Talk:Orthrozanclus

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Sources[edit]

SCM & J-B Caron, Halwaxiids and the Early Evolution of the Lophotrochozoans; Science 2 March 2007:

Vol. 315. no. 5816, pp. 1255 - 1258, DOI: 10.1126/science.1137187 (already ref'd) - 1st full description.

Caron, J.-B., and Jackson, D.A. (2006). "Taphonomy of the Greater Phyllopod Bed Community, Burgess Shale". Palaios. 21: 451–465. doi:10.2110/palo.2003.P05-070R. Retrieved 2008-08-04.{{cite journal}}: CS1 maint: multiple names: authors list (link) - "scleritomorph C"
"Science Magazine Publishes Article Co-authored by ROM Palaeontologist Jean-Bernard Caron describes a new body-armoured species from the Middle Cambrian Burgess Shale". Royal Ontario Museum. Retrieved 2008-08-04. - history of discovery

-- Philcha (talk) 14:01, 4 August 2008 (UTC)[reply]

There's a copy of the pic at Newly Identified Species Of Spiny Snail-like Creature, 505 Million Year Old, Described -- Philcha (talk) 16:10, 7 August 2008 (UTC)[reply]

clades and Orthozanclus[edit]

This sentence has changed back and forth a couple of times:

"These similarities suggest that Orthrozanclus was an intermediate form between Wiwaxia and the Halkieriids and that all three of these taxa formed a clade, in other words a group that consists of a common ancestor and all of its descendants."

The current version has "monophyletic" before the word "clade".

It wasn't my intention to start an edit war; I didn't notice I previously edited this article and it was reverted.

The comment associated with the reversion suggests we read the main source, but I'm unsure which source that refers to. Neither the Butterfield 2007 nor Conway Morris & Caron seem to weigh in on the specific question of which wording is appropriate. It still seems to me that the word "monophyletic" adds nothing to the clarity of the sentence, and I suggest removing it. Please elaborate if you think differently (or similarly, for that matter).

Cheers, Cephal-odd (talk) 18:19, 19 May 2009 (UTC)[reply]

The real problem IIRC is that Conway Morris & Caron (2007) is rather odd, altough I haven't read it closely since Aug 2008. IIRC they talk of the Halwaxiids as a "clade" and / or "monophyletic" early in the paper, but look at the cladograms - the Siphogonotuchida spoil the party in "Hypothesis 1", which they say is "better" but "not robust" - without much explanation of either description. I got the feeling while reading the paper that there was some sort of difference between the authors - if you look at their other papers (see Halwaxiid for the whole messy story), Caron is all for calling Wiwaxia and apparently the other Halwaxiids stem-group molluscs, while Conway Morris started that way (paper on Wiwaxia, 1985) but has been a lot more cautious since Conway Morris & Peel (1995).

In late summer 2008 I thought that the adherents of the "annelid" and "mollusc" hypotheses (Butterfield vs most others, respectively ; Conway Morris sitting on the fence; Eibye-Jacobsen saying neother is convicing) were better at undermining the opposing hypothesis than at supporting their own. A budy of mine who's a paleo post-grad specialising in the early Cambrian agrees with the "neither convincing" view and suggested that Butterfield is mainly concerned to prevent a premature jump to the "mollusc" conclusion. I a started working on invertebrate zoology articles to see if that would improve my understanding - so far it has not made the Halwaxiid debate any clearer to me, and I notice most Cambrian paleontologists find other things to do.

Bottom line - the situation is so confused that I suspect even trying to be rigorous about terms is not going to clarify it at all. --Philcha (talk) 06:23, 22 May 2009 (UTC)[reply]