Hi, taxonomy and DNA barcoding should be tightly interlock.
Both research fields are very important.
Cheers, Nadine
In my mind the future of taxonomy is on applying different methods or approches (so called polypasic approach). The improvement of some new methods can't cause full rejection of the classic and traditional methods or techniques. These are located in different areas of use, based on differen principles and able to give us absolutely different kinds of data. As for barcodind - it is the techique for only species delineation (but nowadays not always successfull). But we have no efficient barcodes for very and very huge amount of species. Some species can cause very big problems with it's identification through barcodes. But for at least phylogeny constructing to know ways of evolution DNA barcoding isn't good to use.
You must to note that the main aim of taxonomy is unambiguous identification of any organism. In some cases we can to reach this aim only by processing different data from different metods. In general if we can provide pricise identification by morphology or anatomy, we'll do this as a cheaper methods. If we can't identify object by such methods, we use molecular genetic approach and so on. But the best way is to combine different methods.
You also can find the discussions of similar questions from different authors on ResearchGate
Best wishes
As I can judge on current systematic of the Euonymus genus, traditional taxonomic markers and approaches are not comprehensive and cannot provide us unambiguous answers about taxonomic position of given species.
Question is of course too, if the traditional taxonomy will die out sooner or later, because there is a lack of taxonomists working with "traditional" methods.
In my point of view both fields are complementary. The knowledge of the morphology of a specie is necessary in order to begin a study of biodiversity and identify closely a specific taxon, however , sometime can result in a problem specie or Cryptic species, so in this case is necessary to use molecular tools. In this way both field are complementary.
@Traditional taxonomy is very important. Traditional taxonomy is used to identify the species. Molecular and other techniques are used to confirm the traditional findings about the species. Traditional taxonomy is basic and very important for plant biologists and researchers. Yes., the number of people working on traditional taxonomy has reduced. Researchers are in search of alternate methods to identify the species with latest technology. But i am of the opinion that traditional taxonomy must be kept alive and other techniques may be used for its authentication and improvement.
I would agree with everyone that believes that taxonomy is still important. Not only is this useful for identification, but studying the characteristics of a particular species could help bring a better understanding to the environmental conditions that brought about change. For example, what environmental conditions resulted in several species of birds (penguins) to adapt to swimming in a cold environment. With so many species yet to be discovered, taxonomy would be the first step in species identification.
I found an article relating taxonomy and bar coding that you may find interesting at
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0021326
The boundaries of these methods considered separately gives the correct answer.
The future of taxonomy is addressed toward an integrated approach that merges both traditional and new methods. Taxonomy is not died. Taxonomy should be only reconsidered and progressively integrated with the new methods and then applied to each specific context. A good knowledge of the ecology of the specie and of its hystory, also related to the environment, can help in this process.
Only in this perspective, we can more easily detect the increasing biodiversity.
In my opinion the taxonomy is more or less the same, it is whether we use morphological characters or molecular characters that differs? Unfortunately morphological methods have become less popular due to the more extensive learning it requires to become a good taxonomist within a certain organism group. Molecular methods are easier to learn and since they are more or less the same for all organisms they don't require deeper knowledge about a certain organism group. Hence there is a notion that instead of a number of "traditional" taxonomists you can hire a molecular taxonomist instead. They are of little use however unless there are identified specimens to compare the barcodes or sequences to, then they are a great complement to morphological methods.
The taxonomy is the same but some techniques and tools are being invented, improved, modified and replaced according to the changing requirements of the time. With the advancement in science, technology and our understandings, almost every discipline of life has adopted latest methods, techniques and technologies and this is natural and an evolutionary process. No matter how much advancement is attained in systematic, the traditional taxonomy will be indispensable and will run parallel to molecular taxonomy. Because for initial assessment and identification in the field, one must be familiar with morphological parameters.
However, in most of the cases, traditional taxonomy is in practice mostly by those working for EIAs and IEEs whereas; researchers prefer mostly to collect some blood / skin / fecal material sample in the field and get them analysed in the labs. Therefore, traditional taxonomy will also be in future and traditional taxonomists being less in number, will be more important.
