Taxon names published in theses and dissertations do not satisfy the requirements of the International Code of Zoological Nomenclature to be available, in the sense of the Code. The dissertation name is unavailable, and can hence not be valid. For all intents and porpoises that name does not exist.

According to my understanding a new species name has to be officially published either in a magazine or book. Species names used only within dissertations are taxonomically valid (compare Bonelli, F.A. (1826) manuscript only).

I agree with Riaan that the name is not valid. If memory serves, all species descriptions must be published in a peer-reviewed source/journal with subscription/circulation greater than 100.

Sorry, there is a lapsus. Please, read "are taxonomically invalid".

>> published in a peer-reviewed source/journal with subscription/circulation greater than 100

No, the ICZN has no requirement for the circulation size of a source to make a name therein published in the sense of the Code.

I would say that names published in theses and dissertations can be valid. I can't see what requirements in the Code that a dissertation do not satisfy.

I should add, that my answer only applies if the dissertation has been printed

The answer to your first question is found in the International Code of Zoological Nomenclature (by ICZN = International Commission on Zoological Nomenclature). They rule in Article 8, " what consitutes published work" that, among other criteria, 8.1.1 it must be issued for the purpose of providing a public and scientific record (that is obviously met in the case of the thesis), and 8.1.3. it must have been produced in an edition containing simultaneously obtainable copies by a method that assures numerous identical and durable copies. In my eyes a thesis meets this criterion as well, being available for multiplication in a named public library. The name can also be disclaimed in the thesis - in my country this is common, if a thesis contains manuscripts of works containing nomenclatoric acts that are really intended to be later published in a journal. But the disclaimer must be explicitly stated in the thesis. There are better specialists around in ResearchGate, including the Secretary of ICZN who can, and hopefully will, further enlight us all. There are other demands also that need to be met, and I suggest that you dig into the Code for them (some of them are dependent on the publication year of the thesis and other criteria for which your question does not give enough particulars, for me to be able to evaluate the case further). The Code can be obtained from http://iczn.org/code.The second question is straightforward: you should not name the extant taxon if the already existing one is available, i.e. meets the rulings of the Code, unless you can argue that your beast indeed is a different taxon - that how you do this is a matter of opinion and is therefore not strictly scientific. But, if your reasoning looks unconvincing, your name will likely be sunk into synonymy by your colleagues sooner or later.

>>> Secondly, when naming the new (extant) species do we need to prove that it is morphologically distinct from a taxon that lived in the same region 70,000 years ago?

Exactly the same requirements pertain here as if you were dealing with two taxa living side by side, contemporaneously.

** Are these taxa two species of the same genus? Then you will have to show significant differences between them, or else risk creating a synonym.

** BUT if the first taxon exists only in that dissertation, and its name is not available in the sense of the Code, you may safely ignore it, on nomenclatural grounds.

** BUT, for taxonomic reasons, is the taxon that exists only in that dissertation a real species entity, but hitherto unpublished as such? You will have to address this possibility, and refer to the (sub)fossil teeth when describing your new species. It may even turn out that you are have to describe TWO new species!

The basic question is if the dissertation was published or not. If it was published in any way (since 2012 even electronically), and complies with the other criteria provided in the International Code of Zological Nomenclature, then the name is available.

Availability does not depend on peer review.

Validity, on the other hand, is a question of taxonomic judgement. A name may be available but not necessarily valid.

The Code states unequivocally the criteria for "publication" and these criteria include neither peer review nor the circulation of the journal. Lately modifications have been introduced to accommodate electronic publishing, but the fundamental requirements remain unchanged. Article 8 of the code states that in order to be "published" a work must be issued with the intent of providing a public and permanent record, obtainable free of charge or by purchase, and produced in an edition containing simultaneously obtainable copies by a method that ensures numerous identical copies. Before 1986, the work has to have been published on paper, but after 1999 copies of a non-paper work ( such as a CD) must be deposited in at least 5 major public depositories which are named in the work itself. Since most dissertations do not meet these criteria, names published in them are not valid or available--in other words, they can be ignored. Ambiguous exceptions would be theses that have actually been printed, such as is required by some European universities (for example, in the Netherlands) before the thesis defense. These theses would most likely meet the criteria for publication and any new taxon names proposed in them would be both valid and available. As to the distinction from a 70,000 year-old species, that would be entirely up to the discretion of the authors so far as ICZN is concerned.

