.... 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."
Posted by: Sven Kullander
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