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In the cat-e-log there is a listing for Chaetostoma cf. thomsoni but not one for Chaetostoma thomsoni.
Could someone explain this? I know what cf. means, so I'm wondering how can you have a cf. without the original? Is there no holotype for C. thomsoni ?
Any help with this would be great.
Deborah

That's because the real C. thomsoni is most likely restricted to the Rio Magdalena drainage in Colombia and is most likely not the same species as the one seen in the trade.

I think I understand. Is the one seen in the trade, cf. thomsoni, collected from the Rio Tulumayo at the upper end of the Rio Ucayali river system? Is that why you say it's probably not the same species, because it's from an entirely different collection area?

Deborah

Yes, I think that's how it works - since the fish described is from ONE place, and some fish that looks very similar is from another area, until scientists have decided that it's got a bigger natural habitat, it's called cf. something.

--
Mats

Thanks, Mats. Do you think I've got the location area for cf. thomsoni right?
Deborah

In Mergus Wels Band 2, it appears to be listed as Chaetostoma tachiraense, but there aren't official "synonyms" listed. But, it seems there are 5 other names this species has. Each name has a year and a person attributed to it. So, who gets the official name, and which are the synonyms? Or, do people disagree with the name C.tachiraense?
Amanda

The Wel Atlas ID is incorrect, but all I can do is complicate the issue more...

According to the Chaetostoma key in "Los Peces Del Rio Magdalena" (Miles, 1947) C. thomsoni can be distinguished from the other Magdalena Chaetstoma by "aletas dorsal y caudal unicolor, o con pocas bandas anchas" (dorsal and caudal fins unicolor or with a few broad bands). Further on, Miles states "cuerpo y aletas unicolores o con poca pigmentacion, 5 o 6 espinas interopercules" (body and fins unicolor or with a little pigmentation, 5 or 6 interopurculum spines).
Ok, based on this description, identify a C. thomsoni!. It is impossible and even appears that Miles is likely making reference to what are probably several distinct spp.

C. tachiraensis, on the other hand, is well defined both by Schultz (1944) and Galvis et al (Peces del Rio Catatumbo, 1997). In fact, Galvis et al even have a nice photo of C. tachiraensis. It is not the "C. cf thomsoni" common to the hobby and pictured in the Welse Atlas.

The overall body color of C. tachiraensis is similar to the common "thomsoni" of the hobby, but the caudal is deeply concave, the dorsal has "5 or 6 dark spots om membranes between dorsal rays and not on dorsal rays," and "dark pigment evident near tips of middle rays forming an obscure dark band across the rear edge of caudal, except white tips of upper and lower lobes."

The other very distinguishing feature notable in the Galvis et al photo is that C. tachiraensis has a dark rostrum (snout) with light dots and not a light-colored rostrum with dark spots like our "thomsoni." The final "smoking gun" is that "thomsoni" shipments do not come to Bogota from Tachira. In fact Tachira shipments are quite rare. "Thomsoni" show up in Villavicencio shipments. That said, I do not know if they are collected there or simply picked up somewhere between Villavicencio and Bogota from collectors in the Magdalena basin during the trip to market in Bogota.

Bottom line: 1) The Welse Atlas ID is clearly incorrect and 2) We may never know if the "thomsoni" of the hobby is really that sp or not as the available descriptions of C. thomsoni are useless as identification refs. Someone needs to go back and check Reagan's original 1904 description and see if it includes any useful identifying characteristics.

-Shane

Are we having fun yet? No wonder I can't find a match for this poor guy!

Lately, there seem to be "mixed" shipments, from where I'm sitting. One of these, two of those. All listed as "Thomsoni" or just "rubberlipped." Internet and LFSs say they're coming in as mixed batches, but they call them "Thomsoni" or "rubberlipped" for "ease." Ease of what?
Amanda

That's a good-looking fish, Amanda. Lucky!
I'd love to stumble on a mixed shipment. Remember "contaminents?"

Yes, I'm having fun. I love learning all there is to know. Between this, and what Shane PM'd me, I have a good idea of how to describe the possible collection range of cf. thomsoni, albeit in a lengthy way, for a general article that I'm writing about this species.

And I can see what the LFS means by "ease." They are probably dealing with undescribed species, and don't know where the fish was collected any more than their usual customer does. It's enough to say "Chaetostoma sp." in most cases, for general care information.
At least, that's what I think.