It is not a simple issue. The ICZN requires to have the name published (not necessarily in a peer reviewed book or periodical) but it gives criteria of what should be considered as 'published' or not. Some theses are clearly not published and the names are then unavailable. Other theses are clearly published (e.g. some have an ISBN) and then the names are available. Finally for some theses the situation is not clear at all and you have to check one by one all the criteria of publication given by the ICZN. I know the case of several names of amphipod crustaceans published in a thesis, which are accepted by the community of amphipodologists, but which I suspect to be unavailable (unfortunately I have never been able to see that thesis).

In order to remove any ambiguities, the ICZN recommends to write a statement in the thesis that it should not be considered as published. That is what I did in my own thesis (which includes new names and which is available on researchgate) in stating: "This thesis is not issued for public and permanent scientific record and for purposes of zoological nomenclature. Hence it is not published within the meaning of the International Code of Zoological Nomenclature, 4th edition, article 8.2. New names and nomenclatural acts included in this thesis will enter in force only at the time of their publication in the relevant scientific periodicals."

Peer-review is not a request by the Code, as W. Shear mentioned. The first thing to solve this case, whetever answer you read from us colleagues, is to read the Code in detail! It is available online and does not let much room for interpretation.

Thesis is not a publication. Therefore a new name cited in a thesis is not a valid name.

Excellent feedback from all of you and many thanks for spending time on this. This is giving me great insights on what needs to be done next. The dissertation was published in 1994. I saw a paper copy once but that one has disappeared. The author wrote to me saying that he has lost the dissertation himself. There is a microfiche copy in the UC Davis library but a professor there wrote to me today that it wasn't straightforward to obtain. By the sound of it, this suggests to me that the name may not valid then, i.e., it isn't in a peer-reviewed format that can be easily accessed by the public.

As to proving that indeed the extinct taxon is different from the present one, this introduces the challenge that we can only look at molar teeth (it is a primate we are looking at). Molars in all similar species have declined in size since the Late Pleistocene, so even if we did find a difference it would not necessarily tell us that much about taxonomically relevant differences between the extant and extinct populations/taxa. An additional problem is that the molars cannot reliably be distinguished themselves (especially M2 and M3), so it might be hard to compare them to extant materials and get any reasonable conclusions.

Phylogeographically it would actually make most sense if the extinct taxon and the extant one are the same. But then if the originally name is a nomen nudum, we could assign a new name, and provisionally include the Late Pleistocene taxon in that same new species, although I guess we would then have to convincingly show that they are indeed the same. Complicated stuff, but all exciting.

Some (a minority of) theses are definitely publications.

I agree with Olivier that the Code has to be read. However, according to my experience, even in reading the code very carefully, some issues remain very difficult to solve.

Read ICZN's chapter 3, article 9 -- generally it is not constitute a published work (for zoological nomenclature purposes). There is an example about Ph.D. thesis: "A Ph.D. thesis that was distributed only to members of the student’s thesis committee is listed for sale in the catalogue of a print-on-demand publisher. The print-on-demand work is a reproduction of the thesis. Because the thesis was an unpublished work in its original form, it remains unpublished. If an editorial process was evident in converting the work to print-on-demand form (e.g., change to single spacing, repagination, addition of running headers), it might be considered published."

At least here in Chile, all PhD thesis work must be published previous to public exam, therefore that work is peer-reviewed. In botany, a name for new species is valid when you have a valid (and in latin) description for that species, regardless the translation for that description in english or any other language. And that must to be public (or, in other words, published in a peer-reviewed journal)

No, a dissertation is not considered a scientific publication, because their range is limited. Soon, these species names are not valid.

See Chapter 3: Criteria of publication - Article 8. "What constitutes published work" of the International Code of Zoological Nomenclature (http://iczn.org/node/40200).

