PlanetCatfish.com

http://www.planetcatfish.com/common/spe ... es_id=1949

I think the first pic is of the usual TSN (fasciatum) x RTC (called hybrid #1 in the same list) whilst the second is of Leiarius marmoratus x RTC.

Pros, cons, other opinions?

Anyone? (Somewhat related post http://www.planetcatfish.com/forum/view ... 10&t=40300 )

I'd agree with your assessment, Viktor.

Hi Viktor,

Hybrids are always murky territory, I sort of had it in my head that when two species are crossed, then sometimes the hybrids look more like on species than the other. In which case there could be two "species" entries in the cat-elog. One, in this case, for the hybrid that looks a bit more RTC and one for the hyrbid that looks a bit more TSN if you get my drift.

I don't have a problem moving the second image, but I need to have a bit more of a think/debate about this classification point. I agree that the TSN RTC hybrid that looks more TSN, should probably be in Pseudoplatystoma. However that then makes me wonder about hybrids that involve two genera being in their own (hybrid) genus...

Much to ponder!



Jools

Thanks Rob and Jools.

I hear your dilemma, Jools. I've heard and read others say "this hybrid has more of that parent", etc. Yet, in my eye, which is quite crude and does not pick up things nearly as I wish, the well-known hybrids are rather straightforward to ID and all look roughly the same with rather insignificant variations (EDIT: meaning within each hybrid... obviously not that ALL hybrids look the same). I am speaking of large-catfish hybrids, not synos, whose hybridization world is way, way murkier-looking (EDIT: meaning often hard to ID).

What we need is more help from the community in terms of donating pics of fish of various ages. Then we can chew on something. As of now, I agree, it is almost pointless to keep moving the few hybrid pics around the Cat-eLog.

Besides, most high-level folks on PCF are turned off by hybrids, myself included. In what I differ, is that I'd like to know who is who still and why they are made (e.g., deco vs. food) - that'd be useful in my Aquarium activities.

We'd need help from MFK-ers... but of course, one cannot and should not force a collaboration on either community.

Let the chips fall as they will.

I am easy. I don't feel ignored Thanks for paying attention and explaining as a gentleman that you are.

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In this particular case though, since TSNxRTC are so well known and if pic #1 is thought of as being of one, it should be simply combined with the rest of the pics for this hybrid, which is really the best-known one in our trade out of the large-cat hybrids.

I am speaking of large-catfish hybrids, not synos, whose hybridization world is way, way murkier-looking.

With the Syno hybrids though...they are all still in the genus, Synodontis...making it easy to go Synodontis hybrid 1,2 or 3 etc.
Woe to us if they(whoever they are) start mixing synos with claroteids or something like that.

Birger

Assuming you have read this http://www.planetcatfish.com/shanesworl ... cle_id=180 and Lee's refs as well.

There is a body of aquaculture literature on the topic, but be advised it is mainly in Spanish and Portuguese. Unlike the Syno hybrids, which are created for "esthetic" reasons, the various pim, doradid, pangasiid, and clariid hybrids all are by products of food aquaculture programs that make their way to ornamental fish exporters.

There is an argument that there is a place for these hybrids in the hobby that goes like this: Only the most amateur, uneducated aquarist buys "monster" fish that can not be cared for in captivity. The animals are destined to die because of this. Therefore better these folks kill one of these Frankenstein fish every few months than an actual real species taken from the wild that can not be replaced.

-Shane

Thanks, guys!

Shane, what's your thought on the point of slight incoherence (?) between Jools and I?

Do you see, with your trained eye, two more or less distinct groups of looking-more-like-mom and looking-more-like-dad hybrids? Taking TSNxRTC as the best known and most photographed hybrid as an example could help clarify this point. I agree that there is some degree of variability in that hybrid's appearance but, in general, I have no problem ID-ing these at the first glance.

I've read your piece. What are Lee's references?

Since you asked my opinion...

Hybrids always look like hybrids in a consistent manner. Cross a horse and a donkey and you get a mule. You do not sometimes get something that looks like a horse and sometimes get something that looks like a donkey. To my knowledge this holds true from animals to plants to even corals. So any cross of the same two pimelodid spp should look consistently the same.

As Jools said the entire thing is incredibly murky. I think it is useless to guess at the parentage of a hybrid based on looks alone as a hybrid can look nothing like either parent.

It may be safest, where exact the parentage is not know, to just categorize all of them as "apparent hybrid."

-Shane

Apologies for slightly off-topic pedantic point but you only get a mule from a horse x donkey cross if the mother is a horse. If the mother is a donkey the hybrid is known as a hinny or a jennett. Apart from size, mules and hinnies look very similar though.

Yes, this supports my point. Mare X jack always makes a mule and stallion X jenny always makes a hinny. These hybrids do not sometimes turn out more like a horse and others more like a donkey they always have the characteristics of either mules or hinnies. The physical characteristics of the hybrid offspring remain consistent.
-Shane