Lima versus elongatus ID thread

[thebiggerthebetter]

Thanks to ColeFishing's push, I thought I'd put this together.

IME and IMO, the vast majority of people (in the US) thinking they are buying a Sorubim lima are actually buying a Sorubim elongatus. It appears far from trivial to tell one from the other using their exterior. Meanwhile, the adult size is quite different, 1' for elongatus and 2' for lima.

I still don't know what my old 7 were (never had a chance to grow them beyond 1') and neither do I know what my current 5 are (both do best and are spectacular in groups, especially when young; I'd recommend at least 7-10):


Here are some links for those who want to dig deeper into the ID issues:

Lima on PCF: http://www.planetcatfish.com/catelog/species.php?species_id=98

Elongatus on PCF: http://www.planetcatfish.com/catelog/species.php?species_id=697

From this review paper: http://www.mapress.com/zootaxa/2007f/zt01422p029.pdf .....

..... it would appear that the position of the mandibular barbels with respect to the gular apex is the ONLY way remotely feasible for a hobbyist to ID a live fish - find this key/algorithm in the revision, page 8:

Key to species of the pimelodid genus Sorubim
1 Gill rakers 31–37 (Fig. 1B)............................................... .................................................. ........S. maniradii
- Gill rakers 13–23 (Fig.1A, 1C)............................................... .................................................. ................... 2
2 Pectoral fin-rays 8; gill rakers on first arch modally 21; tooth patches on vomer not connected (Littmann
et al. 2001b, fig. 3b); insertion point of inner mental barbels even with or posterior to gular apex; head and
body elongate, body ovate in cross-section; eye diameter into interorbital distance 2–3 times; gape width
into head length more than 3.6 times............................................. .............................................S. elongatus
- Pectoral fin-rays 9, rarely 8 or 10; gill rakers on first arch 18 or fewer; tooth patches on vomer fused (Littmann
et al. 2000, figs. 4a and 4c,); insertion point of inner mental barbels anterior to gular apex; head and
body stout, body moderately compressed laterally; eye diameter into interorbital distance 3 times or more;
gape width into head length approximately 3................................................. ............................................. 3
3 Caudal fin with rounded lobes, distal caudal rays on upper and lower lobes curved (Fig. 2A); distributed
east of the Andes Cordillera .................................................. .................................................. .................... 4
- Caudal fin deeply forked and elongate, distal caudal rays on upper and lower lobes nearly straight and
pointed (Fig. 2B); restricted to the Lake Maracaibo, Sinu and Magdalena River basins.......S. cuspicaudus
4 Premaxillary tooth patch greatly exposed, exposed tooth patch length about equal to width (Fig. 3C); head
triangular and spear-shaped (Fig. 3B)............................................... ............................... S. trigonocephalus
- Premaxillary tooth patch moderately exposed, exposed tooth patch length contained 1.5 to 2.5 times in
width (Fig. 4); head oblong, not triangular........................................ ................................................. S. lima

http://www.planetcatfish.com/forum/viewtopic.php?f=13&t=30938&hilit=+lima - that's one of my original 7 lima/elongatus in the OP. As you could see, our colleague Back (high level hobbyist) from Finland thinks the position of the mandibular barbels with respect to the gular and other skull features may be telling, based on this paper.

http://www.monsterfishkeepers.com/f...1-SPECIES!!!&highlight=elongatus+lima+article

http://www.monsterfishkeepers.com/f...as-valid&highlight=elongatus+lima+differences

http://www.monsterfishkeepers.com/f...-thread-and-updates/page3&highlight=elongatus - page 3 especially

Colleagues from Europe, e.g., Netherlands, report seeing 2' limas often, which appears to be in a stark contrast with my (US) experience. This one gotta be a lima - close to 2': http://www.monsterfishkeepers.com/f...-catfish&highlight=elongatus+lima+differences - such photos are quite rare for some reason and no big ones on YouTube (http://www.monsterfishkeepers.com/f...Great-big-huge-lima-shovelnose&highlight=lima)


Anyone, feel free to add something of value or correct me if you catch my wrong(s).


Thanks.









...

Our first "lima", from back in 2010:



gular view and insertion of barbels:

 

[ColeFishing]

Awesome ad thank you. Links are very helpful.


Sent from my iPhone using MonsterAquariaNetwork app

 

[thebiggerthebetter]

4 years later... June 14, 2017 update.

Those in OP have been eaten by predators in a 1500 gal a long time ago, I'm guessing silver aros.

Currently I have 18 "LSN" bought in two batches.

Eight from snookn21 about 2 years ago, these have grown from 3" to ~10":

Ten from Mark Chen of Discus Origins, bought about 3 months ago, these have grown from 2" to ~6" already:

From these two batches and from prior tries, I noted that LSN appear susceptible to a mysterious ailment. About 1-2 out of a dozen all of a sudden start losing control over their body and movement, as if central nervous system is affected. They may recover or perish from it after a long while.

Anyone else noted this?

 

[jaws7777]

Are there any tell tale signs that a newb could use to tell the difference between lima and elongatus ?

 

[thebiggerthebetter]

******************** 1 *************************

From this review paper: http://www.mapress.com/zootaxa/2007f/zt01422p029.pdf .....

..... it would appear that the position of the mandibular barbels with respect to the gular apex is the ONLY way remotely feasible for a hobbyist to ID a live fish - find this key/algorithm in the revision, page 8:

Key to species of the pimelodid genus Sorubim:

... S. elongatus ... check the insertion point of inner mental barbels - it should be anterior to gular apex... if not keep following the key until you hit S. lima

********************* 2 *************************

http://www.planetcatfish.com/forum/viewtopic.php?f=13&t=30938&hilit=+lima - As you could see, our colleague Back (high level hobbyist) from Finland thinks the position of the mandibular barbels with respect to the gular and other skull features may be telling, based on this paper.

http://www.monsterfishkeepers.com/f...1-SPECIES!!!&highlight=elongatus+lima+article

http://www.monsterfishkeepers.com/f...as-valid&highlight=elongatus+lima+differences

http://www.monsterfishkeepers.com/f...-thread-and-updates/page3&highlight=elongatus - page 3 especially

 

[jaws7777]

Is their any benefit to keeping these in a group vs single ?

 

[thebiggerthebetter]

Huge difference in all aspects, including aesthetics. IME and IMO.

 

[thebiggerthebetter]

The 10 younger and 8 older LSN got united about 4-5 months ago. They are all 10"-12" now. The older ones are thicker, for the most part and slightly bigger:

I need to make pictures when they all swim in unison at roughly 45 degrees to the bottom. It's a splendid sight.

They like their sinking and floating catfish farm pellets (Zeigler Bros) and cut bait fish.

I notice they shed a lot or maybe it's because there are a lot of them in there. The tank is #42, 240 gal.

************************************

Got two more from snookn21 at $10 each about a month ago at 3"-4" - still stubbornly hoping to score a true lima haha if I buy enough of them maybe haha... They are in a different tank with all the juvies.

 

[kendragon]

Wow...incredible video! Fish look awesome.

 

[moe214]

You catfish fanatic lol