Considering the circumstances about the thesis you described, it seems that the name of the taxon in concern is not available and hence not valid, likewise, regardless the thesis was once deposited, but not in a way that would prove it is published in a sense the Code issues. Considering the other matter, the sufficient level of differentiation for the establishment of the new, distinct species depends on the overal variability in the genus to which it belongs, as well as on the intraspecific variability, i.e., the relationship of your material to other populations. Phylogenetics would remarkably add to the reliability on the decision of the species status. The precautiousness related to the uncertainty about the position of molars and their difference only oin size you declared seems justified, if there are no differences in states of other characters relevant for the species in concern.

True, a dissertation or a thesis is NOT a publication... That's it... Therefore a new proposed name of a new species should be published in a journal. Contents of the thesis or dissertation whether containing new species or not should be published to contribute to new knowledge.

A thesis will be a publication when it is published by a publisher, and so to make it available to the public.

Taxon names published in theses generally do not satisfy the requirements of the International Code of Zoological Nomenclature and are thus, unavailable.

Thank you all for your interesting comments, since the introduction of new names in theses is a problem, which disturbs me for years. As concerns the case considered herein, it is clear for me that the thesis should not be considered as published and that the name is not valid. However it must be pointed out that the printing/edition/distribution system of theses is very variable from country to country and I think that each case should be considered separately. Anyway, in order to remove any ambiguity, when introducing new names in theses, I think that it is strongly advisable to write a statement that the thesis should not be considered as a publication (as I did in my own thesis).

You need to refer to the International Commission on Zoological Nomenclature iczn.org/‎ - the answer may be in their International Code of Zoological Nomenclature www.nhm.ac.uk/hosted-sites/iczn/code/‎

The International Botanical Code mentions theses. "30.8. Publication on or after 1 January 1953 of an independent non-serial work stated to be a thesis submitted to a university or other institute of education for the purpose of obtaining a degree does not constitute effective publication unless the work includes an explicit statement (referring to the requirements of the Code for effective publication) or other internal evidence that it is regarded as an effective publication by its author or publisher.

Note 4. The presence of an International Standard Book Number (ISBN) or a statement of the name of the printer, publisher, or distributor in the original printed version is regarded as internal evidence that the work was intended to be effectively published."

So it seems that a description in a thesis can be valid (for plants, algae and fungi) if the thesis is properly published. http://www.iapt-taxon.org/nomen/main.php?page=art30

Dear W. Shear,

You write quite right: "Article 8 of the code states that in order to be "published" a work must be issued with the intent of providing a public and permanent record, obtainable free of charge or by purchase, and produced in an edition containing simultaneously obtainable copies by a method that ensures numerous identical copies. Before 1986, the work has to have been published on paper,(...)

But, I still see not why these requirements would not, in principle, have been met in the case of the dissertation in question here. However, I see the point made by Cédric, and, combined with the further information from Erik Meijaard, it seems that in this particular case the thesis dated to 1994 can be overlooked.The idea by Colin, to ask the author of the thesis as a co-author, is laudable.

Dear Pedro R, Inocencio, Mohamed and Suresh,

A dissertation can be a valid publication that meets the criteria of ICZN, as pointed out by Cédric (see above) . The 'criterion' that a thesis, per se, or because its range is limited, is not a publication, are dangerous generalizations being potentially misleading and wrong. The nature of a thesis varies depending on the country or institution, and that may make a crucial difference on its availablilty as a nomenclatoric source.

True, the Code may not be an easy reading, but nevertheless of vital importance for anyone who has to make any nomenclatoric acts.

Yes, species described in dissertation are not considered valid till published in peer-reviewed journal

It should also be kept in mind that the rules of the Botanical and Zoological codes are not the same, and sometimes quite different.

There is an ICZN mailing list where questions like this may be discussed.

You may subscribe to the mailing list, submit questions or discuss, using the following link:

http://list.afriherp.org/mailman/listinfo/iczn-list

I agree with the above peers. New species should be published in peer-reviewed journal and only then can be used. Dissertations are not considred as published work

Let's not stray from the point that formal publication as specified by ICZN is the criterion, not peer review. Also, the mere fact that the work is a dissertation does not rule out the validity of the names. What counts is how the work was PUBLISHED.

