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Shouldn't the entry mention that pelycosaurs were mammal like reptiles?
- No, because they weren't what is usually meant by the term. More properly, they were the line that led to the mammal-like reptiles, or Theraspids. CFLeon 07:47, 7 May 2006 (UTC)
A new definition for Pelycosauria is here provided:
Pelycosauria Cope, 1878 New defintion - All synapsids closer to Eupelycosauria and Caseasauria than to basal Synapsida.
- yes but Pelycosaurs are basal Synapsids; it's a paraphyletic group M Alan Kazlev 04:28, 26 August 2006 (UTC)
O.k. they're paraphyletic, No biggie. Keeps the taxon within sensible limits. Also its better to define a taxon (genus, family, order, etc) on observable characters rather than, more closely related to this than to that. J.H.McDonnell (talk) 00:57, 17 September 2010 (UTC)
Text contradicts illustration?
According to the text, the clade Eupelycosauria includes the Theraspids. Acoording to the taxonomy list, they are a sub-order of order Pelycosaur beside order Theraspida.
I get that there are competing systems out there, but someone should clean that up, at least a note or a comment. --Sukkoth 20:55, 27 September 2007 (UTC)
It seems a lot of bother is made over clades which are based on a concept not all that difficult to understand. Clades of best used when evolutionary relationships are the issue, especially those which follow. When the concern is over a particular and well defined group, such as Pelycosaurs, the cladistic approach isn't particularly useful, if at all. In this case its better to think of them in the traditional sense as an ordinary taxon.
When it says "At least two pelycosaur clades independently evolved a tall sail, ..etc" it could have just as well have said: at least two pelycosauran families independently evolved a tall sail. For practical purposed in this case the two terms are interchangeable, except that clade is more ambiguous.
comparison to Late Devonian extinction ??
The late Devonian extinction c.370Ma can be construed, as resulting from the fishes' evolution of jaws, and teeth, c.400Ma; fish then went on a global feeding frenzy, and gradually drove many other species extinct; so explaining the higher background-rate of (marine) extinction after 400Ma. A hundred million years later, the evolution of warm-blood, by basal Therapsids, may have been a similar "quantum leap" in evolution, causing a burst of Therapsid expansion across Pangea, which came at the expense, of more primitive species, who suffered Olson's Extinction c.270Ma. The article's reference to "late surviving forms" of Pelycosaurs, echoes similar statements for (even more primitive) Varanopidae, who also eked out survival, in then-arctic South Africa, until c.260Ma. Plausibly, warm-blooded Therapsids evolved an advanced(-for-earth) feature c.270Ma, which was then a "quantum leap" over contemporary species, even as eons earlier, jawed fish evolved an advanced feature. Perhaps such biogenic mass extinctions become less frequent, over evolutionary time, as more advanced features become more common? If so, then modern anthropogenic extinctions may be part of a persistent pattern, spanning nearly a half billion years, of "quantum advances" bringing about biogenic mass extinctions (not caused by geologic, or cosmologic, pheonomena). Contact with advanced species may have caused the late Devonian, and mid Permian, mass extinctions.184.108.40.206 (talk) 12:26, 22 October 2012 (UTC)