Talk:Sphenacodontia

definition unclear

The article defines this clade thus:

"Sphenacodontia is the name given to the clade that includes the Sphenacodontidae and all their descendants (including mammals)"

but it's ambiguous how that differs from the definition given for Sphenacodontoidea:

"Sphenacodontoidea is the name given to the clade that includes the most recent common ancestor of the Sphenacodontidae and the Therapsida and their descendants (including mammals)."

The Sphenacodontia definition implies that Sphenacodontidae is paraphyletic with respect to therapsids and mammals, while the Sphenacodontoidea definition implies that Sphenacodontidae is more a sister group. Given the word "includes", the definition of Sphenacodontia allows it to be a broader clade than Sphenacodontoidea, but it's vague about how broad it is. Perhaps someone familiar with Synapsids can sharpen the wording?

Cheers, Cephal-odd (talk) 04:09, 16 March 2009 (UTC)

The difference between the Sphenacodontia and the Sphenacodontoidea, as defined, is their point of origin. The Sphenacodontoidea begin at the root (most recent common ancestor) of the Sphenacodontidae. The root of the Sphenacodontia is apparently left unspecified However in the Sphenacodontoidea page it states "The Sphenacodontoidea evolved from earlier Sphenacodontia such as Haptodus..." making the Sphenacodontia a larger group in which the Sphenacodontoidia is included.

As for the Sphenacodontidae being paraphyletic, so what. Perfectly sensible. Keeps the taxon (family) orderly.

Regards J.H.McDonnell (talk) 14:18, 16 September 2010 (UTC)

Wikipedia's Pelycosaur page

Wikipedia's "Pelycosaur" page says "Because more advanced groups of synapsids evolved directly from 'pelycosaurs', the term had fallen out of favor among scientists by the 21st century, and is only used informally, if at all, in the modern scientific literature." This seems to contradict the "Sphenacodontia" page's use of "Order Pelycosauria". — Preceding unsigned comment added by 50.96.57.13 (talk) 14:41, 15 October 2014 (UTC)

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