Chaetostoma L444 = Chaetostoma tachiraense

[MatsP]

According to L-welse.com,

L444

is Chaetostoma tachiraense, and it comes from Rio Tachira (again, according to L-welse.com)

However, there is a Rio Tachira in the Rio Meta drainage as well as in the Maracaibo basin.

Can anyone shed some further light on this? Did Schultz give any details as to which Rio Tachira the fish was caught in?

--
Mats

[Jools]

collected by Leonard P. Schultz in the Rio Tachira 7km. north of San Antonio, Estado de Tachira, Venezuela, on April 1, 1942. The Rio Tachira is a tributary of the Rio Zulia, Catatumbu system, Maracaibo Basin.

There's a good bit of text on similar species but the easy difference is this species has an "almost forked" caudal fin. I'd like to understand the reasoning of putting this name to number - doesn't make sense to me.

Jools

[MatsP]

So, I believe this is a case of "two rivers with the same name, not at all connected". So, L444 is found in the Rio Meta/Rio Tachira, but C. tachiraense is from the Maracaibo/Rio Zuila river called Rio Tachira.

L-Welse is wrong, from what I can tell.

--
Mats

[Jools]

Resolved? Might be worth a wee clog update suggesting for L444 that, "Some sources have identified this L-number as C. tachiraense, however this would seem to be down to confusion of between the Orinoco Basin, Rio Meta tributary Rio Tachira where aquarium fishes are collected and the Maracaibo Basin, Rio Zuila river called Rio Tachira from which C. tachiraense was collected and described.".

Please tidy up my scribbled note. Just dashing out the door!!!!


Jools

[MatsP]

Comment added to species entry, and moved to resolved.

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Mats

[Acanthicus]

Hi Jools,

I'd like to understand the reasoning of putting this name to number - doesn't make sense to me.

I´ll try to explain what made me do so:
The colouration is identical, as well as the pattern. But thats not as important as a morphological characteristic: Schultz (1944) wrote, that Chaetostoma tachiraense can be distinguished from all other Chaetostoma by having a small skin fold at the backside of the supraoccipital bone. That made Chaetostoma tachiraense unique until we got to know L 444. But L 444 does have this skin fold too.

Concerning the distribution: Chaetostoma tachiraense is described from the Río Tachira and Chaetostoma sp. "L 444" from the Río Meta basin. You are totally right that Chaetoostoma species dont have such a huge distribution area normally, but Werner (1993) caught some like Chaetostoma tachiraense looking fish in the Río Meta basin too.

I will have to take a look at the paper again, concerning the caudal fin.


best regards

[MatsP]

The problem with descriptions like "The only species that has <insert something 'unique'>" is that when a new species/variant/form is found that has the same feature, this sort of statement stops being valid. For example,

Ancistrus dolichopterus

is the only described species with more than 8 rays in the dorsal fin. But I know that L071 has 9 rays in the dorsal fin. So a statement of > 8 rays is unique in a scientific paper would mean that L071 is also A. dolichopterus, which I think we agree is not the case. Just that the scientific keys haven't taken that into account yet.

Do you have a picture of a live C. tachraense (the real one from Maracaibo drainage, not the Rio Meta ones...)

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Mats

[Acanthicus]

I know exactly what you mean and I share your opinion. A new species should be described in fact of more characteristics than just one. But if some morphological and visual features agree with another species or variant the possibility of analogy is given. Only this characteristic wouldn´t make me say L 444 is C. tachiraense. As I said before, I will look at the paper of L 444 again.

I don´t have a picture of the "real one", you won´t even find it in the "Wels Atlas 2". But do you have a picture of L 71 having 9 dorsal rays? I only know L 71 with 7 or 8.

[MatsP]

I think we may mean different things when saying 7, 8 and 9. I mean I,8 = 9, where I think (from another post) you count only the soft rays, so come up with 8.

To my count, the above is I,8 = 9 rays.

Most Ancistrus have 8 rays in total.

Unfortunately, my German reading ability is stretched when reading a McDonalds menu, never mind trying to read long, scientific text, so I can't (without lots of effort) make out what the L-welse page you link to says, but I think we agree - just using different ways of counting.