My point of view is in favor of traditional taxonomy. Molecular technique provide tools for better understanding of certain topic, such phylogenetic evolution, but not all can it do with a molecular approach. We can not describe a species only with it COI. What can we do with all the holotype and material deposited for more than 100 years in museums? We can not destroid it trying to extract DNA.
Barcoding is not the "philosopher's stone" for taxonomy. It is just a tool; of course an important tool. Traditional morphology-based classical taxonomy should not be discarded at all. Rather, it should be used together with the more modern molecular and biochemical techniques. The current problem is that, on one hand, each housewife is able to do a PCR; on the other hand, classical taxonomists are "species in extinction".
There will be a need for traditional taxonomy describing external and internal morphological and anatomical traits also in the future, e.g. how to put fossils in a phylogenetic frame? How to understand the biodiversity in an environment not knowing which species occur in this environment and not being able to identify them properly? Not forgetting that we are humans generally communicating with our languages. We want to give names to everything and we have to do this. Otherwise we cannot communicate successfully. To do so on a scientific way we give, since Linnean times, one scientific name to a species. Of course it is an artificial system which has to be adapted continuously – and which is done since then. Nevertheless, to be traditional means to take care of the fire and not of the ashes.
Before there can be conservation, management and appreciation of any of our natural resources, there must first be recognition and identification of organisms found in areas of interest, be it a backyard, state, country or the world. This cannot be done without traditional taxonomy, and training future scientists to rapidly and accurately classify and identify unknown organisms is essential and critical to our future well being as humans.
From my point of view molecular taxonomy is very useful to try to resolve ambiguities, although sometimes it generates another ones. Nevertheless, molecular taxonomy has revolutionized the tree of life. However, molecular taxonomy rarely contributes to an understanding of the evolution at the adaptation level. I have an open question about the evolution of the Fabaceae flower, I invite all of you to participate. This is an example of how molecular taxonomy is changing our point of view of the phylogenetics: lots of changes have been accepted in the phylogenetic trees, but little information is added to explain the consequences of these changes to the evolution of the group.
https://www.researchgate.net/post/What_about_the_evolution_of_the_Fabaceae_flower
I think the key word which some have used previously is that DNA barcoding is a tool. You can use a tool correctly and you can use it incorrectly. Will DNA barcoding take over traditional taxonomy? No, certainly not. Molecular tools cannot answer nomenclatural problems, or determine field based characters for identification. I consider myself a traditional taxonomist but I also work closely with geneticists and my belief is the way forward is good collaboration between these two fields. DNA barcoding is great at highlighting where potential species complex issues may lie, but they cannot solve them. The use of DNA barcodes alone to identify a taxon is in my opinion bad practice, but that is based on my personal taxonomy expertise (fish) so I cannot comment on the other organism .
We will have "taxonomists" who are very skilled in performing PCR and sequencing DNA of animals they have not ever seen before in their life. Systematics, Anatomy, Nomenclature, Biogeography, Ecology..... what is it?
Are such Researchers worthy to be called skilled"taxonomists"??
New molecular technologies are foundamental of course, but not an heal-all tool in Taxonomy.
Everything should be used "cum grano salis".
Thank you.
For a number of taxonomic groups and regions, we have not yet passed the exploratory phase. Undoubtedly, the ‘taxonomic impediment’ – the acute shortage of taxonomic expertise has resulted into poor knowledge of global biodiversity, particularly in the developing world. Besides, the funding for conventional taxonomic research is meager in contrast to that is siphoned for biotechnology. In developed world, alpha-taxonomy has reached to a satisfactory, if not a saturation level; at this stage, other modern tools such as DNA barcoding can prove promising. Pertinently, DNA barcodes can identify the already described species but have little impact on the major issue of taxonomically undescribed and unknown taxa. Use of this technology for resolving the taxonomic complexes can be profitable. DAN barcoding can only supplement and never supplant, the conventional taxonomy (Refer to the following articles for more information: Hebert, P. D. N. et al., Biological identifications through DNA barcodes. Proc. R. Soc. B, 2003, 270, 313-321; Ebach, M. C. and Holdrege, C., DNA barcoding is no substitute for taxonomy. 2005, Nature, 434, 697; Dar, G.H., Khuroo, A., Reddy, C.S. & Malik, A.H. 2012. Impediment to Taxonomy and Its Impact on Biodiversity Science : An Indian Perspective -in Proceedings of National Academy of Sciences Sect. B. Biol. Sci.82(2): 235–240).
