Symphysodon comprises five species

[cichla]

Symphysodon comprises five evolutionary significant units

Amado, Farias & Hrbek (2011): Genetic characterization of Amazonian discus fishes of the genus Symphysodon based on microsatellite markers: implications for systematics and classification. Intern. J. Evol. Biol. In press.
Abstract
Historical interest in the Neotropical cichlids of the genus Symphysodon has generated a number of studies and taxonomic revisions in both the professional and hobbyist literature. While these efforts have resulted in the recognition of phenotypically differentiated varieties and in the description of several species, they have at times generated unnecessary taxonomic uncertainty and produced contradictory classification schemes. In an attempt to contribute to the systematic knowledge of this group of fishes, and to resolve some of the the current classification controversies, we analyzed 336 individuals from 24 localities throughout the entire distributional range of the genus Symphysodon. We analyzed variation at 13 nuclear microsatellite markers, and subjected the data to Bayesian analysis of genetic structure. The results indicate that Symphysodon is composed of four genetic groups: group PURPLE – phenotype Heckel and abacaxi; group GREEN – phenotype green; group RED – phenotype blue and brown; and group PINK – populations of Xingu and Cameta. Although the phenotypes blue and brown are predominantly biological group RED, they also have substantial contributions from other biological groups, and the patterns of admixture of the two phenotypes are different. The two phenotypes are also characterized by distinct and divergent mtDNA haplotype groups. All phenotypic groups also show differing levels of mean habitat use. We therefore conclude that Symphysodon comprises five evolutionary significant units: Symphysodon discus (Heckel and abacaxi phenotypes), S. aequifasciatus (brown phenotype), S. tarzoo (green phenotype), Symphysodon sp. 1 (blue phenotype) and Symphysodon sp. 2 (Xingu group).

[Philippe Burnel]

Hi Ingo, it possible to get a pdf file ?

Philippe

[Philippe Burnel]

http://www.sage-hindawi.com/journals/ijeb/aip/360654/



Thanks Ingo

[Rico Morgenstern]

The entries for several nominal Symphysodon species in Catalog of Fishes have been updated:

http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatget.asp?spid=16602

http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatget.asp?spid=70097

It seems that Gery & Bleher actually failed to fullfill the requirements for a valid lectotype designation for S. aequifasciatus (as has been discussed fully by Willem in several publications); and therefore the designation of the Santarém specimen by Ready & al. (2006) is valid. Furthermore, Symphysodon Discus Tarzoo Lyons, 1959 is an available name, a conclusion with which I concur. That means, if the "three species solution" is followed, the nomenclature proposed by Ready & al. (2006) would be the valid one. If more species are recognized, as indicated in the paper of Amado & al., S. haraldi could be used for the 'Blue Discus' as an additional species, provided the considerations of Bleher & al. (2007) regarding the type locality are correct

[cichla]

Thank you Rico for the post. Step by step we are closer to obtain a 'robust' nomenclature and taxonomy of the discus – species.
Well two things are fixed now: (a) the species-group taxon tarzoo Lyons, 1959 is available and (b)the lectotype designation by Gery & Bleher is not valid. However, another challenge arise: the true type locality of S. haraldi? This is however only of interest in the ''five species solution'' introduced by Amado et al. (2011).
When I understand the ''five species solution'' by Amado et al. (2011) correct, then this ''species model'' has the disadvantage that some (in particular the S. spec. 'Xingu') proposed species (called evolutionary significant units in Amado et al.) are not distinguishable by morphological characters. The recognition of such units as species is not possible under the Code of Zoological Nomenclature. The naming of allopatric populations differentiated only by minor, neutral molecular genetic character as species is under discussion. And it seems to turn out that the majority of taxonomists and ecologists refuse to recognize such units as species. If there are indeed no morphological differences between the five ''evolutionary significant units'' it is unlikely that the Xingu-form will appear with a formal species name.
Greetings, IS

[Willem Heijns]

I must congratulate Bill Eschmeyer for having achieved such authority. When he speaks, everyone listens and moreover, believes what he says. I happen to be more sceptical.

It appears Eschmeyer has accepted the work of Amadi et al (2011). One element of that work is the recognition of the name Symphysodon tarzoo as valid. This simply is not right. The ICZN is very clear on this:

Art. 5.1 (partly): "The generic name must begin with an upper-case letter and the specific name with a lower-case letter [Art 28]."

