Heiko's formalization of new discus genus revision

[devonpond]

Recently published, citation below. This work has no practical bearing on the hobby, but the link below summarizes what's new in discus taxonomy. Note that it's premature to guess whether scientists will actually adopt this proposed change.

Popular writing summary (http://www.practicalfishkeeping.co.uk/pfk/pages/item.php?news=1330)

Bleher, Stölting, Salzburger and Meyer (2007): Revision of the genus Symphysodon Heckel, 1840 (Teleostei: Perciformes: Cichlidae) based on molecular and morphological characters. Aqua 12(4): 133-174.

[billeagan]

interesting

[pcsb23]

I read this earlier today, it is intersting and a very good article.

One question though, if the experst can't agree on what starin a discus is what chance us? ;)

[brewmaster15]

One question though, if the experst can't agree on what starin a discus is what chance us? LOl Paul...and that is a very very valid question my friend!:)

At the end of the day..I am afraid I still look at the groups as I always did... as heckels, browns, blues, and greens and still see lots of Beautiful Discus...


A Rose is still a Rose by any other name

I would love for a definitive classification but taxonomy is seldom that cut and dry and always subject to revision as we learn more... Both of those groups research has contributed to that knowledge base...and hopefully additional ones will undertake the task and either confirm or refute data.... Its frustrating when we would like to know" now what may take years to know accurately....

Science builds on knowledge...checks and double checks....refutes and supports what is known...Thats what makes science such a strong tool in understanding the world.:)


Hopefully ...in my lifetime we will understand Discus species :)...then again... it does make for some interesting discussions.:)

-al

[Harriett]

I don't keep wilds [yet] and have no biz posting on this beyond my general interest, but I am throwing out one thing to look at. I read the linked article. I am a nurse researcher. The sample sizes that these results are based on, 48 specimens from 20 locations, would have zero credibility in a medical study. Just too small a sample to be useful to any statistician worth their salt. Feedback?
Harriett

[Polar_Bear]

My thoughts on this is that both Bleher and Kulander are using far too few specimens in their research, which is precisely how we got here in the first place. S. discus was originally named using ONE FISH!!!! To me, they are both continuing down this faulty path.

[Apistomaster]

Kullander has written as much that the sample size of his study was too small. Bleher has more up his sleeves that what he disclosed in this recent info. He is acutely aware of the problems all along that too few samples have been used by the various authors of revisions of the genus Syphysodon. I think it will later be shown that what he just published were only preliminary results.
I believe he has a vast amount of material from well documented collection locations that will be used in the next "last word." Much of this material is being subjected to additional work on the molecular genetic level which is a time consuming process given the large samples and normal meristic counts will be included in the study. Meristics have not proven to be of much use classifying discus species so far and likely will remain the same.

What I see so far is that he is only trying to establish priority on his preferred three species concept and that the proper names should in his opinion be; Green= aequifasciata not tarzoo, Blue/Brown are one and the same species which he prefers to name haraldi and there is little controversy over S. discus except those who think there is a subspecies S.discus willischwartzi which Kullander has already placed in synonymy with S. discus prior to Bleher who takes no exception with this.

It has been more useful so far to use water types and geographic locales to assign a discus to a species. Greens and Heckels are always found in black water and separated by thousands of kilometers from each other. The fish found in white clear water have been blue/brown variants and appear to make up the largest group and are the most variable in appearance. They are distinctly better adapted to a wider range of water chemistry and are far easier to breed in captivity.