I see an underlying problem in this question. When talking about 'traditional taxonomy': do you mean that e.g. 'morphology' (in a restricted sense, i.e.: non-molecular morphology) is 'traditional' and other techniques such as e.g. DNA Barcoding are 'advanced'? All parts of Science have made use of methods and ideas that were abandoned after some time, this is normal. Here the question is: will you identify the trees in your garden using a lab kit, or just by eye? Would you go out in the field and record the birds nesting in your area after amplifying samples of their genetic materials? Would you urge all the human population to depend on DNA sequences for such subjects? (Once all the still living species were sequenced by 2093).
So I think that (1) taxonomy is a wide and varied occupation which includes phylogenetics but also other tasks such as identification, and (2) some of our present day techniques will become 'traditional' in one to five decades.
As a fish taxonomist I am very much agree with the views of M.C.Sidhu . DNA bar coding alone is not going to solve identity of an organism but help to solve the ambiguity of misidentification.
here in this article we adress some problems of barcoding...
cheers, Oliver
The "molecular taxonomy" is ONLY ONE SEGMENT OF REAL TAXONOMY, NOT A "MOST IMPORTANT", because in the future other new methods will be used in taxonomical investigations. By this way, description of new taxa based only on "molecular taxonomy" is great error conducting to divide present taxonomy in several taxonomies. The classic "morphological taxonomy" is the oldest one, and all further "taxonomies" must be combined with it.
Morphological taxonomy is basic taxonomy to identify the fish and other modern methods are used to confirm the identity and to clarify the doubts if any.
The morphological taxonomic is essential for the whole natural world. No matter what kinds of technology we use, the descriptions of new taxa are mainly based on the morphological characters. Further, most species can be identified using the morphological characters. Something is changing, something is outdate, but the traditional taxonomy is classic and will be exist throughout eternity. However, to be honest, most taxonomists always stay at a silent corner and are easy to be ignored. I am one of them :)
There have been a lot of discussion about this issue over the years, but truth be told, traditional taxonomy must become more interdisciplinary to survive. Integrating new tools, such as molecular and computational techniques, high resolution photographs, CT scans, etc. will open up new possibilities, such as better chances to get project grants, publishing in journals with higher impact factors, attracting attention of new students or even from funding agencies. Taxonomy is a fundamental science – the foundation in which many other disciplines were built up – but tradicional taxonomy must evolve. New taxonomists will need to master several different skills, from the very basics of preparing and preserving specimens, to advanced molecular and computational tools (DNA barcode is certainly one of such tools, but it will hardly replace taxonomy, which will yet be needed for a long time).
Jhonny: "new tools, such as molecular and computational techniques, high resolution photographs, CT scans, etc. will open up new possibilities, such as better chances to get project grants, publishing in journals with higher impact factors, attracting attention of new students or even from funding agencies". So, according to you, taxonomy to persist, must cease to be a serious branch of science (where tools are selected according to their apriopriateness for solution of particular scientific problem), but transform into "‘academic prostitution’, in which work is done to please editors and referees rather than to further knowledge" [Frey Osterloh 2010]? Nice perspective...
You clearly misunderstood the point I made dear Roman. By interpreting my words like “so, according to you, taxonomy to persist, must cease to be a serious branch of science …” and “work is done to please editors and referees rather than to further knowledge” this becomes clear. I said tradicional taxonomy (works based solely on morphology) must become more interdisciplinary. Or do you really think it is so bad when species descriptions are based on multiple lines of evidence (the so-called Integrative Taxonomy)? Keep in mind that new species are taxonomic hypothesis; the more lines of evidences (morphology, DNA, cytogenetics, bioacoustics, etc) supporting your hypothesis the better; and it certainly doesn’t mean you are gaining less knowledge on doing so, but on the contrary. And as I said before, taxonomy is (and will always be) a very important science, but it doesn’t mean we cannot move from a tradicional approach to a more integrative one. Best regards!
