Symphysodon tarzoo : discus-sion sur cette nouvelle espèce : Poissons tropicaux

Genetic relationships and variation in meristic counts, body shape and colour were examined in a large sample of Symphysodon collected from several locations in floodplain habitats along the length of the Amazon River. Surprisingly, mitochondrial DNA indicates no difference between the two historically described species, Symphysodon discus and Symphysodon aequifasciatus, but shows that non-clinal variation exists with a distinct lineage found in the western Amazon. This lineage is consistent with a colour form that is distinct from other Symphysodon lineages. This form has a parapatric distribution and is recognized as a distinct species, Symphysodon tarzoo. Adaptation to floodwater habitats supports genetic cohesion across a large range preventing fine scale regional diversification of the genus. Possible explanations for the unusual set of distributions for genetic and colour characters relate to the history of the Amazon basin and the probable division of lowland species when submerged geologic arches influence surface topology.

wistiti57 a écrit:
Et bien vive Symphysodon haraldi alors. Est-ce qu'on pourrait avoir des photos?

Matt's review gives the impression that there would be some difficulties in reconciling the results of Bleher et al and those of Ready et al., which could cause confusion in the hobby. Bleher et al. also gives much space to difference of opinion/result where there is practically none. The following may clarify why there is actually no reason to worry.

It was very flattering that Bleher et al spend two full pages objecting to Ready et al., but of course the former is mainly a popular paper and not one you are likely to read in the normal scientific press. Heiko has spent a fortune and considerable engagement in mapping the distribution of Symphysodon and his book, Bleher's discus (2006) is a valuable record of the aquarium fish business in South American over the last Century. Recommended reading.

I would like to stress that the molecular results of Ready et al and Bleher et al. point in the same direction. The same species are distinguished, with the same diagnostics, and there is absolutely nothing dramatically different about the analysis. We also both agree, that additional genes and more localities will further deepen the understanding of the group.

The only thing that is different are the names selected. Ready et al. refer to the green discus as S. tarzoo, and Bleher et al. call it S. aequifasciatus. The blue and brown discus (i.e., the most well known ones) are S. aequifasciatus in Ready et al., and S. haraldi in Bleher et al. Exit S. a. axelrodi.

Bleher et al. claim that Géry and Bleher in a publication in 2004 selected a lectotype for S. aequifasciatus that comes from Tefé (=green discus). We are unable to verify the existence of such publication, but if it exists, then the names should be reconsidered accordingly.

Ready et al. 2006 selected a lectotype from Santarém (=brown discus). There were several reasons for doing so. Among them, a wish to preserve aequifasciatus with the best known brown/blue form, and the problems (explained by Heiko) of authenticity of origin with material studied by Schultz.

In conclusion: There is no conflict, everything is still the way it was, but if the 2004 publication by Géry and Bleher can be produced, names may shift.

I also tried to trace the Bleher & Gery publication from 2004.

According to the literature cited in the description it shall have been published in Bleher's Discus vol. 1 on pp. 135-136. But this book was published in December 2006. In the quotation of the source "2004" there is no hint of any other source, even not to the book (except to the pages where it really was) itself, but to Bleher's publishing company (where it to my knowledge never was published before in the book).

As Axel Meyer, one of the contributors who prepared the data base (which is out of any doubt of being not carefully down, just the interpretation), told me, the publication could have done 3-4 years ago as the data were ready. But Heiko Bleher was too slow.

There are other mistakes. I traced the date of the original Lyons publication and it was indeed published in 1959, not 1960 (December 1959).

Bleher cites the code to try to show that the Lyons description was invalid. However, he tries to use the rules for recent descriptions for that before 1961. Under these rules - which are still valid for older descriptions - the description is valid as Sven Kullander pointed out long before.

Additionally, the data prepared by Meyer and colleagues may be misinterpret by Bleher. Meyer and colleagues just prepared them and A. Meyer told me that Heiko Bleher may have gone "a little bit too far" in his interpretations around haraldi.

I agree with Sven Kullander: Before Heiko Bleher can't prove that the lectotype was designated by Bleher & Gery already in 2004, all will remain as in Ready et al.

Dear all, and dear Sven,

I only can comment today, as I was collecting in the Pamirs until yesterday and I can see that there are a few points which have been overlooked in the above comments and I also want to contribue and clarify some points:

Firstly, I want to thank Sven for given some good comments on the scientific papers and also on my book.

Secondly, I must admit that in the our revision under Reference there were parts of the References missing, which have been corrected under ERRATA and will appear in aqua 13(1).

Thirdly, the revision represents the latest (newest) understanding/knowledge of the genus Symphysodon and is valid until further (additional) discoveries have been made. This is common in science, as science can NEVER give the final answer to all and every question, species classification, etc. But it is the most recent knowledge on the taxonomy (of the family/genus/species etc.). This is the way it was and will always be in science.

With other words: this classification (Bleher et al. 2007) is the latest accepted publication in the scientific community (therefore several reviewers worked/corrected and suggested its changes to lead to this finbal paper). It is the newest/latest understanding of the genus Symphysodon and its species.

Fourthly, to whom it might be of interest and also for Sven's information: the publication Géry & Bleher was only published in the German edition of Blehers Discus Band 1, in 2005 and delivered. (Although it is written in the front page of the book: 2006). In the Internet some dates are given as 9.05.2006, as to the general public it was shown at the INTERZOO 2006 in Nuernberg. In any case all these dates proceed the paper of Ready et al.

Besides: since Harald Schultz's definition of the green discus and his detailed description in 1958 (Schultz, 1959 – proceeding Lyons popular article), it was accepted and followed by L. P. Schultz's in his 1960 review of the genus Symphysodon aequifasciatus, the green discus, the red spotted green from Tefé (which Ready et al. in December of 2006 named tarzoo without an official description as a new species, nor having seen Géry & Bleher 2004 - published as above mentioned in 2005, but with the correct date 2004). The name S. aequifasciatus has been connected since Schultz (1958) to the green discus and NEVER to the brown or blue discus, and much less to the fantasy – unofficial – name tarzoo.
I have also written and classified it as such since my early publications in the 1970s and 1980s, as well as many other authors worldwide in tenth of languages.

I hope this clarifies some of the comments made here. And before I go: thank you also Rupert Collins for your nice comments.

anemone-clown a écrit:
Je n'ai toujours pas fini la future nouvelle fiche aquaBDD sur Symphysodon haraldi

La vidéo jointe à cette actualité est une pure merveille!!!