How to distinguish LDA007 (L114) from L273?

[Runtunt]

I purchased a 6" pleco from Liveaquaria.com, image above. It was given both L273 and LDA007 IDs in their description. My understanding is that LDA007 and L114 are the same. Which ID is correct?Thanks in advance!

[Jools]

This is

L114

and not

L273

.

Jools

[Runtunt]

Thanks! What are the distinguishing markers? My fish doesn't seem have the "metallic sheen" of an L273, but is that a reliable phenotype? Similarly, what is exactly a difference between P. leopardus and L114? Pictures suggest that L114 has more yellowish base color than P.leoprdus. Is that right? Are there other features that are more reliable than the quite variable colors?
Runtunt

[SLIMESLAYER10]

L273 often have bigger spots and very small spots on there head while L114 has smaller more uniform spots all over its body, fins and head (still slightly smaller on head). L114 also (normally) have more red on there fins.

[7Pete]

Your fish has small head pattern so it's LDA07. LDA07 isn't L114, LDA07 looks more like "real" L600.

[SLIMESLAYER10]

LDA07 and LDA007 are used for L114, L600 and LDA07... don't you love common names!

[Runtunt]

Confusing indeed. I have changed my species registry to L114, with the understanding that I can not be sure. Wonder why genetics are not being used for to aid species description? After specific genetic markers are established by DNA sequencing, a simple PCR reaction could be used to ID species and strains. Are there efforts to do this? I am new to plecos and the ambiguity of L catalog numbers.

[racoll]

Wonder why genetics are not being used for to aid species description?

It is, slowly, but it's not always as simple as you make out.

Where you'd think that DNA is most useful---i.e. in cases like the complexes of closely related species or lots of variation---turns out that DNA can pretty ambiguous too for the easy-to-sequence mitochondrial loci. Of course, sequencing a much larger sample of the genome is possible, but that costs $$$ that are generally not available for this kind of work.

Often, DNA is actually more useful in the opposite situation, by associating species/populations that have radically different morphologies.

It's also worth bearing in mind that this fish already has a scientific name:

Pseudacanthicus leopardus

. It's found in the Upper Essequibo river, Rio Branco, and Rio Demini and Rio Jatapu (probably many others too). All these areas are close to each other, and have been or are connected in some way. The variation you see in the L numbers reflects samples taken from a small number of geographically separate collecting points, and not considering intermediate locations. There's probably a good case that one species name is enough to accommodate the variation, but without examining examples from throughout the range it's hard to say.

I'm all for cataloguing biodiversity, but not every little tiny difference needs to have a name. We should be comfortable in knowing where it is useful to draw the line.

Breeding for the hobby is another story, but that's more a problem with the collection information being absent at the point of sale. If this were better available, it would be more straightforward to keep the different population phenotypes separate.

[Runtunt]

Thanks "racoll". Yes, having the geographical origin of P. leopardus specimens would be useful. I recall that full genome sequencing has been done on Lake Victoria cichlids, addressing similar issues, including genetics of color variations. So there is know-how how to do this in fish. This research is driven in the context of evolution, and sponsored by academic funding agencies. Perhaps the "pleco community" can recruit the academic type to do a similar project. You seem to know quite a bit about the habitats of P. leopardus.

The research papers I have seen on plecos seem to be more descriptive, traditional taxonomy, using morphological markers to separate/describe species. These morphological markers are more variable than DNA sequence, not that your average dealer or hobbyist can/or want to routinely sequence ornamental fish for sale. I just feel badly about accidentally creating hybrids of potentially threatened species, by putting similar looking fish together, making them useless for conservation. I would be willing to pay $ to tell whether my fish are of the same species or not.

[racoll]

I recall that full genome sequencing has been done on Lake Victoria cichlids, addressing similar issues, including genetics of color variations. So there is know-how how to do this in fish.

Oh sure, the methods and the expertise exist, but the problem is cash. Sequencing this quantity of data is expensive.

This research is driven in the context of evolution, and sponsored by academic funding agencies.

Yup. It's hard to get money for straight up taxonomy.

The research papers I have seen on plecos seem to be more descriptive, traditional taxonomy, using morphological markers to separate/describe species.

Yeah, there are only a small handful of examples now, but there will be more in future featuring DNA data. See a recent one here: https://doi.org/10.1371/journal.pone.0189789.

[Jools]

@Pseudasmart has done a load of work on this very topic. I don't know if LDA007 and L114 are the same species or not.

Jools

[Linus_Cello]

@Pseudasmart has done a load of work on this very topic. I don't know if LDA007 and L114 are the same species or not.

Jools

Depends if you’re a lumper or a splitter?

[racoll]

Jools wrote:
Thu Apr 12, 2018 7:28 pm
I don't know if LDA007 and L114 are the same species or not.

Jools

Depends if you’re a lumper or a splitter?

I think you'd have to be the splitiest splitter of all time try and separate those two. Both fish come from the same river, and look the same.