Art 28 (partly): "a species group name (is always to begin with) a lower-case initial letter, regardless of how (it was) originally published."

Art. 11.4 (partly): "The author must have consistently applied the Principle of Binominal Nomenclature [Art. 5.1]"

Now one might argue that it is allowed to have species-group names start with an upper-case letter if that name refers to a person. But this was abandoned in 1931. Names published before 1931 must now also be written with a lower-case letter, hence the provision in art. 28.
On top of that, the name tarzoo cannot even be treated as such. The provisions for "personal names" were created for people (i.e. the endings -i and -orum for men and -ae and -arum for women). Tarzoo doesn't qualify here because it is not a (personal) name but an acronym of the name of an institution (Tarpon Zoo in Florida).

No room for discussion here, I'd say.

[cichla]

Dear Willem,
yes, this is a good point. And I should mention that I don't like taxon names which are just became available by the carelessness of authors.
Any species name in zoology needs to satisfy the Articles 11–20 of the Code to be available. Thus, - in my point of view - the only relevant article (of these mentioned by you) for the decision whether tarzoo is available or not is only Art. 11.4.
Since, I don't read Lyons' paper by myself, I have to trust Hrbek and Kullander who did. Both wrote that Lyons used the principles of the Linnaean nomenclature. At least Kullander (a member of the International Commission on Zoological Nomenclature) treated tarzoo as available (Kullander 1996).
So, I cannot accept your dictatorially ''No room for discussion'' here
Yours, IS

[Willem Heijns]

Article 11.4 has a specific reference to article 5, simply because article 5 states the Principle of Binominal Nomenclature. I agree article 28 is of less importance here.

I did read Lyons's paper of 1959. The spelling of his new subspecies is "Symphysodon Discus Tarzoo". All upper-case letters here. And not allowed. I wonder which articles/provisions in the Code could be used to turn this around.

In his treatment of Lyons' paper Kullander does not mention the upper-case letter problem. Instead he goes through a lot of reasoning to conclude that others who rejected the name tarzoo because of a lack of description are wrong. And they are. There is a description, conditional or not. See also my first article on the matter.

And then, being a member of the Commission doesn't make one infallable, does it?

[Rico Morgenstern]

I must congratulate Bill Eschmeyer for having achieved such authority. When he speaks, everyone listens and moreover, believes what he says.

Noone has such an authority, except perhaps the writers of the Holy Scriptures (and even to them this applies only with regard to the religious). Just to avoid misunderstandings: The update in Catalog of Fishes was a welcome occasion to revive this discussion. I do consider CoF as a highly valuable source of information, and I have the greatest respect for Bill's work. Nevertheless I am well aware (as is Bill, I guess) that it is not infallible. Otherwise such updates would be hardly necessary, wouldn't they?

It is right that species group names must not begin with upper-case letters. This is stated twice in the code, in Art. 5.1 (5.2 with regard to subspecies, respectively; in each case with reference to Art. 28) and in Art. 28. There is no effective date stated in this context, e.g. something like "names published after 1931..." etc. (I know it was allowed under the former "Régles..." to use capital letters for personal names but there is no reference to this in the current code), so this applies to all names published after the the starting point of zoological nomenclature. Thus, following your reasoning, Paraneetroplus Bulleri, Cichlosoma Robertsoni, Petenia kraussii, Heros Helleri, Acara Maronii (which is not even named after a person), and many, many more names would be unavailable.

However, you have overlooked that the code states exactly how to deal with names which are spelled in this way:

32.5. Spellings that must be corrected (incorrect original spellings).

32.5.2.5. In a species-group name first published with an initial upper-case letter the initial letter must be replaced with a lower-case letter; in a genus-group or family-group name, or name of a taxon above the family group, first published with a lower-case initial letter the initial letter must be replaced with an upper-case letter.

I would admit that the inclusion of the regulations about initial letters in Art. 5 is somewhat misleading with regard to application of Art. 11.4, this will hopefully be remedied in the upcoming 5th edition (see: http://iczn.ansp.org/, this page is unfortunately not always recallable). However, the inclusion of such cases in Article 32.5 leaves no doubt that species-group names first published with an initial upper-case letter are available. They are simply treated as incorrect original spellings and thus available in the corrected form.

And then, being a member of the Commission doesn't make one infallable, does it?

