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Post by appybugs on Sept 14, 2011 4:26:17 GMT -8
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Post by Adam Cotton on Sept 14, 2011 8:44:58 GMT -8
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Post by starlightcriminal on Sept 14, 2011 11:26:09 GMT -8
It is interesting, definitely begs further investigation. I am still not convinced (one way or the other I should say, still a "maybe" in my mind) that this qualifies it as a distinct species and not just a well-maintained hybrid, especially because so much of these "intermediate" markers represented in Fig. 3 can easily be problems related to the way we handle molecular data. Just listen to this sentence in the introduction- "Also, there are no examples of hybrid species that maintain their genomic identity while in contact with both parental species, which is important because sympatry may suggest that hybrid species are maintained by natural selection." Unfortunately not much pressure can be demonstrated as all three have intermediate zones where each is found. Why then differentiate if there is not differential pressure?
The molecular clock models, for example, are known to be hugely flawed and vary quite a bit in their accuracy. Just the order of models used can have a profound effect on the purported distinction period for a particular species and for something reported to be as recent as P. appalachiensis this is especially confounding. There is little discussion of historical population size, differences in metabolic rates, efficiency of DNA repair or generation length all of which muddies the ability to declare a hybrid with high rates of natural occurrence a distinct species. In plants this is commonly noted (Cattleya xhardyana is a great example, which under the paradigm we have with appalachiensis would warrant its own species classification, yet this is not even considered a possibility for this long-recognized natural hybrid), I'm not sure why a butterfly would warrant exception other than in this specific case it is far more exciting to describe for a taxonomist.
There is much discussion of introgression and lack of back-crossing but there is no mention whatsoever of substitution rates. It is well known that certain regions of some genes are far more likely to undergo substitution than others so simply stating that no obvious re-infusion of a particular parent species back into the hybrid implies nothing about the distinction of the hybrid as a species. This is simply where certain substitutions from the parent are preferentially integrated while other genes resist crossing consistently. That means that glaucus could have been crossing over and over with this questionable new species and it would not be detected by any of the molecular methods used because repeat, preferential substitution is not accounted for, i.e. a substitution of the same gene over and over from one parent. Also some regions are repaired by telomeres more efficiently than others so maintenance or lack thereof for a particular gene would also muddy the waters if we are to simply use direct comparison of genetic variation and mapping as the key hallmark for distinction. None of this is proof that appalachiensis is in fact being naturally maintained as distinct, just that there is a tendency to have similar results from crossing. It might already be there, it might be completely artificial or it might be that it is well on its way to becoming a species. Not conclusive.
Then there are all of the conceptual problems with using these types of models anyway and ironically they are rarely addressed by people utilizing them (usually it is the creators of the models and statisticians that pick them apart for applicability and flaws), that being that our understanding of what makes something distinct is based on what we currently hold up as "important" in the genome. That of course changes by decade practically, at least over the last 40 years or so. I personally would not make such a declaration in my own professional writing but then I am also not a taxonomist that would have an interest in being able to name and describe a new species. I'm not saying this person is just after notoreity, just that the time line may be different because if you don't move fast in taxonomy someone will intentionally steal your discovery out from under you (Phragmipedium kovachii is an example of this, there are countless others) by publishing in any old hack journal that will take the paper. Once it's published, you can claim the discovery whether you did most of the work or not. So I think maybe these things are hasty to me but maybe not to people in some field of taxonomy, I'm not sure. Good news is that almost all of the molecular data that we have so far confirms almost all the phylogenetic relationships that taxonomists made prior to the advent of genetics, at least to very close relatives. Sometimes species and genera get lumped but it is rare to find anything that was way off base and most of that was done simply with morphology.
I argue the counterpoint and not pro simply because the paper is already arguing for it, not because I entirely disagree with one view or the other. I am merely pointing out why I have reservations and what would be good to investigate further if you really wanted a convincing study- maybe some of you are pros that have time and resources to do this kind of work. Some modeling of what crossing is successively favored. It does seem like it is at least becoming distinct by virtue of the varied voltinism but that can be and effect of innumerable stimuli so even here we really need to know more about what is going on.