--
Mats

[Acanthicus]

Hi,

ok, we agree, like you said. I only count the soft rays.
I just posted the link because of the pictures there of the dorasl fin. You don´t have to read, don´t worry.

regards

[Shane]

L 444 does not match the photo I have of C. tachiraensis that appears on page 83 of Peces del Catatumbo Galvis et al 1997.
Peces del Catatumbo shows an overall gray bodied fish with light colored, tiny spots on the head and rostrum. The upper and lower sections of the caudal (it is slightly forked) are whitish yellow. The photo also has the "quilla carnosa en el extremo del supraoccipital" circled in the photo to draw attention to this feature.
They describe distribution as Rio Catatumbo system, Lake Maracaibo Basin between altitude of 1,000-2,000 meters above sea level.

-Shane

[MatsP]

Thanks Shane, I've added the quite from the book (with reference) to the datasheet for C. tachiraense - I think Jools have a few other data subs to complete first, but eventually it should get through...

--
Mats

[Shane]

L 444, I was unfamiliar with this number, is from Colombia. They are common in Chaetostoma shipments that originate in Villavicencio. Note they are not actually collected there, per se, but rather somewhere nearby on the Andean piedmont.
I thought we had this fish under a different name? Why change it to L 444?
-Shane

[MatsP]

L 444, I was unfamiliar with this number, is from Colombia. They are common in Chaetostoma shipments that originate in Villavicencio. Note they are not actually collected there, per se, but rather somewhere nearby on the Andean piedmont.
I thought we had this fish under a different name? Why change it to L 444?
-Shane

I think it was Jools that decided to change it's name - I think it was called C. aff_milesi, or some such, which, according to Jools was "not very aff. milesi at all, and better to call it by its L-number". I may have it wrong - in fact, it may have been called sp(1) or sp(2). It changed some 2-3 months ago, I think.

--
Mats

[Jools]

Why change it to L 444?

Originally it was in as C. cf. thomsoni. That was debunked and it's been C. sp(2) for several years. Now it has an L-number, I renamed it to that. It would be confusing to have it as sp(2) and the L-number as a common name.

On the ID front, calling it C. tachiraense based on the skin fold logic seems slapdash to me. C cf. tachiraense at a push but Chaetosoma are much more speciose group than many think IMHO - I'd bet no ones looked at all imported species for the skin fold. It'd be good to get a photo showing this as I am not familiar with the feature.

Jools

[MatsP]

Just because I like that sort of thing:
Fishbase lists 45 described species.
We have 26 species in the Cat-eLog, and about half of those are described.
So, we have about 25-30% of the total number of species in the Cat-eLog.

However, if we believe in what for example Shane says, there are several dozen more speceis, at the very least.

--
Mats

[Jools]

Mats,

The point is that they're more separated, many are not river fish. Shane and I have collected them in water that doesn't pass your ankles. Piedmont populations are effectively cut off from other piedmont populations by the warmer rivers that these populations would need to traverse to get "down the mountain and back up". And that doesn't even take into account waterfalls and other things.

Also, if look into the geological history, this distribution doesn't make sense either. Common ancestor, yes, but not now (in my opinion).

Jools

[MatsP]

I think I follow that. More isolated population -> more/faster speciation (because they don't back-cross with their slightly different ancestors).

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Mats

[Jools]

I edited my post, it was poorly written. So, just more, not faster. More especially if we assume their common ancestor pre-dates the Andes and was widespread.

Jools

[MatsP]

Yes, I agree. What I meant by faster is that, in a more isolated, smaller population, changes have more chance of "sticking" than if the "changed" form crosses back with the unchanged form, if you see what I mean.

--
Mats

[Shane]

More especially if we assume their common ancestor pre-dates the Andes and was widespread.

Jools is right on all counts. I believe Chaetostoma will be the most speciose genus of loricariidae when all is said and done. Not only does every piedmont stream have its own species, it usually has 2-4 Chaetostoma species. I strongly suspect, for various reasons, that there was once a widespread proto-Chaetostoma/Ancistrus as I am not aware of any drainage system that has one of these genera but not the other. There were other spin offs of this ancestral (Ancistrinae) fish (Lasiancistrus, Cordylancistrus, etc) but none were so successful as Chaetostoma.
-Shane