Let's hope so

[Willem Heijns]

You know I don't give up easily, don't you Rico.

Let us assume that it was once allowed to use upper-case letters in species group names (we seem to agree there). I still believe 1931 was the year that was abandoned. In my reasoning that would make species group names published before 1931 with an upper-case letter available. So, still following my reasoning, the names bulleri (Regan 1905), robertsoni (Regan 1905), kraussii (Kaup 1878) helleri (Günther 1864) and maronii (Steindachner 1882) are all available. Tarzoo (Schultz 1960) is not.

Still you hit an interesting point. If articles 11.4 and 5.1 render species group names starting with an upper-case letter unavailable, then why have an article like 32.5.2.5 where species group names with an initial upper-case letter are treated as incorrect spellings? No need to specify provisions for unavailable names is there? Unless of course this last article is about those names once made available under older versions of the Code.

My suggestion to the ICZN would be to make this distinction clear. If not, the Code is inconsistent and there would be no need to have the Principle of Binominal Nomenclature state anything about upper- and lower-case letters.


BTW: What a lovely way to spend a Sunday afternoon! Listening to good music (old Celtic songs by Loreena McKennitt), finishing my Australoheros article and having this discussion.

[Rico Morgenstern]

Let us assume that it was once allowed to use upper-case letters in species group names (we seem to agree there). I still believe 1931 was the year that was abandoned. In my reasoning that would make species group names published before 1931 with an upper-case letter available.

I can only repeat that there is no such ruling in the current code. With regard to the former editions and their precursors, Art. 86.3 applies.

86.3. Force of previous Rules and Codes. The rules governing zoological nomenclature contained in former editions of the International Rules of Zoological Nomenclature and of the International Code of Zoological Nomenclature, and any amendments affecting the Code, have no force unless reaffirmed in this edition, and then only as herein expressed.

Thus, the code does not allow a distinction between names published before 1931 and after 1930 in this case. In my view, it is superfluous to have the regulations about initial letters fixed in Art. 5.1 and 5.2. However, in both cases, there is a clear cross reference to Art. 28:

Article 28. Initial letters. A family-group or genus-group name or the name of a taxon above the family group is always to begin with an upper-case initial letter, and a species-group name always with a lower-case initial letter, regardless of how they were originally published.

BTW: What a lovely way to spend a Sunday afternoon! Listening to good music (old Celtic songs by Loreena McKennitt), finishing my Australoheros article and having this discussion.

I like Loreena too

[cichla]

Dear Willem, dear all,
Whether an author is using the 'Binominal Nomenclature' or not depends on how he treat the species epithet. That means, when an author used the species epithet as a name and not as part of the description (as usually done before Linnæus and still by some in the 18th century) then the name is available (if it satisfy art 10-20). It has nothing to do whether the epithet is beginning with an upper-case letter or with an lower-case letter.
I am not an advocate for or against the availability of the species-group taxon tarzoo. Fact is, however, that Kullander (1996), Amado et al. (2011) and Eschmeyer (2011) gave reasonable explanation why tarzoo is valid.
Greetings, IS

[cichla]

Dear all, beside the discussion about the validity of the taxon tarzoo, I think it would be worth to discuss how many species should be recognized.
(a) one species, means S. discus only, (b) two species = S. discus and S. aequifasciata, (c) three species as in Ready et al. 2006, or (d) five species, how it is treated by Amado et al. 2011.
What do you think?

[Rico Morgenstern]

Ingo, you brought up an interesting point.
Recognizing only a single species would be by no means absurd when the phenotypic variation is compared with that of some other cichlids (e. g. Aequidens tetramerus or Heros efasciatus), and there are many lowland species in the Amazon which are that (or even much more) widely distributed; and it would have the great advantage of making all the debates on the validity of lectotype designations and availability of tarzoo superflous.

The 'two species solution' as accepted prior to the publicationss by Ready & al. and Bleher & al. must certainly be abandoned. The differentiation between S. discus and S. aequifasciatus did rest in fact on a single character, namely the pronounced middle vertical bar vs. vertical bars of equal intensity. Some other color characters noted by Kullander (1996) are not useful because of the intraspecific variability in what was then called S. aequifasciatus. The meristics evaluated by him vary in both, and show a considerable overlap. So if this character is regarded sufficient to distinguish species, one would have to recognize the third species, S. tarzoo, on the basis of the characteristic reddish spots. One may even argue, that this color trait is of greater significance than the pronounced middle bar, as the latter is only an accentuated element present in all species, whereas the red spots are apparently unique. From this point of view one could take another "two species solution" into consideration, which is even to some extent supported by the molecular studies of Ready & al.: Symphysodon discus (with aequifasciatus, haraldi, axelrodi and willischwarzi as synonyms) and S. tarzoo. In the light of this possibility, the selection of the Santarém specimen as lectotype for S. aequifasciatus would indeed be an unlucky choice.

