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The dorsal sclierete spikes look a little like 'morphed' versions, of the lateral 'side plates', on Anomalocaris & Opabinia. —Preceding unsigned comment added by 66.235.26.150 ( talk) 18:40, 1 March 2011 (UTC)
Wiwaxia, found so far only in the Burgess Shale, had chitinous armor consisting of long vertical spines and short overlapping horizontal spines. It also had what looked like a radula (chitinous toothed “tongue”), a feature which is otherwise only known in molluscs. Some researchers think the pattern of its scales links its closely to the annelids (worms) or more specifically to the polychaetes (“many bristles”; marine annelids with leg-like appendages); but others disagree. [1] [2]
Orthrozanclus, also discovered in the Burgess Shale, had long spines like those of the wiwaxiids, and small armor plates plus a cap of shell at the front end like those of the halkieriids. The scientists who described it say it may have been closely related to the halkieriids and the wiwaxiids. [3]
Halkieria resembled a rather long slug, but had a small cap of shell at each end and overlapping armor plates covering the rest of its upper surface – the shell caps and armor plates were made of calcium carbonate. Its fossils are found on almost every continent in early to mid Cambrian deposits, and the “small shelly fauna” deposits contain many fragments which are now recognized as parts of Halkieria’s armor. Some researchers have suggested that halkieriids were closely related to the ancestors of brachiopods (the structure of halkieriids' front and rear shell caps resembles that of brachiopod shells) and to the wiwaxiids (the pattern of the scale armor over most of their bodies is very similar). [4] Others think the halkieriids are closely related to molluscs and have a particularly strong resemblance to chitons. [5]
Odontogriphus is known from almost 200 specimens in the Burgess Shale. It was a flattened bilaterian up to 12 cm (5 in) long, oval in shape, with a ventral U-shaped mouth surrounded by small protrusions. The most recently found specimens are very well preserved and show what may be a radula, which led those who described these specimens to propose that it was a mollusc. [6] But others disputed the finding of a radula and suggested Odontogriphus was a jawed segmented worm belonging to the Lophotrochozoa (a “super-phylum” which contains the annelids, brachiopods, molluscs and all other descendants of their last common ancestor). [7]
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-- Philcha ( talk) 12:10, 7 August 2008 (UTC)
Couldn't find a cladogram in recent NJB work; suspect the one drawn will have to be based on what he writes less explicitly about the relationships he is prepared to accept, and that he proposes for Wiwaxia etc. Martin ( Smith609 – Talk) 21:11, 15 August 2008 (UTC)
Please amend if you think there are significant errors or omissions, as this is a complex package of articles and the analysis of options needs to start off on the correct basis:
-- Philcha ( talk) 21:18, 28 August 2008 (UTC)
At present the debate is presented chronologically in all the articles. This is good in terms of completeness, but increases duplication - especially in the case of Butterfield, whose views appear to have changed the least.
Alternatives:
One episode on the career of the chess player Howard Staunton is very controversial (commentators occasionally use unparliamentary language). I created The Staunton-Morphy controversy to house a blow-by-blow account to which Howard Staunton can refer. Then the chess gang (including Philcha) can figure out how to produce a neutral summary in Howard Staunton.
Advantages of adopting this approach for Halwaxiid and related articles:
Disadvantages:
-- Philcha ( talk) 21:54, 28 August 2008 (UTC)
Now that I've saved the saga at Debate about Cambrian Lophotrochozoans, I feel more comfortable about attempting a thematic approach. The biggest single problem is the 2 cladograms in Conway Morris & Caron (2007), but I wouldn't mind describing them separately. OTOH I like the advantages:
So the groupings would be:
What do you think? -- Philcha ( talk) 11:09, 29 August 2008 (UTC)
I now think a thematic presentation is not a great idea, as it would stretch even my liberal interpretation of WP:OR and WP:SYNTH too far - the point that Caron, Scheltema, et al (2006)'s position is "stem molluscs, but not monophyletic" illustrates this.