So, in conclusion I wouldn't want to spend a bunch of money on a specimen because it is a "new species" all of the sudden but I do want to get my hands on a series now because it is very intriguing indeed. Good thing they are found close by. Thanks for the updates!
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Post by nomihoudai on Sept 14, 2011 12:22:40 GMT -8
Like that one time when
- Nolidae bounced back and forth between Noctuidae?
- We lost half of Rhopalocera families into Nymphalidae (Satyridae, Morphidae, Amathusiidae, Morphidae, Danaidae, Brassolidae, Ithomiidae)
- We lost Riodinidae into Lycaenidae ?
- We lumped Lymantriidae and Arctiidae into Noctuidae ?
- We could rewrite the whole crap again because now Erebidae got errected and Lymantriinae and Arctiinae was a part of it ?
- Eutelia that nobody ever spoke of got a family on it's own,lol ?
- Pyralidae turned 'Macro' ( They are somwhere close to Paplionidae, Pieridae, Lycaenidae, Nymphalidae and Hesperiidae)
- and we don't have a clue what the hell Millieriidae is as it looks this 4 taxon family is polyphyletic ?
Oh thank god we got molecular genetics, it "confirms" everything so well...
p.S. This are jsut things that changed in the last 4 years and only things that come to my mind within 5 minutes that I read your post
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Post by wollastoni on Sept 14, 2011 23:11:53 GMT -8
For my own collection, I keep the old family classification (Satyridae, Danaidae...).
The big lumping into Nymphalidae always appeared "strange" to me. In addition to very different patterns, those butterflies do not share the same behaviour, first stage aspects, foodplant ...
In the "lumpers vs splitters war", I have always been aside lumpers but not in this case...
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Post by beetlehorn on Sept 15, 2011 2:36:05 GMT -8
I agree with you on this matter. I find it somewhat disturbing that taxonomists have lumped all these large families into one. I have to wonder what they'll do next?!? To place such families as Morphidae, Amathusidae, Danaidae, Satyridae, etc. under the same classification and name them Nymphalidae, is in my opinion rather ridiculous. A satyrid the same as a nymphalid????Come on give me a break!! Even as a child when I started collecting the difference between a Pararge aegeria and an Apatura ilia was so obvious I just knew they had to be classified into separate families. Their habitats were within the same area, but everything else was different, behavior, flight pattern, physical appearance, etc. I realize the issue between P. glaucus, and P. appalachiensis is on a species/subspecies level, but it is to me just another example of how diverse life on this planet is. As for my personal collection I too keep not only the families of Nymphalidae, Satyridae, Morphidae, and others separate, but I also regard the few P. appalachiensis I have and P. glaucus specimens as distinct. Lets not forget, these swallowtails were or possibly still are listed under the genus "Heraclides", as for my collection I have them all listed as "Papilio". I guess what I am trying to say is that we all know them as what they are traditionally classified, why try to confuse things by constantly changing the taxonomy. Perhaps the war between the "lumpers" and "splitters" is on-going because they know that if they keep things stirred up they will continue recieving a paycheck. Tom
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Post by starlightcriminal on Sept 15, 2011 5:18:22 GMT -8
The tiny list of what appear to be strange "lumpings" that is provided is quickly dwarfed by every other thing that is till the same- start listing things are confirmed, there isn't space here to even start. We don't even talk about the multitudes of confirmations generally because it's not very interesting to hear that we can prove the sky is blue, right?