Jhonny: I reacted on what you had written, and you did not argue for applying every relevant kind of evidence in order to increase knowledge, but for applying "modern" approaches in order to increase "chances to get project grants, publishing in journals with higher impact factors, attracting attention of new students or even from funding agencies" - i.e., in the Frey & Osterloh's words quoted by me, "to please editors and referees rather than to further knowledge"...
The worst is the fact, that you, in fact, were right: nicely sounding "integrative taxonomy" is almost invariably interpreted not as using all relevant (whether "modern" or "traditional") evidence, but as obligatory application of "modern" aproaches (even if irrelevant and unnecessary), so that publication of (to say nothing of receiving grant for) taxonomic study based on (in overwhelming majority of cases the only really relevant) morphology is practically impossible. And as, on the other hand, the XXI-century scientists are forced to participate in the "rat race", i.e. to concentrate on collecting citations, impact factors, and other formal "criteria of excellence" instead of maximally effective scientific reasearch, the real scientific value of their studies decreases instead of the claimed improvement!
All the best!
Muhammad: DNA barcoding has, with rare exceptions, nothing or very little to do with taxonomic research: it may only serve as help in identification of species already defined and described by "traditional" taxonomists. Unfortunately, nowadays some scientists try indeed to "cut corners" by defining species based on barcodes, molecular distances, or computation techniques (e.g. "principal component analysis"), having little or nothing in common with the evolutionary species-concept, but such practices are nothing else but transforming taxonomy from serious science to a childish formal game: we could with almost as much sense classify species according to arbitrarily predefined size-partitions (10-12 mm. - species A, 12-15 - B, 15-18 -C &c.), colours, or any other "criterion"!
In general, taxonomy has two main tasks: reconstruction of phylogeny and creation of usefull and operable system of organisms, which use to be syninimized by mistake. Methods based on molecular information are of a great power for the first one, but are in certain extent overweighted by now for the second. The same happened before with other approaches (isoferments karyosystematics etc). Being first much overweighted all those were implemented in taxonomy providing a new set of characters to define and deliniate taxonomic groups. The same is going on now with increase of the number of gens involved in taxonomic analysis and deliniation of groups together with morphological signs (integrative taxonomy, if you like). The curren topology of the tree of life alwais compromize all the awailable characters with different weights for better deliniation of the taxa of different ranges.
Let's wait and see for how long the barcoding will exist? Apparently new technology will be suggested to replace one. Then next one, then next, indefenitively. Identification of OTUs by machinist menthods is not taxonomy, it is a mechanical method which could be used i.e. for taxonomy. A ruller and a measurement are two different things...
No, there is no future. As we approach the description of millions of species, many of which will go extinct before proper description... the task ahead is just beyond human capacity.
Now, not that it shouldn't!
A few thoughts on that:
(1) What is "traditional" or "conventional" taxonomy (a point that Enrique García-Barros has raised before)? I am working on Lepidoptera, and until a hundred years ago, no Lepidoptera taxonomist would have thought of looking at genitalia to distinguish species. Back then, "traditional" taxonomy was mostly comparing wing pattern, wing venation and shape of the palps. Today, I would not rely on these character sets any more for species discrimination, as we know now that they can be rather plastic. The set of tools for taxonomic studies is constantly expanding, or at least changing, and "traditional" becomes a blurry term.
(2) What is the current role of DNA barcoding in all this? Well, DNA barcoding is, as stated by others before, a tool. And it is mostly a tool for non-specialists of a certain group of organisms. For example: I know pretty much nothing about staphylinids. If I was to identify a batch of Staphylinidae beetles, the easiest way for me would probably to DNA barcode them. But what would I get from that if there wasn't a group of dedicated taxonomists who are experts on Staphylinidae, and who have built a DNA barcode reference library, who have identified all those specimens in that database so that I actually get matches for my DNA barcoded specimens? And these Staphylinidae experts have to use the entire range of identification techniques (i.e., all of the useful tools from "traditional" taxonomy, plus DNA barcoding to create a connection between DNA barcode sequence and the Linnean name) at their hands to create a high-quality database for staphylinid DNA barcodes. Without a well-curated DNA barcode library, maintained by experts in their field, DNA barcoding would be worthless and a waste of resources. So, in my opinion, DNA barcoding is not a threat to ("traditional") taxonomists. And neither are next-generation sequencing approaches. It's just an extension of the tool set. You still need the people (taxonomists) who know how to use them.