I'll now try a table to summarise what goes where. Note that the possible Halkieriid- Chancelloriidae link gets in as a possible spoiler. -- Philcha ( talk)
Halkieriid | Wiwaxia | Odontogriphus | Orthrozanclus | Chancelloriidae | Halwaxiid | |
---|---|---|---|---|---|---|
The great debate | brief | brief | brief | brief | no | full |
Halkieriid: description | full | minimal | no | minimal | minimal | brief |
Halkieriid: phylo - molluscs, etc. | brief | minimal | no | minimal | no | full |
Halkieriid: phylo - Chancelloriidae | full | no | no | no | no | brief |
Wiwaxia: description | minimal | full | minimal | no | no | brief |
Wiwaxia: phylogeny | minimal | brief | brief | no | no | full |
Odontogriphus : description | no | minimal | full | no | no | brief |
Odontogriphus : phylogeny | no | minimal | brief | no | no | full |
Orthrozanclus: description | minimal | minimal | no | full | no | brief |
Orthrozanclus: phylogeny | minimal | minimal | no | no | no | full |
Chancelloriidae: description | brief | no | no | no | full | brief |
Checklist:
Halkieriid | Wiwaxia | Odontogriphus | Orthrozanclus | Chancelloriidae | Halwaxiid | |
---|---|---|---|---|---|---|
The great debate | brief Done | brief | brief | brief Done | no Done | full Done |
Halkieriid: description | full Done | minimal | no Done | minimal | minimal | brief Done |
Halkieriid: phylo - molluscs, etc. | brief | minimal | no Done | minimal | no Done | full Done |
Halkieriid: phylo - Chancelloriidae | full Done | no Done | no Done | no Done | no Done | brief Done |
Wiwaxia: description | minimal | full Done | minimal | no Done | no Done | brief Done |
Wiwaxia: phylogeny | minimal | brief | brief | no Done | no Done | full Done |
Odontogriphus : description | no Done | minimal Done | full Done | no Done | no Done | brief Done |
Odontogriphus : phylogeny | no Done | minimal | brief | no Done | no Done | full Done |
Orthrozanclus: description | minimal | minimal | no Done | full Done | no Done | brief Done |
Orthrozanclus: phylogeny | minimal | minimal | no Done | no Done | no Done | full Done |
Chancelloriidae: description | brief | no Done | no Done | no Done | full Done | brief Done |
Since I've been pre-occupied with useful WP activities, I didn't notice that in Sept 2008 some (anon) put a banner "This article contains weasel words, vague phrasing that often accompanies biased or unverifiable information" at the top of the article. There's nothing unverifiable here. To support a claim that some of the info is biased, the perp would have to read and understand about a dozen scientfic papers. It would also have been helpful rather than annoying if the perp had provided some examples. So guess what I'm going to do now. -- Philcha ( talk) 19:50, 28 April 2009 (UTC)
A reference was recently added to this article using the Cite DOI template. The citation bot tried to expand the citation, but could not access the specified DOI. Please check that the DOI doi:10.1111/j.1502-3931.1984.tb02022.x has been correctly entered. If the DOI is correct, it is possible that it has not yet been entered into the CrossRef database. Please complete the reference by hand here. The script that left this message was unable to track down the user who added the citation; it may be prudent to alert them to this message. Thanks, Citation bot 2 ( talk) 19:52, 26 July 2010 (UTC)
This article is rated Start-class on Wikipedia's
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The dorsal sclierete spikes look a little like 'morphed' versions, of the lateral 'side plates', on Anomalocaris & Opabinia. —Preceding unsigned comment added by 66.235.26.150 ( talk) 18:40, 1 March 2011 (UTC)
Wiwaxia, found so far only in the Burgess Shale, had chitinous armor consisting of long vertical spines and short overlapping horizontal spines. It also had what looked like a radula (chitinous toothed “tongue”), a feature which is otherwise only known in molluscs. Some researchers think the pattern of its scales links its closely to the annelids (worms) or more specifically to the polychaetes (“many bristles”; marine annelids with leg-like appendages); but others disagree. [1] [2]
Orthrozanclus, also discovered in the Burgess Shale, had long spines like those of the wiwaxiids, and small armor plates plus a cap of shell at the front end like those of the halkieriids. The scientists who described it say it may have been closely related to the halkieriids and the wiwaxiids. [3]
Halkieria resembled a rather long slug, but had a small cap of shell at each end and overlapping armor plates covering the rest of its upper surface – the shell caps and armor plates were made of calcium carbonate. Its fossils are found on almost every continent in early to mid Cambrian deposits, and the “small shelly fauna” deposits contain many fragments which are now recognized as parts of Halkieria’s armor. Some researchers have suggested that halkieriids were closely related to the ancestors of brachiopods (the structure of halkieriids' front and rear shell caps resembles that of brachiopod shells) and to the wiwaxiids (the pattern of the scale armor over most of their bodies is very similar). [4] Others think the halkieriids are closely related to molluscs and have a particularly strong resemblance to chitons. [5]
Odontogriphus is known from almost 200 specimens in the Burgess Shale. It was a flattened bilaterian up to 12 cm (5 in) long, oval in shape, with a ventral U-shaped mouth surrounded by small protrusions. The most recently found specimens are very well preserved and show what may be a radula, which led those who described these specimens to propose that it was a mollusc. [6] But others disputed the finding of a radula and suggested Odontogriphus was a jawed segmented worm belonging to the Lophotrochozoa (a “super-phylum” which contains the annelids, brachiopods, molluscs and all other descendants of their last common ancestor). [7]
References
{{
cite journal}}
: CS1 maint: date and year (
link)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
{{
cite journal}}
: Check date values in: |date=
(
help); Unknown parameter |coauthors=
ignored (|author=
suggested) (
help)CS1 maint: date and year (
link)
-- Philcha ( talk) 12:10, 7 August 2008 (UTC)
Couldn't find a cladogram in recent NJB work; suspect the one drawn will have to be based on what he writes less explicitly about the relationships he is prepared to accept, and that he proposes for Wiwaxia etc. Martin ( Smith609 – Talk) 21:11, 15 August 2008 (UTC)
Please amend if you think there are significant errors or omissions, as this is a complex package of articles and the analysis of options needs to start off on the correct basis:
-- Philcha ( talk) 21:18, 28 August 2008 (UTC)
At present the debate is presented chronologically in all the articles. This is good in terms of completeness, but increases duplication - especially in the case of Butterfield, whose views appear to have changed the least.