All this is of course speculative, and in any case each of these views would be difficult to accompolish as, unfortunately, Discus taxonomy is to a large extent also a 'political issue'.

[Willem Heijns]

I am not so much into the one, two, three four of five Symphysodon species. Sorry guys. Interestingly though in Rico's new "two species model" one of the species would have to be called Symphysodon tarzoo. Which again brings us to the issue "is tarzoo an available name?"

A couple of days ago I argued: tarzoo is not available because it is in violation with articles 11.4 and 5.1 of the ICZN. Both articles (or their equivalents) were in force when Lyons (1959) proposed his new name. My question is: do you agree with this view and, if not, which articles of the Code do you think reject my view?

More or less apart from this fundamental issue is the fact that the Code is inconsistent in quite a few articles. But let's put that aside for a while.

What do you say?

[cichla]

I would say: A proposed new name becomes available (in the sense of zoological nomenclature) if it fulfill the rules of the Chapter 4 ''Criteria of availability'' of the Code (means articles 10-20 of the ICZN). Article 11.4. require that an ''author must have consistently applied the Principle of Binominal'' only. Before 1961 the rules were not so strict. In 1961a revised edition of the code appeared. Art. 11(c) of these rules (I am using the German edition of the code): The author of an article must have consistently applied the Principle of Binominal Nomenclature(II) consequently. Under point II: The scientific name of a species is a combination of two words (binomen) and that of a subspecies is a combination of three words (trinomen). In all cases the first name is the genus name, the second the species name and the third (if used) the subspecies name. As you may see there is no lower-case letter nor upper-case letter mentioned. And the rules for 1959 were even less strict.

Nevertheless, whether tarzoo is valid or not depends on how the disclaimer given by Lyons is treated and whether Lyons used consistently the Principle of Binominal Nomenclature or not. However, I am convinced, that the availability of the taxon tarzoo has nothing to do if it is written with a upper-case letter.

[cichla]

Upper-case letter:

Let us assume that it was once allowed to use upper-case letters in species group names (we seem to agree there). I still believe 1931 was the year that was abandoned. In my reasoning that would make species group names published before 1931 with an upper-case letter available.

I can only repeat that there is no such ruling in the current code. With regard to the former editions and their precursors, Art. 86.3 applies.

I can only add that there was no such rule before 1984 (see my post above).

How many species: Regarding the results by Ready et al. (2006) the two species option would be most appropriate. How Rico explained it means Symphysodon discus and S. tarzoo (if the taxon name tarzoo is available). There are also some authors who argued that it would be best to recognize only S. discus, because there are intermediate specimens (nowadays such specimens are just treated as hybrids). The recognition of five species (as suggested by Amado et al.) is only possible – in my point of view – if there are also phenotypical differences between the ''evolutionary significant units'' and not only neutral genetic differences.

Forgotten names: How I mentioned above I dont like taxon names which are based just on the negligence or the carelessness of authors in aquaristic journals. I can repeat a 'friend' of mine who like to say: ''there are species seekers who travel to remote regions to discover new species. And there are 'name seekers' who are searching in old aquaristic journals for forgotten names. They dig out such names, because otherwise nobody would know that they are working on this fish group as taxonomist.'' I don't know if my friend is right or not (I think his thoughts are satirical), but there are some who are 'name seekers'.
Cheers, IS

[Rico Morgenstern]

That all species group names have to begin with a lower-case letter (including names derived from names of persons or places) was already fixed in the so-called 'Strickland code' (1843) which was the first attempt to regulate the Zoological Nomenclature. It was later moderated by permitting initial upper-case letters for species-group names formd of personal names under the editions of the "Régles Internationales de la Nomenclature Zoologique" in force between 1905 and 1930, in the 1931 edition this permission was removed, as correctly pointed out by Willem. However, nowhere in these precursors of the Code it was stated, that a wrongly used initial letter would render a name unavailable. In the first two editions of the "International Code of Zoological Nomenclature" (1961, 1964) it was fixed in article 28, and was simply to be corrected under Article 32 (c). In the third edition (1985), the provisions of the use of upper- and lower-case letters, sespectively, were (for whatever reason) included in both Article 5(a),(b) and Article 28. The wording of Article 28 was the same as quoted in my last post (from the fourth edition), and after Article 32(c)(i) a spelling which "...contravenes a provition Articles 27 to 31" was an incorrect original spelling, simply to be corrected under Art. 32 (d).