Plus you missed the part where I mentioned that the relationships are what is correct- nothing you mention is "way off base" to quote myself, we still think all those butterflies are closely related, we are simply saying they are more closely related than we originally thought. So where is the "way off base" I described that you quoted? And still that is just a handful of species. It would take forever to list everything that didn't change. Sometimes nomenclature has to change because there were some funny subdivisions made based on characters that seemed important phenotypically but ultimately are not unique. That isn't to say there aren't some kinks, that's my point about appalchiensis- there are a number of "lumps" and "splits" that seem odd to me too and may be based on an overemphasized genomic difference that ultimately may prove to be less significant that initially thought- this is a case by case thing which is why it is scarce to happen. But are we lumping all over the place and changing most things names around? Not even close, not when looking at the overall number of species. Considering the overwhelming number of species on the earth, and with much of the Tree of Life project available for browsing if you feel like checking this for yourself because it is a waste of time to list 99 good species for every one you mention above (though very easy, mind you), you will be shocked at how closely taxonomists and molecular geneticists can confirm each other's assumptions- the rate of accuracy is both staggering and reassuring. We don't like to believe geneticists when we feel that we 'see' something very distinguishing that we are told is not. Somehow we always err on the side of the taxonomist in these scenarios, I am positive it is because it is much easier to think about what you are seeing vs. something you might have to learn a lot about to appreciate because you can't see it and it requires abstract knowledge that isn't easy to relate. The fact remains that there are far more traits on the molecular level than we can ever describe by eye and on the genomic level those things we see by eye are included. It's hard to say whether only five genes control all those things we perceive as different and they are just a reflection of an overwhelming similarity between what appear to be distinct genera or if they are only the tip of an iceberg in a series of genes that are divergent. The problem lays in the human imposition of boundaries of importance, which may or may not be inclusive or exclusive enough to make a proper distinction. But then nomenclature is the same- a human imposed system with parameters that are somewhat arbitrary. By phenotype, what is the tolerance level for "distinct" either? Both fields are by nature a bit fluid because you still have to assign what is different enough to call something separate. However the fact that both fields agree generally means that two independent approaches result in the same findings- well, that is plain old scientific method right there. More than one independent test that still supports the same conclusions almost all of the time. The vast number of butterflies even have not been re-assigned, right?
Lumpers and splitters comes from the advent of molecular genetics is my guess, it was far less likely to happen before we developed sophisticated molecular techniques. Note that we are only lumping together or subdividing within small sets, almost never completely moving something away from its original phyllogenetic position. The tree of life project, which gets paychecks to many scientists in both taxonomy and genetics (or both, as most are anymore) pays you whether you lump or split, the point is for accurate information not for radical restructuring unless it is required. No one is paying for a particular answer, just whatever answer presents itself. There isn't a right or wrong that will qualify you for a paycheck, you are simply reporting your findings whatever they may be. We do this simply because the full scope of the tree of life project is to help further our understanding of how life evolved on this planet. If we don't substantiate our organization of relationships, the taxonomic system of nomenclature becomes no better than using common names because it won't necessarily reflect anything other than a name we arbitrarily assigned. Why have nomenclature at all then?
Beetle, I think keeping old names from original collection is kind of nice too in that it isn't hard for us to find what the new classification is should we absolutely need it for some reason and it reflects the historical understanding of each specimen, so for the provenance I also like to have the original name used at the time of collection. I do make notes of updates when I find them but I keep the old name too. Who knows, some of those may revert.
It is an interesting conceptual dilemma.
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Post by nomihoudai on Sept 15, 2011 9:20:32 GMT -8
You Sir have not the slightest clue what Noctuoidea are.