Richard: "DNA barcoding would be worthless and a waste of resources. So, in my opinion, DNA barcoding is not a threat to ("traditional") taxonomists" - it should not be, but unfortunately it is: it is next to impossible tu publish a traditional taxonomic paper in "high IF" journal (and only such journals "count" in evaluation of a researcher...), it is next to impossible to receive a grant for traditional taxonomic paper, &c., all under the incredibly stupid but overwhelmingly influential "ideology" that traditional taxonomy is a "XIX-century philately" and only molecular studies are sufficiently "modern"!
DNA bar coding has nothing to do with classical taxonomy there is a lot of miss use of DNA barcoding for identification of species evev without seeing the taxa. It is Just a modern tool which can help in confirming the taxonomic status.
Si no hay un taxónomo clásico que identifique las especies, los moleculares no pueden hacer nada. Los seres se identifican en la naturaleza por sus caracteres visibles. Sin personas que identifiquen no se pueden realizar estudios ecológicos.
La sistemática molecular se basa en postulados, que no es lo mismo que ha ocurrido en la naturaleza.
Taxonomy is identifying organisms. Quick and easily executable way of identifying an organism is using morphological characters or traditional taxonomy. What ever modern techniques get invented in the field of taxonomy still the basic and first step will remain the most important and basic technique in taxonomy. All other techniques either chemical or molecular will act as a supporting tool in the field of taxonomy. one can not rely on bar coding until and unless that organism is identified on the base of morphology. once morphological character differences are confirmed then the second step will be moving towards the molecular techniques. remember even in molecular techniques markers vary among groups. like even barcoding can not explain genetic variability in certain groups of organisms. recently in a study conducted by my phd student we have observed that DNA barcoding region does not explain the phylogeny and variability but other markers can. so where ever we go traditional taxonomy is important and will remain important. the sad part is that traditional taxonomist are decreasing and molecular taxonomist are increasing. with the decrease in traditional taxonomist there will be no one to help the molecular workers in identifying the organisms.
Please follow the link below for an integrative approach.
Article DNA BARCODING AND TRADITIONAL TAXONOMY: AN INTEGRATIVE APPROACH
The number of people working on traditional taxonomy has reduced. Researchers are in search of alternate methods to identify the species with latest technology. But i am of the opinion that traditional taxonomy must be kept alive and other techniques may be used for its authentication and improvement.
The synergistic use of both methods, in the form of integrative taxonomy, has the potential to contribute to biodiversity conservation in a pragmatic timeframe and overcome their individual drawbacks.
Thanks
Estoy totalmente de acuerdo con Eduardo Marchesi: sin la taxonomía clásica, la taxonomía molecular no puede hacer nada bueno.
De hecho, he visto unos cuantos trabajos moleculares que carecen en absoluto de validez, precisamente porque los ejemplares usados en el estudio están mal determinados.
I totally agree with Eduardo Marchesi: without classical taxonomy, molecular taxonomy cannot do anything good.
In fact, I have seen a few molecular works that are completely invalid, precisely because the specimens used in the study are badly determined.
May I invite you to the discussion I want to initiate on turbo-taxonomy:
https://www.researchgate.net/post/Is_turbo-taxonomy_the_solution
In this paper we share some thoughts on traditional taxonomy in a changing world:
Article When mycologists describe new species, not all relevant info...
The biggest problem with barcoding in my opinion is that errors may stay unnoticed in the BOLD system and can cause future problems if used for identification.
I am attaching a recent paper of Adriana Radulovici and me where we give some examples on problematic cases.