Please, everyone, obtain and read the Code.

Robert, I don't understand what you are talking about. This is not a question of ethics. It is a question of the availability of the names. The names are not available unless they were published in a way that meets the criteria of ICZN. It would seem from what Erik has written that this particular thesis was NOT published in this way and therefore the names are not available. It would become an ethical question if Erik chose not to make any reference to the thesis or made no effort to contact the thesis' author. He has behaved perfectly ethically (and indeed has gone the extra mile) in this case.

Erik is free to publish a name for the new taxon provided that, in his judgement, it is a distinct entity from any other.

a new species unless published in a peer review journal is cosidered not valid, as the said species cannot be throughly scrutinised at the dissertion, so one must keep in mind when describing a new species to adhere to the ICZN code.

Again, people, peer review is irrelevant.

I agreed with Shear, peer review is irrelevant. When a name is published it becomes available and valid. If the subsequent author reviews and says that the name is a homonym or a synonym, then it is no longer valid.

It is fun, and sad at the same time, to see that most of these comments simply miss the point. Peer-review has nothing to do with the validity of a name. The only rules to consider are the rules of the International Code of Zoological Nomenclature.

Clearly, if you don’t have a copy of the Code in hand, do not contribute to this topic.

There were, however, some excellent contributions. I will vote up all of them.

I am attaching an open-access PDF of the recent amendment of the ICZN for electronic publications "Amendment of Articles 8, 9, 10, 21 and 78 of the International Code of Zoological Nomenclature to expand and refine methods of publication". As you can read, there is nothing about peer-review, as expected.

The attachment!

Just to give a few information concerning publishing of theses - I can only speak for German theses: The diploma theses are generally not published, they get reviewed by two reviewers and will afterwards be stored in an archive of the auditorial office (Prüfungsamt) of the university. I have no information about the Master theses but I guess it will be the same.

The PhD theses on the other hand have to be published, either on paper (certain amount of volumes for libraries), OR on paper (local libraries) and electronically (via library internet data bank, open access and stored infinite) OR on microfish.

So, I guess, the question what kind of theses are providing valid data concerning naming of species depends on the country.

Oh yes, and referring to the comment of Jean-Lou Justine, also on the date and the requirement of registering on the Official Register of Zoological Nomenclature (with ZooBank as its online version).

I wonder where do you, Sam, think published printed work was stored before internet and electronical data bases - in libraries. And also today the journals only fulfill the creteria of rightful publishing if they give some printed volumes to libraries for infinite storage. The dissertations in our country are stored in state libraries (next to others) where everyone can order them. The same state libraries have the open access data bank for dissertations. So, what is the creterium in your opinion that is not fulfilled to be a "real" publication?

I have a similar situation with a submitted paper, a country record which would be new but it is already published in a dissertation. I have received this dissertation via email from a colleague which got it from the university. The dissertation is known among taxonomists working with this group, and they know where to get it. I consider the dissertation as published, not in the author’s desk anymore, available to the scientific audience, treating the record as new would be really poor. What would be the deal? Making it available to experts that already know it and people that will never know? What for, to get a higher researchgate score?

Dear Sam, how do we know in which form the dissertation Erik is talking about is accessible? It appears to be accessible in any form, at least it meets my criteria for being published. When you feel comfortable to consider it unpublished... It’s such a small step to "make it published" – Just put the dissertation on any webpage - it would be published according to the code.

I would say Erik, at this point you should let us know in which form you got access to this dissertation to answer your question more adequately.

Anyway, to me it would be plagiarism to use the name, clearly an ethical issue. There has been some creative input. To me there is more than the code. You should consider that the code is a recommendation, done by humans, subjective, in process, changing over the time, evolving and not implying that you are free to do what you want to do in case a special case is not covered.

So what’s next? Erik is using the name and at the same time he has to name the species described in the dissertation because the taxon needs any name.

