaterian / protostome / deuterostome evolution from presumed proto-Cnidarians and to stick closer to what Erwin 2002 says. -- Philcha (talk) 17:36, 16 July 2008 (UTC)


 * I'm not sure what bearing Kimberella has on the cnidarian/bilaterian split, which I note you've retained. If we mention that, we really need to explain that bilaterian == (deuterostome + protostome), which is (in my opinion) more unnecessary prose.  Do you think we could get away with chopping that last sentence? Martin  (Smith609 – Talk)  19:09, 16 July 2008 (UTC)
 * The refs say it was a bilaterian, and I think we should leave it at that. I know that conventionally bilaterian == (deuterostome + protostome). But while hunting for an informative definition of "protostome" with WP:RS, which is now in Protostome (surprise!), I found hints that it may not be that simple. Some time when I know a lot more invertebrate palaeo and am too drunk to have any sense at all I'll have a go at the origin of bilaterians / protostomes / deuterostomes, which I suspect is a real can of Chaetognaths. -- Philcha (talk) 21:28, 16 July 2008 (UTC)
 * I've made a minor tweak, and I think I'm happy with it as it stands now - if you are? Otherwise, while it could still benefit from a bit of tidying, for me the article's well into the domain of "good enough"! Martin  (Smith609 – Talk)  21:42, 16 July 2008 (UTC)
 * Masterly phrasing! -- Philcha (talk) 21:57, 16 July 2008 (UTC)

As the reviewer noted, the evidence that Kimberella seems to provide for the diversification of animal life well before the 'Cambrian explosion' increases its notability. If we ignore that, Kimberella sinks down to being just another fossil. -- Donald Albury 19:16, 16 July 2008 (UTC)
 * I'd hoped that the current description of its role in dating the protostome/deuterostome split would cover that point - perhaps not? Martin  (Smith609 – Talk)  19:23, 16 July 2008 (UTC)

"Last putative Ediacaran"
What is this "last putative Ediacaran" which the timeline speaks of? Martin  (Smith609 – Talk)  16:41, 15 July 2008 (UTC)


 * The same one as at Ediacara biota. Could it be Hagadorn's alleged Californian Swartpuntia? -- Philcha (talk) 19:25, 15 July 2008 (UTC)


 * That rings a very vague bell... gosh, it's a long time since I was involved in that article! Which reminds me, was there a problem with adapting the template-based graphical timeline for use in this article, instead of the hard-to-scale-and-update-but-nonetheless-very-ingenious annotated image? Martin  (Smith609 – Talk)  19:40, 15 July 2008 (UTC)


 * Yes. I thought I'd left you a message about that as well as Microbial mat, but it looks like I had a mental lapse. The timeline version is at User:Philcha/Sandbox. The GA reviewer said it went pear-shaped in IE and Firefox. I've been using K-meleon (another Gecko browser) recently, for reasons that I can't remember. It looks OK in K-meleon - until I use CTRL+ to up the font size, when it goes pear-shaped. I suspect it's a matter of various browsers' different default stylesheets.
 * Is "hard-to-scale-and-update-but-nonetheless-very-ingenious" a member of the class of classes that are members of themselves? -- Philcha (talk) 21:11, 15 July 2008 (UTC)


 * It looks fine to me in both IE and Firefox, scaling and all. Maybe said reviewer would be able to detail the problems so I could try to fix it?  Do the timelines at, say, Devonian display alright? Martin  (Smith609 – Talk)  21:21, 15 July 2008 (UTC)


 * You were looking the version in my sandbox, weren't you? I certainly got from that version the symptoms I described. You could ask the reviewer, SDY -- if you do, please remind him that the patient is now in quarantine at User:Philcha/Sandbox. -- Philcha (talk) 21:57, 15 July 2008 (UTC)


 * It looks fine to me in the sandbox, but it was being very funky in the article, with the captions overlaying the main text of the article. SDY (talk) 23:49, 15 July 2008 (UTC)


 * I was. Are the symptoms still there?  Zooming is implemented differently in different browsers (grr), maybe that's the source of your problems. Martin  (Smith609 – Talk)  22:12, 15 July 2008 (UTC)
 * Re "different browsers (grr)", thank your lucky stars you've never had to worry about Netscape 4.
 * Yes, even in K-meleon if I use CTRL+ to increase font size, the notes jump out of the container and spill lower down the page.
 * Note that the problem arose when I tried to squeeze the width of the timeline by wrapping a fixed-width DIV with style="width:250px" round it, as the default width was too much considering that there an infobox and image on the right as well. The version at Ediacara biota behaves nicely when I use CTRL+. -- Philcha (talk) 22:46, 15 July 2008 (UTC)


 * Ah! Well that would explain it. That should be rather easily fixed, I hope... let me tinker! Martin  (Smith609 – Talk)  22:53, 15 July 2008 (UTC)