Deborah

It's enough to say "Chaetostoma sp." in most cases, for general care information.
At least, that's what I think.

That is the bottom line. I have probably collected a dozen or more Chaetostoma spp. and they are all found in basically the same environmental conditions.
-Shane

According to the original description by Regan, the color is given as "Brownish; a small dark spot at the base of each dorsal ray; caudal with small dark spots on the rays."
This description refers to a preserved fish, but it is likely that C. thomsoni is a species without any distinct markings on the head and body (that would have been visible even in preserved material).
The figure accompanying the original description is given below:

Thanks a bunch for that HH! Still no positive ID resolution, but we may have ruled out C. thomsoni as an ID for the common Chaetostoma.
-Shane

There's a couple of things I can add in here.

Firstly, cf. and sp. cf. mean two different things in the cat-elog but are used incorrectly. How I ever got such a basic thing wrong and how no one noticed it until now I do not know. There is a post in the bugs forum about this and I do plan to fix it but it's a couple of weekends work.

Secondly, Hans and Ingo have more information about the Chaetostoma species from the Ucayali but I don't have it all straightened out yet.

Thirdly, you can treat Chaetostoma like Corydoras every second minor tributary has its own "species".

4. I should really publish the picture above shouldn't I? Anyone else think it doesn't look anything like a Chaetostoma?

Jools

Deb, I'll get it on the list. Contaminant is one that I keep forgetting. Thank you for the reminder and the compliment. He runs laps in the evening and skips on rocks I've set up on the bottom. It's quite nifty skipping. I'd like to get him in a tank larger than the 20 long(especially if I find more like him).
Amanda

Jools wrote:

I should really publish the picture above shouldn't I? Anyone else think it doesn't look anything like a Chaetostoma?

I don't think the sketch artist quite captured the rubberlip aspect of the Chaetostoma. This drawing gives the fish a slightly prehistoric look. I like it.

and:

Firstly, cf. and sp. cf. mean two different things in the cat-elog but are used incorrectly.

I had noticed this, but thought it was some scientific thing that I didn't get. Sometimes it's hard to decide what questions to ask. (Don't want to risk embarrassment.)

Amanda, I like the way they skip around the tank, too. One of my set-ups with cf. thomsoni (I'll call them that, for now) has white sand and you should see him go! There's always little white swirls settling down, like little white clouds, as he skips by.

Deborah

I should really publish the picture above shouldn't I? Anyone else think it doesn't look anything like a Chaetostoma?

Yes, the above pic should be on the site if possible.
Checking the latest Chaetostoma papers I have on hand, I do not see any mention that anyone has reviewed the C. thomsoni material (is it still around?).
I also agree about the pic above as well. Note the thickness of the caudal peduncle and, most importantly, the odontodes shown on the pectoral. Not excatly Chaetostoma characteristics. Are we looking at what should be Lasiancistrus thomsoni?
What name do we start using for the good old "Thomsoni" of the hobby?
-Shane

I don't think it looks like a Chaetostoma. But, anytime I see these types of illustrations, it doesn't quite look right to me. Maybe I'm missing something.

I wonder how the Chaetostoma we know of today came about from what was? It seems like such a confusing history. There were so many different species once known as "Chaetostoma."

The odontodes on the pectorals show up, but they're short and fine on the species in the photo. Deb, have you noticed anything on your Chaetostoma sp.?
Amanda

No, I must say that my Chaetostoma have pectorals with edges as smooth as glass. I would need a magnifying glass to see any short protuberences of any kind. Frankly, when Shane wrote:

I also agree about the pic above as well. Note the thickness of the caudal peduncle and, most importantly, the odontodes shown on the pectoral.

I was sure he meant the sketch provided by HH. In that drawing, you can see the odontodes if you look. On the fish in the photo provided by you, Amanda, I can't see any pectoral odontodes (just little cheek ones!) and the caudal peduncle is kind of obscured.

Look at this species of Lasiancistrus (4 photos):
http://www.planetcatfish.com/catelog/lo ... 1258_4.PHP
I think this is what Shane is getting at.
Deborah

That was just what I was getting at Deb. Sorry I was not more clear. Reagan's original sketch, as posted above by HH, looks to me more like a sp of Lasiancistrus than Chaetostoma.

