Lasiancistrus planiceps invalid?

[Marc van Arc]

New species

Lasiancistrus planiceps

is regarded as a synonym of Lasiancistrus caucanus in both FB and CoF.

[Shane]

Armbruster says,

L. planiceps (Meek and Hildebrand 1913) (synonym of L. guacharote), but then I can't find where he explains why in his paper.

http://www.auburn.edu/academic/science_ ... asian.html

Fishwise states,

* Valid as Lasiancistrus planiceps (Meek & Hildebrand 1913).

Isbrücker 1980 - [ref. 2303] - Classification and catalogue of the mailed Loricariidae (Pisces, Siluriformes). Page: 46

Burgess 1989 - [ref. 12860] - An atlas of freshwater and marine catfishes. A preliminary survey of the Siluriformes. T.F.H. Publications, Neptune City, New Jersey, U.S.A. Page: 434

Isbrücker 2001 - [ref. 25653] - Nomenklator der Gattungen und Arten der Harnischwelse, Familie Loricariidae Rafinesque, 1815 (Teleostei, Ostariophysi). Page: 25, 29

Isbrücker 2002 - [ref. 27178] - Nomenclator of the 108 genera with 692 species of the mailed catfishes, family Loricariidae Rafinesque, 1815 (Teleostei, Ostariophysi). Page: 20


* Synonym of Lasiancistrus caucanus Eigenmann 1912.

Armbruster 2005 - [ref. 28554] - The loricariid catfish genus *Lasiancistrus* (Siluriformes) with description of two new species. Page: 553

CLOFFSCA lists it as valid. Page 388.


This looks like one nobody agrees on....

-Shane

[Silurus]

But if Armbruster (2005) has examined the types of L. planiceps and conclude that they are conspecific with L. caucanus, we should follow this decision unless someone else proves otherwise.

[Jools]

That may be quite a big if. Even bigger a leap if you look at the drainages involved. Anyone point me in the direction of where the discussion around examination of the types is?

One wonders, if like Guyancistrus, this move was partially made without examination of the types?

Jools

[Suckermouth]

In the "Materials Examined" section of L. caucanus in Armbruster 2005, he lists the holotype and seven paratypes of L. planiceps.

[Jools]

Sorry, was going on the online version which doesn't have materials examined. It also appears to have several errors. One is key to this discussion. Maybe it got fixed in the printed paper, that is, above the genus key, there is a range map.

In that map, what is the species depicted with squares Milton?

Thanks,

Jools

[Suckermouth]

Ah, I see. You're right, it does appear to have at least some errors. The squares are L. caucanus, and not caquetae as said on the Lasiancistrus page of Jon's website. Furthermore, the map in the publication further notes that the black square closest to the top left corner of the white box is the type locality of L. planiceps, which makes it not too far away from the type locality of L. caucanus, at least relatively speaking.

[MatsP]

Anyone want to say "Let's go with..."?

--
Mats

[Shane]

If L. planiceps (which was described from Panama) is a jr synonym of L. caucanus (Rio Cauca, Colombia Magdalena drainage) then we have a single species with a trans-Andean distribution. This seems illogical.

the black square closest to the top left corner of the white box is the type locality of L. planiceps, which makes it not too far away from the type locality of L. caucanus, at least relatively speaking.

The actual distance, as the crow flys, is not that far. The real issue is that between the two drainages lie two colossal geographic boundaries. The Cordillera Oriental, and arm of the Colombian Andes that averages over 8,500 ft (2,600 meters) in elevation and the Darien, the famous "missing link" of the Pan-American highway.

I have not collected this sp in Panama, nor have I ever seen the types, so I can't make any comparisons based on actual observations. I can only point out that, from a distributional point of view, it is illogical that they would be the same spp.

We can go with Jon's findings, but I am confident that L. planiceps will eventually be "resurrected" once more material is collected and studied.
-Shane

[Jools]

I'm inclined to keep it separate, however it will need to be done so with data in the clog to back up that view.

So, just to thrash this out, how do we know it's not pre-Andean?

Jools

[Shane]

how do we know it's not pre-Andean?

I do think Lasiancistrus, as a loricariid lineage, is pre-Andean as it is found in all the drainages currently separated by the Andes. Only a very few loricariid genera share that claim: Sturisoma, Hemiloricaria, Ancistrus, and Hemiancistrus, come to mind. I have always thought of these genera as the "building blocks" of the family. Leptoancistrus and Fonchiiichthys are found in the Cauca/Magdalena basin and up north in Panama as well, but no where else.
-Shane

[Jools]

Hi Shane,

So, if it's pre-Andean, then the facts it's relatively old and across drainages separated by the Andes may lend weight to Armbruster's view. What do you think?

Jools

[Shane]

I think it adds weight to the generic placement which makes Lasiancistrus one of (if not THE) most widely distributed lineages of the family.
That two populations seperated since the rise of the Andes in the Cretaceous (between 145 and 65 million years ago) are still the same species? That is another question altogether...
Note what the distribution looks like when one can see the terrain.
-Shane

[Suckermouth]

Apparently Armbruster found little evidence to split L. planiceps from L. caucanus. I agree with Silurus here. I do not think that L. planiceps and L. caucanus, if they can be distinguished, will be differentiated without fresh specimens from across the range. On the other hand, this may be an instance of "cryptic species" in which morphologically similar or identical species are distinct evolutionary lineages. The general lack of documented cryptic species phenomena in loricariids is owed to relative lack of molecular work in the group.