I've seen cardinal tetra imported from Columbia sometime listed as Paracheirodon cf. axelrodi - which begs the question are they a different species that simply look very similar ?
Are columbian cardinal tetra the same species as brazil cardinal tetra
- Thread starter anewbie
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I found the notes section interesting here…
I've never seen 'cf' listings for the Colombian population but not surprised that they exist. The short answer to your question as to whether they are a different species is, not considered so at present. But check back with me in 2 million years. The one dna analysis I read, a while ago, stated there was not significant enough genetic divergence to suggest two species.
The notes that @Magnum Man linked us to are good. Stan Weitzman's paper that united the three 'neons' in one genus, Paracheirodon, (they were at one point in 3 different genera!) noted the slight differences between the two cardinal populations and that was back in 1983. In all this time no ichthyologist has taken it any further despite a great incentive to do so--naming a 'new neon.' Look at the lengths to which Axelrod went to get one named after him!
I've kept both populations though never at the same time...knowingly. I never felt like I was dealing with two different species. That said, we're living at a time when the very definition of what a species is is being challenged and rethought.
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People of the killie persuasion, like me, are used to the lines between local forms and species becoming blurred. As DNA has become a tool (still rather recently in the big picture), we're discovering things the human eye can't see, but that are significant in drawing the lines between what is what.
I studied and study history, not biology, but see the naming of species as a hunt for the history of the animal and of its environment. That's what I like to find out more about. We have creatures evolving in a directionless, complex process. We see them. We note differences. Some taxonomists are lumpers, with a tendency to see many differences as unimportant. Others are splitters, inclined to see differences as crucial. It's exactly how we see the history of countries, of religions, of arts, of music - we see what exists, but how it got there and when it started is worth questioning.
We look at diversity and try to understand where the cut offs are, and nothing is set in stone. We're animals trying to understand animals, and as new info comes in, we have to be able to adjust. In the aquarium world it may not matter except to breeders, but if you're curious about natural history, the story of change is very interesting. If you buy and keep individual fish you like to be able to name things, but you can call them "Ted" or cardinal tetras if you want. Call me Gary - but with my family name, you could trace geneology and learn a bit of the story of why I'm what I am where I am. The scientific, species names gives an opening to the knowledge known so far.
So you see two or more slightly different forms of the cardinal tetra, from different environments. If you sell them, you want to relabel them. That makes sense - new things sell for more money. If you study them and present good, solid evidence they've become two different forms you analyze as different enough, then you may argue they are different species. If your evidence is grounded and convincing, people who read or hear it will be convinced. If new evidence comes in and is as good, well then, people have to adapt as they learn (but only if they care about that learning).
I haven't seen any such work on looking at cardinals, so for now, they're Paracheirodon axelrodi, one species in the family Acestrorhamphidae, the American characins, of the order Characiformes. If someone makes a compelling case for it being 2 or more species, then if we know more, it'll stand. It hasn't been done.
Yet. Maybe never. We roll with what we know now.
I studied and study history, not biology, but see the naming of species as a hunt for the history of the animal and of its environment. That's what I like to find out more about. We have creatures evolving in a directionless, complex process. We see them. We note differences. Some taxonomists are lumpers, with a tendency to see many differences as unimportant. Others are splitters, inclined to see differences as crucial. It's exactly how we see the history of countries, of religions, of arts, of music - we see what exists, but how it got there and when it started is worth questioning.
We look at diversity and try to understand where the cut offs are, and nothing is set in stone. We're animals trying to understand animals, and as new info comes in, we have to be able to adjust. In the aquarium world it may not matter except to breeders, but if you're curious about natural history, the story of change is very interesting. If you buy and keep individual fish you like to be able to name things, but you can call them "Ted" or cardinal tetras if you want. Call me Gary - but with my family name, you could trace geneology and learn a bit of the story of why I'm what I am where I am. The scientific, species names gives an opening to the knowledge known so far.
So you see two or more slightly different forms of the cardinal tetra, from different environments. If you sell them, you want to relabel them. That makes sense - new things sell for more money. If you study them and present good, solid evidence they've become two different forms you analyze as different enough, then you may argue they are different species. If your evidence is grounded and convincing, people who read or hear it will be convinced. If new evidence comes in and is as good, well then, people have to adapt as they learn (but only if they care about that learning).
