Talk:Reptile

Shouldn't it say in the opening that birds are reptiles?

Seems like it's important to mention. ScienceApe (talk) 12:50, 2 November 2011 (UTC)

It is a question of definition. Under the traditional definition (the definition used in the article), birds are not reptiles, rather they (and mammals) have evolved from reptiles. There's no shortage of newer propositions of definitions of "Reptilia", with or without birds. This is abundantly covered in the classification section. Having said that, a sentence about in in the lede would do. perhaps:

The class Reptilia, covering the basal amniote stock have given rise to both the classes of birds and mammals. Thus under phylogenetic nomenclature, both are reptiles.

Would that do? Petter Bøckman (talk) 19:32, 2 November 2011 (UTC)

Do a majority of researchers still consider Synapsids to be reptiles? I'd leave mammals out of it, except in sections dealing with the history. Mammals are certainly not reptiles under phylogenetic nomenclature. MMartyniuk (talk) 12:42, 3 November 2011 (UTC)

Depends on how you apply the names. "Traditional" phylogenetic nomenclature did not used the name Reptilia (they have worked actively to get rid of it), so it's not surprising that you won't find any phylogenetic references for mammals being reptiles in disguise. The logic behind phylogenetic nomenclature is however forward enough: If reptiles are amniotes sans birds and mammals (the "common" interpretation), then obviously mammals are reptiles phylogenetically. The "mammals are not reptiles" (or "did not evolve from reptiles) stance is only viable under a crown group or node based definition anchored in living groups. Now, there are certainly no shortage of such definitions, though they usually use the name Sauropsida rather than Reptilia. I do agree that there's no explicit sources for mammals "being" reptiles though. What about:

The class Reptilia, covering the basal amniote stock have given rise to both the classes of birds and mammals. Birds are included in Reptilia under some phylogenetic definitions, see Sauropsida.

Better? Petter Bøckman (talk) 21:00, 3 November 2011 (UTC)

It may be best to split "Reptilia" from "Reptile." The Reptile article could then cover the classic reptiles, with appropriate mentions of taxonomic relationships to birds and dinosaurs. The Reptilia article could then cover explicitly the scientific/classification issues, and include birds and dinosaurs integrated within the article along with the classic reptiles. Rlendog (talk) 02:54, 20 December 2011 (UTC)

The article you propose for "Reptilia" is already covered under Sauropsida. The demarcation of the term Reptilia is very well covered in this article. Splitting "reptile" and "Reptilia" won't ad anything, particularly as we already have a Sauropsida article. I have edited the lede slightly to mention the other use of the term Reptilia. Petter Bøckman (talk) 08:20, 20 December 2011 (UTC)

You added "birds are included in Reptilia under some phylogenetic definitions." Are there any phylogenetic definitions of Reptilia that do not include birds? MMartyniuk (talk) 13:11, 20 December 2011 (UTC)

Your latest edit looks good to me, I like the rearrangement of the text too. Petter Bøckman (talk) 13:19, 20 December 2011 (UTC)

Non-synapsid synapsids?

I'm a bit curious about a recent edit. It says: While both branches began with the original anapsid-type skulls, they both independently evolved various configurations of multiple additional skull openings. If I remember correctly, there are anapsid Eureptiles, but do we have any synapsid critters (really, undoubtly synapsid) with no temporal opening? While it stands to reason that it well could have been such beasts, do we have the critter? If not, I strongly suggest we retain the original wording. It was less specific, but had the advantage of catering both ways of classifying. Petter Bøckman (talk) 20:49, 20 December 2011 (UTC)

I could have sworn I recalled some basal synapsids with anapsid skulls but I could be mistaken. Best revise it until I can dig something up. The most derived non-amniote reptiliomorphs were anapsid, right? Or is the anapsid skull a derived trait re-evolved in true reptiles?MMartyniuk (talk) 14:00, 21 December 2011 (UTC)

I'll look into the synapsid thing too, and see if I can come up with something. If I remember correctly, there's some very badly crushed skull about somewhere, with questionable reconstruction.

You are right about the early reptiles, critters like Hylonomus had inherited a skull that would look equally much at home in any of the small, advanced reptilimoprphans. The only trait to disappear in the transition was the pronounced otic notch found in labyrinthodnonts, but non in reptiles. Some of the critters suggested as ancestors of amniotes or early amniotes like Casineria, Westlothiana and Solenodonsaurus have them greatly reduced or lacking all together. Petter Bøckman (talk) 19:14, 21 December 2011 (UTC)

Edit: I have made a provisionary version of the first section (Anapsid, Diapsid etc), please improve it! As for the use of "Anapsida" as a name for a coherent, though paraphyletic, group, it is what everyone from Romer to Modesto and Anderson (the latter are hard core PhyloCode fans) call them, so I suppose it is OK to use like I have. The term "true reptiles" is a bit unfortunate, as it could be taken to mean Eureptilia, we might want to find a better term. Then again, when we come down to details like the composition of Eureptilia, the tree isn't really all that stable, I think we are better served by sticking to the larger picture. Petter Bøckman (talk) 19:53, 21 December 2011 (UTC)

Isn't Synapsida defined by the synapsid skull? The oldest synapsids like Archaeothyris have these skull openings. That means anything without a synapsid skull isn't a synapsid. Either the ancestor of synapsids and sauropsids had an anapsid skull, or it had a synapsid skull and sauropsids became secondarily anapsid. I've never heard anything about this second possibility. Maybe its best to say: While both branches descended from a common ancestor with the original anapsid-type skulls, they both independently evolved various configurations of multiple additional skull openings. Smokeybjb (talk) 17:09, 25 December 2011 (UTC)

This is the old classification debate again, though with a twist. If you define synapsids as you have done (and it certainly is the original and a well used definition), then all synapsids have the synapsid fenestra. This is however a Linnaean (or traditional) definition. If you on the other hand prefer phylogenetic nomenclature and use a stem-based definition (I believe this is the most common phylogenetic definition for synapsids, going back to Goodrich), then MMartyniuks edit may be quite accurate. However, there's a twist here: We do not know exactly how the split happened, who the last common ancestor was, but it is not a far fetched assumption that the last common ancestor was an anapsid. Thus, the evolution of the synapsid fenestra would have happened in the stem. It is on the other hand also possible that the last common ancestor had evolved a thinning of the skull roof to give room for the chewing muscles, and that the fenestra run all the way to the bottom of the stem. There's simply not (presently) any fossils to allow us to tell for sure. This is why I suggest sticking to the bigger picture and not get our nose bogged down details just here. The synapsid article is possibly a better place for such an argument. Petter Bøckman (talk) 21:53, 25 December 2011 (UTC)

I hadn't thought about it being a stem-based taxon, but I agree, this is something for the synapsid or possibly amniote article (since Amniota is synapsids + reptiles in phylogenetic terms). Smokeybjb (talk) 03:47, 26 December 2011 (UTC)

bahavioural topics

I notice that after extensive and interesting treatments of classification, history, and anatomy, there follows one section about repltile behaviours, i.e. "Defense mechanisms". I think this seems odd: why select out defensive behaviours as the ones which need to be described rather than e.g. courting/ mating/ pair-bonding, or hunting and eating, etc.? Maybe a broader view of behaviour might be a good plan? Best wishes, Richard 82.19.24.148 (talk) 23:34, 9 January 2012 (UTC)

This is a good idea, the question is only what we should put in there. I suppose a bit about hunting (most reptiles are carnivores) and perhaps mating games? Petter Bøckman (talk) 12:17, 10 January 2012 (UTC)