We are still at a loss as to a possible ID for the "common thomsoni" of the hobby.
-Shane

Even though he isn't "Thomsoni", here's another photo of his fins(this is how he eats zucchini):


Which is better in warmer weather: an airstone or warmer water(75 F.) with the powerhead? I already have some bottled water in the freezer.
Amanda

Petsmart say's they grow 24" anyone care to elaborate on that?

Which is better in warmer weather: an airstone or warmer water(75 F.) with the powerhead?

The airstone. The majority of powerheads I have used actually add more heat through their motor than cooling through the current they produce. A cheap clip on fan blowing across the tank's surface helps a lot too.
-Shane

Waldo wrote:Petsmart say's they grow 24" anyone care to elaborate on that?

I pointed this out to my local PetSmart, Waldo. The new(emphasis on new) manager at my local Petsmart was nice enough to give me the run-down on how things work: Each Petsmart has a list of fish they can put in "requests" for(a brief list). They may or may not show up on a delivery day. One of these fish is the "Rubberlipped Pl*costomus." I've seen no fewer than 5 different species in that one tank, all labeled the same. Maybe one of these species will make it to 24". My other favorite in Petsmart is the "Spotted Corydora." This can range from C.trilineatus to C.copei to undescribed C-#s. They're all mixed together. I only hope they can hold onto this good manager. The labels are printed by corporate Petsmart. All Petsmarts are to look alike. Petsmart even dictates which fish go in which tank. That would be good, if it were the correct fish. Have you ever seen Angelfish with Chaetostoma sp.?

Thanks, Shane! Airstone it is. I have some of those clip on fans, too.
Amanda

I've seen no fewer than 5 different species in that one tank, all labeled the same. Maybe one of these species will make it to 24". My other favorite in Petsmart is the "Spotted Corydora." This can range from C.trilineatus to C.copei to undescribed C-#s. They're all mixed together.

Perhaps the sole saving grace of the mega pet chain stores is that they are good place to pick up bycatch and mismarked livestock.
-Shane

they are good place to pick up bycatch and mismarked livestock.

If shoddy husbandry doesn't kill them first.

With Chaetostoma thomsoni, were there other misnamed representatives such as Chaetostoma anomola sovichthys and Chaetostoma anomala anomala (I think that's how it interprets) as recently as 1997?
Amanda

Bearing the intriguing label of Chaetostoma thomasii, here is a sweet little guy I picked up yesterday. Yet another undescribed species of Chaetostoma, this fish is from the PetSmart chain in my area, and it is the first one I've seen offered that doesn't have the typical thomsoni look.

He is still in the bag.


The flash makes him look brown, but he is actually a real charcoal black with white dots, as seen below:


Does anyone think this is the same species as Amanda's, posted earlier in this thread? Who is working on describing all these species? Who is Thomson, and who might Thomas be? I'm joking. I suspect "thomasii" is a misspelling of "thomsoni."

Deborah

EDIT: to adjust photo link.

I was just in Petsmart today (shame on me!), and I think they had the same fish as deb's, although they were a paler grey colour. They were mixed in with the normal 'thomsoni' type (every time I am at petsmart, these two species are mixed together). Anyway, one of the things I noticed was that the largest one *did* have quite well developed pectoral odontodes. Perhaps I should have bought it so I could get pictures. I may go back for some, and another store in town has some really nice milesi. I have an indoor pond which stays the correct temperature and has a fair amount of current in it, they might like it in there

jeff

Deb,
Your fish is the same as Amanda's. It is C. sp 4 in the Cat-eLog.
As to who si working the genus, ACSI lists Armbruster, Ortega-Lara, and Salcedo.
-Shane

It had never occurred to me before reading this thread to approach the manager for a request for rubber noses. I assumed that they didn't have even that much latiitude in ordering fish. I love contaminants.
You guys should see the furor over what is a true P. altum let alone the remarks made by Heiko Bleher that Altums have never been bred in captivity. That's just one species of angel fish. Seems that all the holotypes are in horrible conditions. Not only that, meristically, there is no difference statistically between the three known species. And then there is a cline theory where gradations are found from the headwaters to the mouth of the Rio Negro.
We catfish lovers could have it worse but at least the L### sytem brings us a little order.
Larry