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Post by nomihoudai on Sept 15, 2011 9:50:34 GMT -8
The groundpattern of Nymphalidae (using modern and old notation) is different lines of eyepatches in the wings, Pieridae do not have them, Lycaenidae do not have them and Papilios don't have them either... on the other hand turn around any Nymphalid and you see the same horizontal lines and a number of eyespots or tiny tiny dots (which may be missing, but the lines are still there) in between them. Ussing the pattern argument it still is more or less consistent ( excluding Danaidae for the moment  ) Nymphalidae are brush foots, the first pair of legs is reduced, this is also found in the other families you stated. The question was now if the reduced leg or if any characteristic of the other subfamilies was basal and which name the clade should get. I learned the new classification immediately 6 months after I started, so the changes where easy and well to understand for me, I am happy to have only 4 families. |
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Post by pennswoods on Sept 15, 2011 16:16:02 GMT -8
Perhaps the war between the "lumpers" and "splitters" is on-going because they know that if they keep things stirred up they will continue recieving a paycheck. Tom You Sir, are correct. |
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Post by Chris Grinter on Sept 15, 2011 20:53:00 GMT -8
Perhaps the war between the "lumpers" and "splitters" is on-going because they know that if they keep things stirred up they will continue recieving a paycheck. Tom I highly doubt the pay has anything to do with the motivation behind controversy. Half the people that keep stirring the pot are either tenured or retired - no matter how they stir they still get the same check! It comes down to a fundamental belief in how you interpret the data. Every year new analytical methods are invented and revisions will always be needed. Heck genitalia was even the "new" craze decades ago, think of how useful it has been in our field! The interpretation of evolutionary patterns is not a precise nor even particularly accurate science, these debates will continue as long as we're around. |
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Post by beetlehorn on Sept 16, 2011 1:39:18 GMT -8
I suppose I went a bit too far in saying that taxonomists are constantly changing scientific nomenclature in order to continue recieving money. I wonder though why do they change it on so many levels (family, genus, species)? Just because they find a bit of genetic "evidence" that seems to point them in another direction, they suddenly change the nomenclature even on the family level? Then a few years later something else comes along, another opinion, someone else's findings, or perhaps something overlooked, and all of a sudden a species or genus is renamed or it is reverted to it's original standing. Why is our scientific community so eager to reclassify something before all the facts about a given family, genus, species..... are in? It just seems to me that this tends to cunfuse things unneccessarily. For example...decades ago it was called Papilio marcellus, then it was called Graphium marcellus, now it is known as Eurytides marcellus, what will it be next,..... Iphiclides marcellus? I understand that scientific research is a process of elimination in order to get at the final result of a collection of findings. I have to wonder then,with all due respect, if it's not about money, then what else could motivate people to be so eager in this regard? Perhaps the recognition of their research will earn them some other reward, which I am sure many of them deserve. Also at times a certain scientist will find something so staggeringly different, that the facts beg us to completely reconsider our previous understanding, even to the point of reclassifying an entire group of organisms. This brings us back to the first discussion. Where do we draw the line in what actually constitutes a separate species? How far do the scales have to tip in order to give something species designation, and how much evidence does it take to change the classification of something? Is Papilio appalachiensis far enough along in the evolutionary process to actually constitute it as a separate species, or is it merely a subspecies of Papilio glaucus, or should I call it Heraclides glaucus? Lets get all the facts in, or at least as many as we can realistically gather before we start to rename it. So far we are down to the mitochondrial level to distinguish it from the parent species. For a collector, or just the casual entomologist I think it will hold up as a separate species. Many of the physical characteristics are so similar that an untrained eye would consider them the same species. But whenever I pull open a drawer with the two side by side the differences are obvious to me. That plus the differences in flight times, elevation preferences, and localization of populations, are more than enough for this collector to consider the Appalachian Tiger Swallowtail a separate species with it's own designation. Tom
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Post by starlightcriminal on Sept 16, 2011 5:26:42 GMT -8
The reason they change it is easy- they are honestly trying to clarify the relationships between living organisms. Reasons it might be changed more than once would be improved technology, new discoveries in the fairly young field of genetics, a new understanding of the importance of specific genes, and so on. The motivation is to understand, that's all. Why does anyone bother to classify at all? It's the same purpose, whether we use genes or morphology or both. Giving more weight to one over the other is not using all the tools available so you can't expect completely correct answers using only one or the other, and for most of our older classifications only one was available. Even those haven't changed much until we start going back centuries. They are simply tightening up what we already know, even if that requires adjusting the cladogram a little.