I haven't seen any such work on looking at cardinals, so for now, they're Paracheirodon axelrodi, one species in the family Acestrorhamphidae, the American characins, of the order Characiformes. If someone makes a compelling case for it being 2 or more species, then if we know more, it'll stand. It hasn't been done.
Yet. Maybe never. We roll with what we know now.
In another thread some months ago we broached the larger subject being teased here--what is a species? I offered at that time that I liked the most recent revision of Symphysodon (Discus) that found there to be three species but contained among those three species are two 'evolutionarily significant units' (ESU), which appear to be on a distinct evolutionary path. I like this. It acknowledges that evolution is not static, that there are populations of Species X that appear to be on the path of evolving into something separate. This might be the case here with cardinals.
I wonder what happened to the purported 4th Paracheirodon 'disovered' by Heiko Bleher. That was 2006, a while ago. Knowing Heiko's legendary zeal, which was up there with the best of them, we should have had a P. bleheri by now.
I wonder what happened to the purported 4th Paracheirodon 'disovered' by Heiko Bleher. That was 2006, a while ago. Knowing Heiko's legendary zeal, which was up there with the best of them, we should have had a P. bleheri by now.
TwoTankAmin
Fish Maniac
@Innesfan
From seriouslyfish.com --> https://www.seriouslyfish.com/species/paracheirodon-axelrodi/
I am a fan of cardinals. At one time I had 65 of them in my inwall 75 gal. tank. It was amazing to watch them school. What truly surprised me was one day I spotted a sick one which was swimming upside down in the group. It actually stood so much that I spotted it very quickly.
Here is the thing about this. Geographical boundries are an artifice of humans. When I was getting involved with keeping Altums one of the things I learbed was a lot of them came from the Rio Atabapo river which borders Colombia and Venezuela. For many years collecting Altums from this river meant one was risking their life because you were likely to be shot by the Venezuelan side. When that changed, a lot more Altums came into this country.
(edited for typos)
From seriouslyfish.com --> https://www.seriouslyfish.com/species/paracheirodon-axelrodi/
I am a fan of cardinals. At one time I had 65 of them in my inwall 75 gal. tank. It was amazing to watch them school. What truly surprised me was one day I spotted a sick one which was swimming upside down in the group. It actually stood so much that I spotted it very quickly.
Here is the thing about this. Geographical boundries are an artifice of humans. When I was getting involved with keeping Altums one of the things I learbed was a lot of them came from the Rio Atabapo river which borders Colombia and Venezuela. For many years collecting Altums from this river meant one was risking their life because you were likely to be shot by the Venezuelan side. When that changed, a lot more Altums came into this country.
(edited for typos)
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Species exist and can be observed. How fine and sharp the lines are can be the question. I too like the idea of Evolutionarily Significant Units. That makes sense.
Life never stands still and all we're doing is taking snapshots (often of things we destroy after) with our short lives in a long story. Species description following Linneaus' internationally useful system is less than 300 years old, and that's a blink in time. We've barely gotten started on figuring these things out.
Add to that there are tens of thousands of people trying to sort this out, and we're bound to have disagreements, different approaches, and especially different definitions. The best thing here is we aren't certain - people with all the answers are dangerous. I prefer the questions.
Life never stands still and all we're doing is taking snapshots (often of things we destroy after) with our short lives in a long story. Species description following Linneaus' internationally useful system is less than 300 years old, and that's a blink in time. We've barely gotten started on figuring these things out.
Add to that there are tens of thousands of people trying to sort this out, and we're bound to have disagreements, different approaches, and especially different definitions. The best thing here is we aren't certain - people with all the answers are dangerous. I prefer the questions.
Regarding the above, well put, @GaryE , and I agree entirely.
And as for this interesting point you raised in your earlier post:
Similarly, in his 1975 revision of Nannostomus, which had been in taxonomic chaos for a century, he united the then-known 11 species that were spread out over three genera--Nannostomus, Nannobrycon and Poecilobrycon--into one genus Nannostomus. And it too has held thus far, some 51 years later.
