Why is L200 both Hemiancistrus subviridis and Baryancistrus demantoides?

[eeeeemo]

I'm confused...

Why is L200 both Hemiancistrus subviridis, http://www.planetcatfish.com/cotm/co...article_id=151 and Baryancistrus demantoides, http://www.planetcatfish.com/catelog...pecies_id=1805?

How do differentiate them?

[soltari007]

H. subviridis is the one that looks similar to L128, stocky body and no high fin.

B. demantoides is the one that looks skinnier, and has a high fin.

[Quixotic]

Before we go into the story of L200. here is an introduction to the L-numbers.

See Wikipedia, L-number, http://en.wikipedia.org/wiki/L-number (as of Jan. 4, 2008, 17:13 GMT).

The L-number system is a semi-scientific classification system of catfish based on photographs of shipments of tropical catfish of the family Loricariidae published by the aquarium magazine DATZ (Die Aquarien und Terrarienzeitschrift).

An L-number is not an official scientific name, but it does allow people to identify various Loricariid catfish by a "common name" before the fish is actually officially described. When a Loricariid receives an official scientific name, the L-number is retired. [1]

In general a specific L-number classification does not guarantee a discrete species—multiple L numbers have been given to different populations of the same species. To add to the confusion, sometimes a single L-number may actually be used for multiple species.

Additionally the aquarium magazine 'Das Aquarium' introduced a similar system using the prefix 'LDA'.

L200 was originally assigned to an olive greenish-yellow fish with off-white to yellow spots caught from the Río Orinoco drainage. This fish has not yet been described at the time, so there is no scientific name for this fish.

Interestingly, L200 appears in both regular and shark-fin/hi-fin forms. The dorsal fin seems to be the apparent distinguishable feature for all similar looking olive greenish-yellow fish caught along the Rio Orinoco drainage. To make matters worse, there is an inky black fish with off-white to bluish spots that looks similar to L200 which is again found from the Rio Orinoco drainage, although the colour is different. This is L128.

It is possible then that both the regular and shark-fin/hi-fin L200 forms may be the same species, showing sexual dimorphism where the shark-fin/hi-fin form is thought to be a feature of the male. Together with L128, there are suggestions that all three forms may just be just population variations or showing some form of sexual dimorphism of the same species, or perhaps, different species altogether.

This was not until the scientists took at look at L200 and studied them. It was found that the different forms for L200 are actually different species, where the one without shark-fin/hi-fin is Hemiancistrus subviridis and the one with shark-fin/hi-fin is Baryancistrus demantoides. So they aren't showing sexual dimorphism after all and L200 ends up being shared by two different species.

For those interested, the scientific paper can be found here.
Werneke, David C.; Sabaj, Mark H.; Lujan, Nathan K.; Armbruster, Jonathan W. (2005). "Baryancistrus demantoides and Hemiancistrus subviridis, two new uniquely colored species of catfishes from Venezuela (Siluriformes: Loricariidae)" (PDF). Neotropical Ichthyology 3 (4): 533-542. Sociedade Brasileira de Ictiologia.

As the scientists have not looked at L128 yet, it is still not known if L128 is the same species as L200.

[Heiko Bleher]

Hi all of you L-freaks,

my name is Heiko Bleher and I wanted to wish you all a very healthy and (fish)happy new year.

I just saw the thread of L-numbers and wanted to tell you: I collected and classified loricariids (=L-cats) long before the L-system started, which happened while some German sat over beer... Today it is so incredible confusing, specially as 3 )or 4) different L-numbers exist (every publisher uses his own and one of the three, or four is the worst of all).

Loricariids (family Loricariidae with about 800 different species now classified, including many so called L-numbers) are a very diversified group, but almost all species, if described or not, can be classified by several morphological characters and also by their teeth (very important). With the later it is almost all the time possible to place them into their genera they belong to, and than they can be added ie: Baryancistrus sp. 1; sp 2, etc., although the type location should (in science must) be added. This leads to a clear classification and understanding, not the L-numbers.

I do not want to mention here now all the errors in the L-numbers (several species in the orginal L-numbers, are completey wrong genus and many are, as the above, several species involved and others have been given two numbers (one I know of hand even 3 different numbers) and they belong to only one species with color pattern variation.

So do not worry, it is a big problem and do not even try to get into it. Enjoy the fish you have, tread them well and make them happy with a correct biotope. I have already found more than 800 different once of these so called L-numbers, but as you see only 400 have been "classified" by so called experts (none is a scientist), and as said wrongly, or very wrong.

Keep up the good work and enjoy the fishes,

always

Heiko Bleher

[soltari007]

I can only imagine that the L numbers are great(and confusing) for hobbyists, and terrible for scientists, with the double and triple overlapping classifications. The number of royals that are grouped under one number L27 is amazing. Not to mention if the plecos cross-breed as well...

Happy New Year to you too Heiko

Grüße,
Sam

[Gecko]

For all it's flaws, the L-number is still a great system for traders and hobbists until the scientists catch up in describing all the species. But I do believe once the sp. is described, its L number should be retired.