Talk:Placoderm

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In the "See Also" section, do people think it's best to leave Dunkleosteus terrelli as it is, pointing at a redirect, or change it to Dunkleosteus terrelli, which doesn't redirect but doesn't look as nice. 193.63.43.10 13:32, 26 March 2007 (UTC)[reply]

Article doesn't exist

I'll have to delete this link, the article doesn't work http://www.amonline.net.au/archive.cfm?id=1137

--HoopoeBaijiKite 20:50, 18 June 2007 (UTC)[reply]

Taxobox Picture Question

Why is it so horrible to use this picture [1] in the taxobox?--Mr Fink (talk) 05:18, 21 April 2008 (UTC)[reply]

Nothing wrong in terms of accuracy as fas as I can tell, so why not using it either in the taxobox or in the text? ArthurWeasley (talk) 20:15, 21 April 2008 (UTC)[reply]

Seems like Nicolás10 has an aversion towards strong contours and bright colours, which is a rather silly rationale for removing images. There is room for both. Funkynusayri (talk) 01:54, 29 April 2008 (UTC)[reply]

Placoderms and sharks are not sister-groups

" ...when more fossil specimens were found, especially the exceptionally well-preserved fossils from the Gogo Reef formation in Australia, Stensiö's theory of sharks and placoderms as sister groups became accepted as fact."

This statement is misleading. While Stensiö's work remains highly respected, the idea of a sister-relationship between chondrichthyians and placoderms has been almost universally rejected by vertebrate palaeontologists since the mid-1990s. The current consensus is that placoderms are stem-gnathostomes and are thus no more closely related to sharks than bony fish are. The Gogo fossils provided strong evidence *against* a placoderm-shark relationship (Gogo placoderms show separate bone for the nasal capsules which are incorporated into the braincase of sharks and bony fish). If no one objects, I will rewrite this section ASAP.

REFS = Goujet, Daniel & Young, Gavin (2004). Placoderm anatomy and phylogeny: new insights. (in) Arratia, Wilson and Cloutier (eds) Recent Advances in the Origin and Early Radiation of Vertebrates. Verlag Dr. Friedrich Pfeil, Munchen, Germany.

Young, G.C. & Goujet, D. & Lelievre, H. (2001) Extraocular muscles and cranial segmentation in primitive gnathostomes - fossil evidence. J. Morphology. 248:304.

Phillipe Janvier's page at the tree of life = http://www.tolweb.org/Gnathostomata/14843

John Long - personal communication.

Ozraptor4 (talk) 01:46, 13 June 2008 (UTC)[reply]

We should elaborate more on why Stensiö's theory has been rejected in favor of placoderms being stem-gnathostomes, like, listing some more traits that the Gogo reef placoderms have demonstrated to have in common with all/most other gnathostomes.--Mr Fink (talk) 03:30, 13 June 2008 (UTC)[reply]

Absolutely - the process which settled the relationships of placoderms to other fish was as intense and complex as the bird-dinosaur ancestry debate. I have most of the key papers on the subject but will take a little while to condense the main points into a succinct and readable account. Note that the Gogo placoderms were probably eclipsed in importance by Taemas-Wee Jasper material in settling the debate. All the Gogo placoderms are highly derived while the older NSW material represents fine preservation of much older/primitive forms. Ozraptor4 (talk) 11:47, 14 June 2008 (UTC)[reply]

Like, concerning how Brindabellaspis' braincase anatomy has more in common with various agnathans?--Mr Fink (talk) 18:06, 14 June 2008 (UTC).[reply]

I think the article should be expanded