The issue is of course, what do we mean with classical or traditional taxonomy. Taxonomy has evolved since the establishment of taxonomic studies as part of the research curriculum. The taxonomic framework considered by Linne and other founders of early taxonomic research was rather distinct from taxonomic work today. Incorporation of new concepts such as evolution instead of stasis in species concepts besides integration of expanding evidence obtained by new methods was crucial for the progress of taxonomy. Ignoring scientific progress for example the transition of taxonomic research towards big data science will result in stagnation. Basically, early stage researchers have to decide if they want to be part of the stagnation or parts of the avangarde that integrated traditional knowledge with modern science. In short, I am not convinced that the basic assumption of a conflict between old fashioned taxonomic research and progressive taxonomic research exists. Instead of wasting our time with discussion about eh failures of taxonomy in the past, we need to focus on the discussion how taxonomic research can contribute to the challenges of the 21st century. Sticking to concepts that have a poor record is usually the best receipt to collapse. Thus, taxonomist need to focus on adaptation and progress instead of stagnation.
both the classical and molecular classifications have their merit and demerit. As long as human activities is involved in a process in whichever way, what you can only have as a result is near perfection and not a absolute one. As suggested by Harald, it would be in our best interest as taxonomist and that of our communities to rather begin to concentrate on plant adaptations, preservation from extinction.
As I see it the question here has nothing to do with the importance or usefulness of taxonomy. It must be obvious to anyone intellectually honest that without accurate species concepts or correct species determinations any biological study becomes inherently flawed. Also very importantly, any attempt at conserving biodiversity becomes bogus. The actual "problem" with taxonomy stems from completely inadequate (not to say plainly stupid) scientometrics in current usage, which are effectively stifling some fields of science that don't play well along with their citation mechanics, of which taxonomy is just one example.
How i see the question, the main problem in traditional taxonomy is traits choise and its interpretation, which greatly depend by the researcher experience, opinion, etc. Numerical estimation (as morphometry, colors composition) could make interpretation more objective, but still remain question of the data elaboration and, especially, how to estimate which traits are more important in the multifactorial analisys (and how define a single trait if we took them all as having same importance). Estimation of the variability of the each trait, traits correlation (for detect traits independence), normal or abnormal distribution in big pool of data could partially provide the reference points of the traits interpretation, and in this case, phylogeny should provide another one, as a "frame" of the study: building ever simple phylogenetic tree or DNA-barcode table, traits could be reconstracted phylogenetically and then could be estimated which changes are casual and which not and more stable phylogenetically. Also, molecular comparisone could easely resolve what is ecologycal or seasonal forms and what corresponds to the genetic variability. By this way traits could be selected and then combined into morphologycal analysis.
The conventional taxonomy is still really important in the future as its a very fundamental way to recognise, identify and classify the species but still, we cannot just rely on this method only to analyse our data and then finalise the results. Molecular and any other aspects are so important as additional proof to help so many taxonomic problems that the conventional one cannot solve. And later, we also cannot just rely on molecular techniques. Each has its own advantages and disadvantages. We must accept and practice both methods. Integrate the knowledge without any bias to get the best output.
Traditional taxonomy is the basis of molecular studies. If we don't know the system we can not do the further study. Even for the barcoding one should be perfectly aware of taxonomy and the systematics of the particular organism. If you don't know the correct name and taxonomic position of the organism, to whom you will designate the barcode?
“The beginning of wisdom is to call things by their proper name.”― Confucius.
Traditional taxonomy is probably the first step in Biological studies that is underlined above in the proverb. There are several advantages of traditional taxonomy over molecular one but this does not mean to ignore molecular taxonomy. I think as long as we know what we do (and respect each other field), it is okay to use both.
Rather than discussing about dis/advantages of traditional or molecular taxonomy, we may focus on how many individuals (specimens) necessary to describe a new taxon (or taxa) or a species. Any comments on it?
I also consider that traditional taxonomy has not been lost, but I do consider that few works based on traditional taxonomy are seen because many journals ask us to carry out molecular studies. It is no less true that in some cases it is necessary to use molecular characters to elucidate a problem, but for some taxonomists it is very difficult to obtain funds to carry out these studies.