Alternatives:
One episode on the career of the chess player Howard Staunton is very controversial (commentators occasionally use unparliamentary language). I created The Staunton-Morphy controversy to house a blow-by-blow account to which Howard Staunton can refer. Then the chess gang (including Philcha) can figure out how to produce a neutral summary in Howard Staunton.
Advantages of adopting this approach for Halwaxiid and related articles:
Disadvantages:
-- Philcha ( talk) 21:54, 28 August 2008 (UTC)
Now that I've saved the saga at Debate about Cambrian Lophotrochozoans, I feel more comfortable about attempting a thematic approach. The biggest single problem is the 2 cladograms in Conway Morris & Caron (2007), but I wouldn't mind describing them separately. OTOH I like the advantages:
So the groupings would be:
What do you think? -- Philcha ( talk) 11:09, 29 August 2008 (UTC)
I now think a thematic presentation is not a great idea, as it would stretch even my liberal interpretation of WP:OR and WP:SYNTH too far - the point that Caron, Scheltema, et al (2006)'s position is "stem molluscs, but not monophyletic" illustrates this.
I'll now try a table to summarise what goes where. Note that the possible Halkieriid- Chancelloriidae link gets in as a possible spoiler. -- Philcha ( talk)
Halkieriid | Wiwaxia | Odontogriphus | Orthrozanclus | Chancelloriidae | Halwaxiid | |
---|---|---|---|---|---|---|
The great debate | brief | brief | brief | brief | no | full |
Halkieriid: description | full | minimal | no | minimal | minimal | brief |
Halkieriid: phylo - molluscs, etc. | brief | minimal | no | minimal | no | full |
Halkieriid: phylo - Chancelloriidae | full | no | no | no | no | brief |
Wiwaxia: description | minimal | full | minimal | no | no | brief |
Wiwaxia: phylogeny | minimal | brief | brief | no | no | full |
Odontogriphus : description | no | minimal | full | no | no | brief |
Odontogriphus : phylogeny | no | minimal | brief | no | no | full |
Orthrozanclus: description | minimal | minimal | no | full | no | brief |
Orthrozanclus: phylogeny | minimal | minimal | no | no | no | full |
Chancelloriidae: description | brief | no | no | no | full | brief |
Checklist:
Halkieriid | Wiwaxia | Odontogriphus | Orthrozanclus | Chancelloriidae | Halwaxiid | |
---|---|---|---|---|---|---|
The great debate | brief Done | brief | brief | brief Done | no Done | full Done |
Halkieriid: description | full Done | minimal | no Done | minimal | minimal | brief Done |
Halkieriid: phylo - molluscs, etc. | brief | minimal | no Done | minimal | no Done | full Done |
Halkieriid: phylo - Chancelloriidae | full Done | no Done | no Done | no Done | no Done | brief Done |
Wiwaxia: description | minimal | full Done | minimal | no Done | no Done | brief Done |
Wiwaxia: phylogeny | minimal | brief | brief | no Done | no Done | full Done |
Odontogriphus : description | no Done | minimal Done | full Done | no Done | no Done | brief Done |
Odontogriphus : phylogeny | no Done | minimal | brief | no Done | no Done | full Done |
Orthrozanclus: description | minimal | minimal | no Done | full Done | no Done | brief Done |
Orthrozanclus: phylogeny | minimal | minimal | no Done | no Done | no Done | full Done |
Chancelloriidae: description | brief | no Done | no Done | no Done | full Done | brief Done |
Since I've been pre-occupied with useful WP activities, I didn't notice that in Sept 2008 some (anon) put a banner "This article contains weasel words, vague phrasing that often accompanies biased or unverifiable information" at the top of the article. There's nothing unverifiable here. To support a claim that some of the info is biased, the perp would have to read and understand about a dozen scientfic papers. It would also have been helpful rather than annoying if the perp had provided some examples. So guess what I'm going to do now. -- Philcha ( talk) 19:50, 28 April 2009 (UTC)
A reference was recently added to this article using the Cite DOI template. The citation bot tried to expand the citation, but could not access the specified DOI. Please check that the DOI doi:10.1111/j.1502-3931.1984.tb02022.x has been correctly entered. If the DOI is correct, it is possible that it has not yet been entered into the CrossRef database. Please complete the reference by hand here. The script that left this message was unable to track down the user who added the citation; it may be prudent to alert them to this message. Thanks, Citation bot 2 ( talk) 19:52, 26 July 2010 (UTC)