I am not aware that, in the systematic groups I deal with, a name has ever been rejected as unavailable for the wrong use of initial letters under these provisions, when they where in force. But do not forget, they ain't in force anymore: not for names published after 1999, not for names published before 2000 but evaluated now. Only the provisions of the fourth edition (1999) are to be followed, and they still dictate that a name spelt in this way is to be treated as an incorrect orgininal spelling, it is available in its corrected form.

32.4. Status of incorrect original spellings. An original spelling is an "incorrect original spelling" if it must be corrected as required in Article 32.5. An incorrect original spelling has no separate availability and cannot enter into homonymy or be used as a substitute name.

Insofar as the second part of this article is concerned, there is not even an inconsistency with Art. 11.4.

Nevertheless, whether tarzoo is valid or not depends on how the disclaimer given by Lyons is treated

What says the code:

8.2. Publication may be disclaimed. A work that contains a statement to the effect that it is not issued for public and permanent scientific record, or for purposes of zoological nomenclature, is not published within the meaning of the Code.

8.3. Names and acts may be disclaimed. If a work contains a statement to the effect that all or any of the names or nomenclatural acts in it are disclaimed for nomenclatural purposes, the disclaimed names or acts are not available.[...]

In my view, the simple statement by Lyons of the name being inofficial does not fulfill the requirements to be disclaimed, even less if the context of this statement is taken into consideration, namely the statement that it "...undoubtedly will be recognized scientifically when the proper authorities have completely examined them". "Inofficial" means thus simply "tentative" but does not exclude the name from zoological nomenclature (note that the term 'official' is nowhere used in the code in the sense of 'available'). The name may be regarded as conditionally proposed, but as it was established before 1961, this does not render it unavailable (Art. 11.5.1).

Forgotten names: How I mentioned above I dont like taxon names which are based just on the negligence or the carelessness of authors in aquaristic journals. I can repeat a 'friend' of mine who like to say: ''there are species seekers who travel to remote regions to discover new species. And there are 'name seekers' who are searching in old aquaristic journals for forgotten names. They dig out such names, because otherwise nobody would know that they are working on this fish group as taxonomist.'' I don't know if my friend is right or not (I think his thoughts are satirical), but there are some who are 'name seekers'.

I agree in this point, Ingo, and the problem of carelessness about using names is not restricted to the aquarium literature. However, whether we like it or not, such names - when published before 2000 - are often available. And in this case, the name was not 'dug out' somewhere but was taken into consideration immedially after its publication by Schultz (1960). Fortunately, at least inadvertent establishment of new names is now prevented by Art. 16.1.

[cichla]

Rico, thank you for the informative and reasonable contribution . So, I think it is clarified that tarzoo is available. Anyhow, I think it wouldnt be necessary to 'dug out' the name. Since Schultz (1960) treated it as unavailable, it would have been possible (in a kind of silent agreement) to let it rest in peace. However, since it was reanimate, we have to face all the problems with the availability of the taxon name. Well, I have to admit that the case of tarzoo is not a classic case for a ''forgotten name''.

[Rico Morgenstern]

Since Schultz (1960) treated it as unavailable, it would have been possible (in a kind of silent agreement) to let it rest in peace. However, since it was reanimate, we have to face all the problems with the availability of the taxon name.

This is indeed true, at least there was the possibility to select another lectotype for S. aequifasciatus, in which case S. discus tarzoo would have become a junior synoynym. However, Ready & al. deceided differently and established facts which are now to be accepted.

The recognition of five species (as suggested by Amado et al.) is only possible – in my point of view – if there are also phenotypical differences between the ''evolutionary significant units'' and not only neutral genetic differences.

I agree here. Without clear-cut morphological and/or color differences, it is rather useless to recognize such units as species.