Doushantuo
Does the Doushantuo formation really span that length of time? Its article doesn't seem to think so; either that or the timeline is quite wide of the mark. Martin  (Smith609 – Talk)  21:30, 16 July 2008 (UTC)


 * It surprised me too, but that's the range given by U-Pb Ages from the Neoproterozoic Doushantuo Formation, China, which is cited in Doushantuo formation. Perhaps the problem is that the formation has a long time span but fossils have only been found (so far) in a small part which is "poorly constrained". -- Philcha (talk) 10:17, 18 July 2008 (UTC)

Reference trouble.
There are a couple of confusing or confused references, namely, those presently labeled [3] and [9], the reference and, respectively. Both seem to refer to the same 23 pages long article. Both also link to the same 5 pages long preprint, which also has the same title as the article.

I have not (yet) succeeded to access the article, but I read the short preprint. The referred claims I was looking for were not in any way supported by the content of that preprint. I looked for support of the following claims about ecology and reproduction methods, in the section that read


 * Ecology Kimberella dwelt in shallow waters (up to tens of meters in depth), sharing the calm, well-oxygenated sea floor with photosynthetic organisms and microbial mats. Assemblages bearing Kimberella often also bear fossils of Yorgia, Dickinsonia, Tribrachidium and Charniodiscus, suggesting that it lived alongside these organisms. Kimberella probably grazed on microbial mats, but a selective predatory habit cannot be ruled out. Fedonkin reckons that as it ate, it moved "backwards"; the trail thus created was destroyed by the subsequent grazing activity. Conversely, Gehling et al. claim that it moved 'forwards'.  Fans of grooves are often found radiating from the "head" end of the organism; these indicate that the organism stayed in one place, and raked the surface of the microbial mat towards it by extension of its head, which bore two "teeth".[another reference] Gehling et al. reconstruct Kimberella as having a long neck that operated like the arm of a digger, rotating about an axis perpendicular to the sea floor in order to produce the sweep of the fan, and rotating towards and away from the animal to scrape food from the substrate to the mouth. The lack of evidence to the contrary suggests that the organisms reproduced sexually. The waters in which Kimberella dwelt were occasionally disturbed by sandy currents, caused when sediments were whipped up by storms or meltwater discharge, and washed over the creatures. In response to this stress, the organisms appear to have retracted their soft parts into their shells; apparently they could not move fast enough to outrun the currents. Some organisms survived the current, and attempted to burrow out of the sand that had been deposited above them; some unsuccessful attempts can be seen where juveniles were fossilised at the end of a burrow a few centimetres long.

Actually, only the reference about a retrograde movement while feeding seems to be directly supported by that preprint. My guess is that this preprint only comprises parts of the published article text. Alternatively, there may be a confusion of sources; there are several other references to Fedonkin articles. In any case, I do not doubt most claims (although the idea that these professionals would assume a sexual reproduction only based on lack of evidence in either direction is a bit strange); and they might be supported by the full article. Thus, I'll tag the section with some mental reservations about the tag being inadequate. JoergenB (talk) 20:40, 17 December 2016 (UTC)


 * The whole article is 23 pages long. On page 177 it states this: "No specimens of Kimberella have been found undergoing any kind of asexual reproduction such as fission or budding; it seems, therefore, that it must have reproduced sexually" which sounds definite enough to use. Page 158 mentions shallow and well aerated, and tens of meters, in the photic-zone. The other fossils are there but also including Andiva. The article talks about crawling backwards. It talks about retraction when buried by sediment, and outrunning, and burrow out attempts where the big ones escaped, but juveniles got stuck. The bit about meltwater seems to be made up, as the article says turbidity current, but does mention storms. So all except for one word pans out in the ref. But the problem of the duplicated references, and partial pdf remains. Graeme Bartlett (talk) 12:48, 18 December 2016 (UTC)
 * OK; thanks! The reference seems clear enough.  (I still find their conclusion about the reproduction slightly surprising; couldn't you equally well argue that "as no specimens of Kimberella have been found with signs of a sexual reproduction mode, such as discernible gonads or eggs, seemingly it must have reproduced asexually"?  However, of course, the conclusions by the leading experts indeed is what we should include in the article.)
 * It would be interesting to read the whole article. Our university ought to have access to it, in some way, I guess.
 * Do you think we could just merge the two references, by replacing one with the other? JoergenB (talk) 03:29, 25 December 2016 (UTC)
 * We should certainly merge those references. Email me if you want to see the whole article. Merry Christmas. Graeme Bartlett (talk) 03:59, 25 December 2016 (UTC)

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new species
could we maybe add a little section about the new species?--Paleofroggy (talk) 22:25, 17 May 2019 (UTC)