Dear Dr. Shear, you wrote: "It would become an ethical question if Erik chose not to make any reference to the thesis or made no effort to contact the thesis' author." This is absurd. First, I know you could cite unpublished work, however, it does not make any sense to me because I can’t check the reference and verify the content because it’s not published. Then, how would the effort to contact the thesis author look like? "I know you worked several years for the probably most important academic work in your life, however, sorry, it does not meet the criteria of the code and I will take the name to name another taxon and put my own name to name the species you described in your dissertation because it has to be named anyhow? Are you okay when I am going to slap in your face twice?"

It might be indeed a different situation when the thesis author agrees, is directly involved and becomes co-author. Well, he has to proceed in university anyway...

Erik, would be great to know if you have already contacted the author of the dissertation.

I know here are some people believing in selfish genes. You might defend something here you have already done before. Of course scientists more involved in administrative things than in gathering data could profit from unpublished dissertations of students they administer. It might make you better scientists, but not humans. However, I believe in altruism, and I am not going to spend further time in this discussion. Have to describe some new species.

Here is Appendix A of the code, the "Code of Ethics". From my point of view there is a general trend that says: Erik, be nice, be fair, be creative and find your own terminus for naming the new species.

1. Authors proposing new names should observe the following principles, which together constitute a "Code of Ethics".

2. A zoologist should not publish a new name if he or she has reason to believe that another person has already recognized the same taxon and intends to establish a name for it (or that the taxon is to be named in a posthumous work). A zoologist in such a position should communicate with the other person (or their representatives) and only feel free to establish a new name if that person has failed to do so in a reasonable period (not less than a year).

3. A zoologist should not publish a new replacement name (a nomen novum) or other substitute name for a junior homonym when the author of the latter is alive; that author should be informed of the homonymy and be allowed a reasonable time (at least a year) in which to establish a substitute name.

4. No author should propose a name that, to his or her knowledge or reasonable belief, would be likely to give offence on any grounds.

5. Intemperate language should not be used in any discussion or writing which involves zoological nomenclature, and all debates should be conducted in a courteous and friendly manner.

6. Editors and others responsible for the publication of zoological papers should avoid publishing any material which appears to them to contain a breach of the above principles.

7. The observation of these principles is a matter for the proper feelings and conscience of individual zoologists, and the Commission is not empowered to investigate or rule upon alleged breaches of them.

Sam, of course, its not a problem when somebody who is acting ethically (like you) is dealing with such subjects, all good suggestions. However, it could be a test case for people that simply look for weak points in the code to take advantage of "unpublished" dissertations, making two cases out of one, a disaster for PhD students just to increase the academic record.

Well Sam, after reading it again I really like your approach outlined above, it solves the problem in a reasonable and ethic way. Definitely a vote!

Dear all,

Again many thanks for all your input and advice. Just to clarify a few things further. I have been in touch with the author of the dissertation and he will certainly be involved in the final naming of the species. He admits himself that his thesis is not readily available, and that his name may be a nomen nudum. He has lost his own copy, another copy (which I saw myself) was kept at ANU in Canberra, but that has also disappeared. Apparently, UC Davis has a copy on microfiche, which may be the only copy that is now available.

I am working with a team of conservationists and taxonomists on this new species. There are political reasons for creating a new name rather than referring to the existing name in the dissertation, especially if the new name reflects the area where the species occurs. So our preference is not to use the existing name. But it is clear that we need to justify that in reference to the existing name, either by saying that we consider it taxonomically invalid and that, following discussions with the dissertation author, we have decided to create a new name. Or, if the new taxon is morphologically distinct from the 70,000 year old one, we could justify a new name on the basis of that.

The problem at the moment is that we do not actually have specimens of the new species. Its distinctness is based on genetic studies which show clearly on a range of markers that the present taxonomy cannot be correct. We do have one skull of the species but it died in a zoo of some awful bone disease (Buchem's disease) and the malformed skull cannot be used as a type specimen. We do have photos and hair samples, and maybe the species could initially be described on the basis of those until further material becomes available. So, there is obviously work to be done.

I initially asked the question to make sure that we are doing the right thing because the last thing we need is bad publicity because of "unethical" behaviour. But I think with all the information above, I know enough to make the right decisions. Many thanks again.