Traditional taxonomy will never be lost, although many do not recognize it, it is the basis of all types of study.
That is correct. I aggree that traditional taxonomy is probably the first step of all. I suggest to consider Turkish Journal of Zoology for a possibility of your future taxonomy based work (and let me know when you do it). It is free of charge.
As many stated, traditional taxonomy is and will remain important. There are taxa, where DNA barcoding has not brought any reasonable results, while ecologically and phenotypically these organisms are definitely known as separate species. Also it is impossible to neglect the importance of the phenotype and refer just to genotypes and markers. Ecologically phenotypes are highly important to understand reproduction biology, habitat, lifestyle preferences, etc. - and they cannot be neglected. Decision making of phylogenetic trees would be hardly possible without knowledge of classical taxonomy!
When science enters into the era of Big Data analysis (CE 2000 onwards), both molecular (based on objective data) and classical (based on subjective data) approaches should be given equal importance when arriving at a meaningful species concept. Morphology can be used as the first tool in systematics.
Yes, the traditional taxonomy is a very important,
Molecular and morphological methods are working together useful to determine the characterizations of species
Molecular methods are confirm the identification and also some for identification as quickly to continue in researching
In my opinion, the traditional taxonomy (Morphotaxonomy) is key and should be the first step to identify an unknown species by following the principles of taxonomy. No doubt, other tools like DNA barcoding (so-called Molecular taxonomy) have their own importance to facilitate the accurate process of species identification especially in complex taxonomic problems like cryptic/sibling species complexes. It is very necessary to integrate both morphological and molecular approaches to resolve such problems related to species complexes to obtain authentic and accurate taxonomic results.
I suggest a new article about the subject by Engel et al. 2021 "The taxonomic impediment: a shortage of taxonomists, not the lack of technical approaches"
Although traditional taxonomy is insufficient in some cases, it is indispensable for the identification of species. It is obvious that molecular methods are useful in cases where it is necessary to detect hidden species or in the separation of species that are morphologically very similar to each other. On the other hand, there will be difficulties in distinguishing a species identified only by molecular methods in practice by other researchers. In this case, the most accurate method is to conduct studies that have been examined by traditional morphological methods and whose accuracy has been proven by molecular methods. Unfortunately, molecular methods are difficult and expensive for scientists in developing countries.
Both methods, DNA barcoding as well as traditional taxonomy, rather complement each other. New species still need to be described following "Eatonian" criteria, i.e. foremost adult males and females, larvae in some cases. In the case of aquatic invertebrates, it is not unusual to find many more different taxa with DNA metabarcoding than with standard sampling protocols - but this might be due to the fact that most samples are not identified down to species level, or are based on larval material that has often simply not yet - or never has been - identified to species level. However, if your goal is, ideally, to find the whole range of species within a given biotope (e.g. springs, wetland, rivers etc.) you most probably find more than what is available in DNA barcode libraries, because DNA sampling in wetlands or springs is much more complicated, for lack of protocols.
DNA results provide a "flat" list of taxa. If you attempt to use this list for conservation purposes, you have to find not only the corresponding material specimens (known or cryptic taxa) for a formal identification, but also discover their ecological requirements. DNA barcoding thus is very helpful for discovering overlooked biodiversity hotspots, but the final burden of describing the material rests on traditional taxonomy.
Traditional taxonomical methods consider the visible fitures while molecular methods the invisible. It seems that in any taxonomical method the features that distinct is the point. Does every gene brings out certain distinction? How about the 'non-sense' genes, or those 'silent'? Or perhaps some genes in 'degeneration' that they may be good indicator for now but invisible in the furure? Maybe someday traditional taxonomical methods will merge with molecular methods，trully point out the taxonomical features.
DNA barcoding is a practical and efficient method, which can be used if the database is filled with sequences of reference specimens.
As for the traditional method, it is unavoidable because of the presence of continuous mutations and polymorphisms in the species ..... the two complementary methods
There is definitely. As long as it keeps up with technology (computer-connected microscopes, artificial intelligence technology), why not?