I think our perception of the number of changes and the rate at which they are changed is very skewed. Again, we are not talking about all the things that didn't get changed. This isn't some rampant, fun game that taxonomists play- the whole debate reminds me a lot of horticulture vs. botany. Many many horticulturalists hate all the nomenclatural adjustments to their products because it requires keeping constantly on top of the names and changing tags, and so on. However it doesn't make the old name right just because the new name poses some inconveniences. There is the practical application for the general public and then there is a theoretical use reserved mostly for scientists and folks that are so inclined. Mostly, in garden shop you find common names or really old, invalid, or incorrect latin names. Sometimes even invented latin names that are bastardized common names- "alba" is a common one, a form mistaken for a species epithet frequently. But, since we are talking about the scientific application of names, it seems only reasonable for some changes to pop up as prescribed and to try to make as much sense of all of the available information. If we want to use latin nomenclature then it should be used as it is intended, otherwise just stick to common names which are not part of a structure that implies anything about the organism as is the case with the Linnaean system. If we knowingly ignore information because we don't want to change latin names then we are just pretending that the latin name is anything more than a fancy sounding common name because you wouldn't be able to infer anything from it. This binomial system was created for exactly that purpose, any use otherwise is almost a little deceptive (only not intentionally so, of course). Thus it necessarily must change as we improve our understanding of phyllogenetic relationships.
But I also have pointed out the questions you raise, I think it's what started this whole conversation about apalchiensis or subspecies (sorry again!)- because genetics is relatively young and still being parsed through it is a bit arbitrary where we decide to split a species. Not because the people who do it are doing anything different than anyone else in their field, but because we may or may not even be looking at the right genes or have too narrow of a tolerance level before dividing or conversely too broad. That is the conceptual dilemma to which I refer- "where do we draw the line in what actually constitutes a separate species?" We need what you suggest- we need to get all the facts, morphological and genetic with (and this is stressed) consideration given to the potential problems with a new technology and then decide. We've got all kinds of things muddying those waters right now, some of which I mentioned already. Then there are things like epigenetics, mutation as a results of catastrophic change which is not regular and predictable and is looking more and more like the main way in which new species are formed, and so on.
All of that demonstrates quite readily, I think, why names can and should undergo multiple changes if the indications are there. The information we use gets improved and filled out all the time. Sometimes that requires rethinking our classification, even if it means reverting something back to its original name.
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Post by wollastoni on Sept 16, 2011 9:02:29 GMT -8
Papilio genus is already splitted and it looks normal to me IMHO.
Delias genus could also be splitted (if we compare how splitted Western genuses are). About 300 Delias species (maybe 2000 ssp), some very distinct groups.
But it is good thing not to split them : it makes Delias collecting more challenging, and a full Delias collection is an impossible mission (especially because many full species are still to be discovered).
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Post by Adam Cotton on Sept 17, 2011 23:18:05 GMT -8
Lets not forget, these swallowtails were or possibly still are listed under the genus "Heraclides", as for my collection I have them all listed as "Papilio". Tom, Actually Heraclides is the genus name for the thoas group (the type species of Heraclides is Papilio thoas). If you are going to split the glaucus group into another genus it would have to be Pterourus (type species Papilio troilus), and as Pterourus is the older name it has priority over Heraclides. As I have pointed out elsewhere on the forum, at best Pterourus should be regarded as a subgenus of genus Papilio, encompassing the glaucus group, 'Chilasa', elwesi, alexanor and 'Heraclides'. All the rest of genus Papilio belongs in subgenus Papilio (including 'Princeps', 'Achillides', Menelaides' and others). In reality these so called genera are nothing more than glorified species groups. It should be remembered that the genus name serves an important purpose (or should do) in helping non-experts to know which species are related to each other. Over-splitting only hides this information from other users of the names, and thus imparts less information to them. Adam. |
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