Is that all about to change what with dna? The splitters could have a field day and get to name countless 'new' species, many from the above two genera alone. That said, there seems to be something holding them back from doing so. It is interesting that in these two genera alone, Paracheirodon and Nannostomus, Heiko's 4th Paracheirodon and the several 'new' super-red and super-expensive Nannostomus have all gone undescribed and nameless for some time now.
And as for this interesting point you raised in your earlier post:
The current taxonomy governing cardinals stems from Stan Weitzman's 1983 revision of the genus. Stan was a dyed-in-the-wool lumper. He took three clearly related species--the neon, cardinal and green neon-- that were incongruously placed in three different genera--Hyphessobrycon, Cheirodon and Paracheirodon-- and united them in one genus, Paracheirodon, which stands to this day, some 43 years later.
Similarly, in his 1975 revision of Nannostomus, which had been in taxonomic chaos for a century, he united the then-known 11 species that were spread out over three genera--Nannostomus, Nannobrycon and Poecilobrycon--into one genus Nannostomus. And it too has held thus far, some 51 years later.
Is that all about to change what with dna? The splitters could have a field day and get to name countless 'new' species, many from the above two genera alone. That said, there seems to be something holding them back from doing so. It is interesting that in these two genera alone, Paracheirodon and Nannostomus, Heiko's 4th Paracheirodon and the several 'new' super-red and super-expensive Nannostomus have all gone undescribed and nameless for some time now.
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The other side is I look at Anton Lamboj's revision of Pelvicachromis, the krib group - fish dear to my heart. He was ultra-meticulous, and proved that the hobby krib (P. pulcher) was a different species from P. kribensis. P. taeniatus which was a big geographically sprawling species was split. P kribensis had been properly described in the past, and took most of the diverse looking Cameroon fish once seen as taeniatus.
I found the Nigerian taeniatus very different to keep than Cameroon ones. That they were two species made sense to me. P drachenfelsi was a larger fish that didn't fit taeniatus, and hobbyists had questioned that for a long time. P kribensis is still a group of differently coloured but similar fish. P. taeniatus may be 3 different colour forms.
It fits experience, and geography. I hate the phrase 'common sense', but the logic of that work was... logical.
All these divergences make sense to anyone who has kept the fish, so wild splitters would have expected even more descriptions. There's a methodical process going on. A lot of it is to clean up an old pre cold war cold war - German, British, French and Belgian ichthyologists were all out to prove their nation's science was best. Hitler even gave bounties to researchers to describe more species than his rivals' people did. It's a mess to clean up.
People are people, and we mess up a lot. But we can correct bad directions and move along.
My favourite book on West African cichlids is an older one by Lamboj, summarizing what science knew at the time. His own work made much of his book's fish names wrong (once the work had been properly done). I like that. It's how we learn.
I found the Nigerian taeniatus very different to keep than Cameroon ones. That they were two species made sense to me. P drachenfelsi was a larger fish that didn't fit taeniatus, and hobbyists had questioned that for a long time. P kribensis is still a group of differently coloured but similar fish. P. taeniatus may be 3 different colour forms.
It fits experience, and geography. I hate the phrase 'common sense', but the logic of that work was... logical.
All these divergences make sense to anyone who has kept the fish, so wild splitters would have expected even more descriptions. There's a methodical process going on. A lot of it is to clean up an old pre cold war cold war - German, British, French and Belgian ichthyologists were all out to prove their nation's science was best. Hitler even gave bounties to researchers to describe more species than his rivals' people did. It's a mess to clean up.
People are people, and we mess up a lot. But we can correct bad directions and move along.
My favourite book on West African cichlids is an older one by Lamboj, summarizing what science knew at the time. His own work made much of his book's fish names wrong (once the work had been properly done). I like that. It's how we learn.
Lumpers and splitters. Yes indeed. Even when the entire human genome has been sequenced (this doesn’t happen with fish DNA analysis) there is no agreement on whether Neanderthals are a separate species or belong with us as h. sapien. The answer depends entirely on which scientist you ask and which definition of "species" you use. Historically, they were seen as a separate species, but modern DNA evidence has made the line much blurrier. Species is an artificial but useful construct. Even Klingons and humans were able to breed.
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