Sam, thank you for your answers and your additional infos to the code, same to Robert. Ethics are important and I am also working on several species that were accidentially or not accidentally re-described under new names by several authors and I try in my next publication to set that right and to give back the credits to the original autors who are not alive anymore but who nontheless deserve it. The code is a collection of rules which are kind of agreed on and not a law (you cannot be dragged to court because of them) and I think that they by themselves are ethics and that it is good that they develop with time due to discussions like this to make things even fairer. I learned a lot from this discussion even if it was not my question and thank therefore also Erik for his question.

I think that, the best way is just to inform the real author to make the publication properly to make species valid. I don't think that anybody must try to use someones already done work. This is the shame. There are a lot of things to do and search. In case that you are unable to find the author of dissertation or similar works, or you have complete information about things going on, or you have agreement, then of course you can do whatever you decide to do and explain it in the paper. About validity of species colleagues are giving good answers.

Dissertation does not make the name authentic for many reasons. If you are in possession of the type specimen, you ca submit it at some museum and come in contact with some authority in your field who can authenticate the name and description of the new species, then you can publish it. That should be ok.

I am facing the same issue with my dissertation on Liberian butterflies. When I got to this dilemma, I did not even one to find out more, but I've chosen to describe all new taxa in various scientific papers. This way, I can achieve a double goal. I'll have peer-reviewed publications in my subject to support my PhD and I do not need to worry about this dilemma anymore :)

Cheers,

Safi

The code is quite clear as has been mentioned some time ago. It is also clear that it depends on the country in which you produce your thesis. The message is that it is always better to be on the safe side and publish in an appropriate journal as well as in a thesis..

I second Peter's summary point above. Be on the safe side and save future investigators a lot of difficult digging and searching and publish in an appropriate journal.

Erick, you wrote "He admits himself that his thesis is not readily available, and that his name may be a nomen nudum. " In my opinion the name is neither a valid name, nor a nomen nudum simply because it is not available at all. I think a nomen nudum is the name of a taxon published without proper description, but otherwise introduced in respect of the other criteria of ICZN art. 8.1.1.

I think all of these issues are well canvassed in a recent issue of Zootaxa ( Zootaxa 3735 (1): 001–094; http://dx.doi.org/10.11646/zootaxa.3735.1.1; Dubois et al.) In this is clearly indicates that except where a thesis was published, it will be invalid from the point of view of nomenclature for a variety of reasons - fundamentally it will not meet the requirement of simultaneous copies etc. Later, ie the next day week, etc, copies or pdfs distributed come under the description of 'facsimiles' of original unavailable publications and so are themselves not available. The exception is if there was a substabtial change to the document and that the new published date could then be considered as a distinct publication - but if so any contained nomen would take the date of that new publication.

Secondly it is irrelevant how many times a name (genus + species) is actually used in an invalid or unavailable way - for each time the nomen consists of the genus + species plus author + date, and so is a distinct nomen. Thus the same genus plus species with a new author and date is clearly a different nomen to be assessed independently for its validity in terms of the code. Thus, in the simple case of an unavailable use in a thesis - the same author or another can reuse that name in an available and valid way at any future date. The obvious problems that theses generate is that others then know the taxon is there waiting to be named and might provide a valid nomen for it before the original person gets around to it. This happens. Basically I would advise to not ever place apparently new nomina in theses - they are not necessary and convey nothing.

Definitely not valid

The issue with theses is, as a number of people have observed, not always clear cut. If the thesis is validly published, then there shouldn't be a problem. However, this also raises an other issue:

If a thesis is validly published, can a species described in it later be published as a new species in a journal? I would think not, as it has already been published!

It is also sometimes the case that names of new taxa are published in abstracts of conference proceedings prior to them being validly published (i.e. in a journal with description etc). Having them named in a conference proceeding renders the names nomen nudem and unavailable in future, so when the taxa are later properly published, a new name will have to be assigned.

If you have new unpublished taxa you want to discuss in a conference, it is best to call them sp. 1, 2, etc to avoid future problems.

