Duck Billed Platypus

And if you remembered your reading a little better, you would know that this was in the late eighteenth century. How many Darwinists do you think there were in England in the late eighteenth century?

Yeah, and I recall you being spanked during that one, too.

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Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine

The first specimen of the platypus was brought back to England in 1799, and it was considered as a fake. The Origin of Species by Charles Darwin was published in 1859.So MartinV, with your cosmic wisdom, how many Darwinists do you think there were in 1799?

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Disclaimer:

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Occasionally, owing to the deficiency of the English language, I have used he/him/his meaning he or she/him or her/his or her in order to avoid awkwardness of style.

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He, him, and his are not intended as exclusively masculine pronouns. They may refer to either sex or to both sexes!

Of course. It's easy once you've learn the marsupial synapomorphies. What are you talking about? Yeah, Creationists are so dumb, aren't they?If only they'd known about evolution, they could have diagnosed it as a specialised monotreme.Edited by Dr Adequate, : No reason given.

Not at all. I seems to me that weird creatures represent a much larger problem for an involved infinitely intelligent designer. Was Platypus made from left over parts or what? I am somewhat surprised you bring this up, as this point was overwhelming well defended - and not in your favor!When Platypus specimens arrived in England (prior to Darwin) they were greeted with suspicion. One of the first to examine the Platypus, Robert Knox explained the source of the suspicion... This suspicion was not based on some conflict with natural selection or evolutionary theory like I think you are attempting to allude.

I thk that ti is very telling that Martin should continue going on about this point.What occurred is that the posters on the evolution side looked at the pictures provided and noted the differences. Martin on the other hand would rather believe that the differences could not be there based on his personal interpretation of an anecdote.The simple fact is that if you have a wolf skull and a thylacine skull side-by-side it is easy to tell that the teeth are different. All it requires is a willingness to look. Martin not only lacks that willingness - he believes that nobody else should look, either.

Sounds more like a failure of design inference to me.TTFN,WK

Exactly.The strange thing about Dragoness's husband (a Dragon?) and other creationists using the platypus is that the animal can be used as a very good illustration of evolution. Aren't monotremes the closest living things to the mammal-like reptiles that evolutionary theory predicts as our ancestors?What's interesting about them is that they show clearly that breast feeding comes before live birth in our lineage, which seems to me to make sense, as the former would facilitate the latter.It's fun playing at speculative evolution, and my guess is that our branch of the common ancestor with the modern monotremes was in an environment in which its eggs were vulnerable to a predator or predators, so that any shortening of the period between laying and hatching would be an advantage, leading eventually to instant hatching, then live birth. (That's probably either so obvious that it's standard theory, or completely wrong for some reason I haven't thought of!).

No closer than modern placentals and marsupials -- we're all about 200 million years from the common ancestor. It's true that monotremes retain various primitive characteristics that were more heavily modified in our branch. But I wonder if there are some collection of primitive therapsid characteristics that placentals retain that were lost or modified in monotremes?I also do not like the phrase "mammal-like reptiles", but that phrase seems to be so ingrained that there is probably very little anyone can do about it.

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Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine

Not exactly. Remember that the monotreme of today is as distant from those early ancestors as we are.But they can still teach us much. A few years back some researchers at Duke were looking at "genomic imprinting". In their study they were looking at platypus and opossum and they expected that "genomic imprinting" would not be found in either the monotremes or the marsupials, but at least in the case of one gene, they found imprinting in the opossum.This tells us that the mechanism of "genomic imprinting" goes back even further than thought.You can read more on the study here.

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Aslan is not a Tame Lion

I've done a bit of googling, and I see what you mean about the 200 million years. I think that I'd (wrongly) assumed that our line must've diverged from that of the platypus about 150 million years ago, because that's about when the first placentals appear.I suppose that the "living fossil" view of the platypus comes mainly from the fact that they're amniotes. But what I found interesting in your post was the idea that placentals might retain therapsid characteristics that were lost or modified in monotremes, and indeed, why not? So I was wondering if you had anything particular in mind, even if just speculative ideas.

Interesting link, jar.It also seems to confirm that the monotremes split off our branch earlier than marsupials, rather than a split involving a common ancestor of monotremes and marsupials, then the two as "twigs" of that branch (if I understood rightly). Also, that imprinted genes could be vestigial in higher mammals, although they don't know yet.

This might be closer than my figure. I just quickly looked up and found that the first mammals appeared in the early Jurassic, and the Jurassic began about 200 million years ago. I was just looking for a ball park figure.Now, if one defines mammals as the crown group containing platypusses (platypi?) and humans, then you figure might be more correct. However, if mammals are defined to be some stem group compared to some now extinct outgroup, then the date might be closer to my figure.- Not that I know of -- I would be interesting to find out myself. But it makes sense that there might be. It is unlikely that monotremes have remained completely static over the last 150-200 million years. But who knows? Maybe they really are "living fossils", that is, a taxon that has undergone a minimal amount of morphological change. I doubt it, simply because I haven't heard them called "living fossils", but maybe they are. (Or maybe I have heard them called that, but I don't recall if it was a term that was correctly used.)And, of course, placentals didn't lose all of our primitive therapsid traits -- we generally have four limbs, for example. (We also generally have fur and our females nurse our young as a couple more examples.) So it stands to reason that there should be some primitive therapsid traits that we retain but that the monotremes have significantly modified.I don't know what they are, and maybe there aren't any -- maybe every single trait that we placentals share with our therapsid ancestors are also shared with monotremes. It is possible that we placentals are the product of some pretty extensive evolution that left very little of our therapsid heritage, except for those traits that happen to be shared by the monotremes as well.I have ordered McKenna and Bell's classification of mammals -- it hasn't arrived yet, but maybe it might shed some light on this question. Or maybe someone who already is an expert on this (or is better at using Google than I am) will chime in with the answer.

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Actually, if their god makes better pancakes, I'm totally switching sides. -- Charley the Australopithecine

Actually, I might have a quick one without googling. Teeth. Platypus babies still have them, but not adults. Would that fit the bill?

I only quoted Dawkins observation about Oxford students of zoology having problem to tell apart skuls of marsupial and placental wolfs. If people here know dental formulas of both species by heart (I am not sure students at Oxford are allowed to have written dental formulas on cheat sheet during "telling apart" exam) I agree you are experts who are able to distinguish between them.
Btw. do people here know by heart also dental formulas of all extant mammalian and marsupalian orders, or focused only to mentioned ones?