Separation or convergence

[dan518]

With the possibility of Kronoheros being separated and maybe more amphilophus species being described, does anyone else think there going to far?
To my knowledge there is no set markers for differentiating species.
So would people prefer more species or more convergence like what happened with synspilum and melanura. Maybe do the same with zonatus and coatzacoalcos, some of the amphilophus citrinellus group and quite a few other examples I could list, then just use catch location to describe.

 

[duanes]

It all depends on the DNA evidence, the melanura synpillum convergence was not due to a whim, but because the DNA suggested they are the same.
Coatzooalcos and zonatus DNA may suggest they are not so close.
Just because some fish look similar does not mean their evolutionary ties are close enough to merge them.
I believe the more DNA research progresses, names may or may not change.
Whether an aquarist likes it or not, is irrelevant.

 

[dan518]

It all depends on the DNA evidence, the melanura synpillum convergence was not due to a whim, but because the DNA suggested they are the same.
Coatzooalcos and zonatus DNA may suggest they are not so close.
Just because some fish look similar does not mean their evolutionary ties are close enough to merge them.
I believe the more DNA research progresses, names may or may not change.

But from my limited understanding there is no standardisation in the dna results it still comes down to how someone interprets the results.

 

[BC in SK]

But from my limited understanding there is no standardisation in the dna results it still comes down to how someone interprets the results.

Sure.
It is always going to be somewhat arbitrary where they draw the lines between some species. Never going to be black and white.
We leave it up to the experts, the ichthyologists, to decide where to draw the lines because it is really beyond our capabilities. Some are splitters and some are lumpers so there is not always a consensus. The modern seems to be much more splitters then the past. And the notion of sub-species has lost favour as it is not really used anymore.
Only mitochondrial DNA is used to determine the ancestral relationship of cichlids. There has been a few attempts to use nuclear DNA but the researchers basically conclude that CA cichlids are too closely related to shed any light. Just about all of these CA cichlids use to be in one large genus ( Cichlasoma) and all are gentically close enough to hybridize. So there trying to determine the relationship between the very closely related. Even one hybirdization event millions of years ago, and the mitochondrial DNA could show a relationship today that is not really accurate.

 

[duanes]

If you are a lumper, you could essentially conclude that all Vieja are simply 1 species.
V bifasciatum, melanurum, hartwegii, breidhori maybe even fenestraus. They all have similar body shape, red heads, and can all hybridize ( it seems all Heroine cichlids can).
In older times, dentition was a major factor in splitting. But because separation into species from a single ancestor due eo environmental changes, can easily, and quickly change detention, favor individuals that use whats available. If a soft food source becomes unavailable because of a volcanic eruption, etc (even a simple rock slide altering a stream) denition adapts often in only a few generations.
Even in a tiny place like Cuatro Cienigas, if snails over populate, the jaws and teeth of certain H minckleyi make the snail eaters the dominant sub-species until they eat most of the snails.
Yet so far, all 3 types of minckleyi, are considered minckleyi.
But in a lumper generalist view, minckleyi, carpintintus, cyanoguttatus, maybe even deppii might be considered simply one species. They all have iridescent spots, similar body shape and easily spawn with each other, etc. As we (humans) advance in technology (that is, if todays politics allow), I believe DNA will become less and less abstract (if you can call splitting the genome abstract).
Remember not that long ago, the human consensus was that world was flat, and disease caused by evil spirits.
I'm sorry to say, I believe the tendency of some human populations to want to resurrect those old notions, because as far as we can see with the naked eye.......or because we can't see bacteria with the need eye, they must not exist.......

 

[dan518]

Yes I understand all of this, heroine cichlids all share one common ancestry, and now we have the ability to separate by dna not all differences will be visible to the eye. I read an article a while back which I have been trying to find again (no luck so far) saying that if heroine cichlids where held to the same standards of other animal groups we would have less species then we do now. From my understanding scientists still disagree how much divergence there needs to be to class a new species and thru different animal groups there is alot of difference.
What I really wanted to know was as hobbyist do people get excited when new species are described as a new fish to collect or fed up as another hard to distinguish pit fall enters the hobby.

 

[duanes]

Personally, I have been pleased with many of the new separations.
I did not think bocourti or pearsei belonged in Herichthys. And also thought the species now in Nosferatu did not belong in Herichthys.
One that I don't feel has gone far enough, are the uropthalmus.
If you compare the salt water uropthalmus near isla de Mujeres with the ones near Progresso, or even some in the cenotes of Riviera Maya, there are quite a few obvious visual differences, that to me give the appearances of different species of Mayaheros, but if the DNA says (like melanurus and synspillum) they are same, then I go with the scientific view.
If I was a lumper I might say freidrichsthallii and loisellii are the same species, because the only obvious differences is slight color variance, and located in different river systems.
Its a dammed if you do, dammed if you don't catch 22.

 

[BC in SK]

I read an article a while back which I have been trying to find again (no luck so far) saying that if heroine cichlids where held to the same standards of other animal groups we would have less species then we do now. From my understanding scientists still disagree how much divergence there needs to be to class a new species and thru different animal groups there is alot of difference.

Yes, the lines between species are drawn at different points through out the animal and plant kingdom. Species is a notion for our purposes and whether or not it's in our interest to have few or many names will have some bearing on where lines are drawn. Even amongst cichlids there seems to be different standards for where to draw lines between species. Our 150 or so CA cichlids could be 1500 species if they applied the same standards as they have with some other cichlids.
Long before this DNA study on melanura/synspilum, there was question as to whether they should be regarded as the same species because based on the original descriptions they could not be reliably distinguished. There choice wasn't 1 or 2 species, but 1 or many species (and then possibly some hybrid populations in between). It just makes more sense to view it as one highly variable species over a larger range.
Minckleyi was originally described as 3 species. It's only from the observation and knowledge that all 3 feeding morphs can come from the same spawn that they are now regarded as one species. Based on DNA, RD and midas cichlid in the great lakes of Nicaragua, are more closely related then midas cichlid from different lakes. So it is not the genetic distance that science is regarding them as separate species but rather the belief that these feeding morphs don't regularly crossbreed. And maybe they don't. My understanding is that there is a similar thing with lake trout in the great lakes though your not going to get lake trout split into numerous species because well.....it's lake trout and not a cichlid. If it was somehow determined that the feeding behaviour was learned behaviour from the mother (and they all have the exact same mitochondrial DNA as their mother) then that might invalidate the notion they don't crossbreed. But just spitballing

 

[duanes]

A friend of mine just described what he considers to be a separate species of Labeotropheus and has been getting flak from some of the lumpers, so again, its a bit of dammed if you do dammed if you don't.
Below is the title of his research.
Two New and Remarkably Similarly Colored Species of Labeotropheus (Perciformes:Cichlidae)fromLakeMalawˆi,Africa

Michael J. Pauers1,2,3