I agree with all that John says , except the point about availability of nomina nuda. A nomen may be a nomen nudum at one publishing but such a 'genus plus species plus author plus date' is a distinct nomen than if in part is duplictaed in future, eg same genus and species and author but at a different date - will then be a different nomen! If the new binomial meets the criteria of availability it will become the valid name of the taxon. There are numerous examples where this has happened, e.g the combination Apteryx rowi was published at least twice as nomina nuda before it was published by authors in a valid and available way and so the name became valid. The important point is that a species nomen has 4 parts - genus - species-author-date and if any one of these varies it is a different nomen.

In addition to the requirements for publication, names introduced after 2000 require that the author explicitly indicates that they are introducing a new species name, rather than using a manuscript / thesis name for a taxon, and they must fix a name bearing type for that species. I don't think any of this is common in a thesis.

It is likely the name is not valid, but in order to know, one needs more information. First, which year was it published? Before 1987, 1987 to 1999, 2001 to 2012 or after 2012 all have different criteria for being published! After checking that, one needs to check if the name is available. You have to provide more information. From 1987 on you did not need a printed product, only identical copies and from 2001 on multiple identical copies were not needed anymore, just five digital copies placed in suitable institutions. It become even less restrictive with a centralized depository from 2013 on - hopefully. There are several exceptions to these as well as other requirements affecting availabilty after publishing is acceptable.

Dear Jyrki:

I would like to obtain the citation of the articles and codes that you pointed out in each cases, it would be easier to learn more. Thank you in advance. Eugenia

If someone has described a new species in a thesis, or argued for a change in nomenclature for an already described species, then they really ought to be persuaded (by their supervisor?) to publish their findings in a journal.  This question about publication in a thesis is arising far too often and, clearly from the answers, there are conflicting views.  My suggestion would be to write officially to 'The International Commission on Zoological Nomenclature' and obtain a ruling - this may well be different for different countries and the Commission should be asked to state which countries have appropriate thesis publication procedures. 

Do the species described based on single specimen are considered valid and as follow up there is no further description. The type specimen is lost and not available for any comparison.   Can someone help to highlight, in such situation will this species is considered valid?

In answer to Kuldeep, A species may be described on a single specimen and it often happens. So long as the name is made available in a  nomenclaturally valid way (see code) but needs stmt of intent to name species, a type specimen in a public repository, and a diagnosis that is validly (in terms nomenclature) published. The adequacy of the diagnosis is not relevant! If the type then becomes lost, that is unfortunate, but is an often occurrence. it does not invalidate the nomen!. A person revising the taxon has to assess the taxon as described and if they cannot separate it from another senior name by the data at hand they can synonymise it. If they cant separate it from several taxa they can make it a nomen dubium - the nomen however, remains a valid and available name though from teh point of nomenclature. If the taxon can be identified with other specimens but there is a new one potentially in the same genus then there is a case to make a neotype to stabilise the taxonomy - and this is often done, but ONLY if the original type is lost with no realistic hope of refinding it

Without a specific case one can look at, it may be difficult to know for sure if a description is valid or not. One has to check whether it is published ( a special term not meaning publishing as usually), available and includes the right information (at least). IF one wants to be sure his/her new species is not described in a specific context, that is today easy. Juts include a disclaimer - code 8.2. I suggest everyone include that in his/her thesis. In many European countries the thesis includes more or less the same version of an article that may be published later. The disclaimer takes the problem away and the valid descripion is then the published one in the journal.

As to Kuldeep Lal's question, I want to add that it depends on the date. Singletons are ok, but the code requires certain things after certain dates (several different ones) and they should be checked, i.e. is there a  type specimen listed, is there a diagnosis, was it described conditionally etc. .

The question dates back some time now and we have been able to compare the Late Pleistocene teeth with the new taxon. The measurements of the dentition of the new taxon fall outside those from the fossil material so it seems pretty clear that we can give the extant species a new name, as indeed the new taxon is also different from other extant taxa based on measurements on a range of morphological and ecological variables.

As so many times pointed out by others, taxonomic decisions are subjective and outside formal rulings. Your insight now given seems sound and fine, so congratulations and all the best! Lauri