Cross breed catfish

[doesdavid]

I have a crossbreed of a tiger shovlenose and a redtail catfish, and I am wondering if crossbreeds are being given names or not. It has a shorter nose the a regular shovlenose, the markings of a shovlenose, but a rounder red tail. As I said are these just halfbreeds, or are they named. Are they like other animal crossbreeds and go through several generations before becoming a reconized breed.

DAve

[Silurus]

Hybrids are not given scientific names, so this remains unnamed.

[Birger]

Are they like other animal crossbreeds and go through several generations before becoming a reconized breed.

A "recognized breed" is is different than a species
To use the horse (Equus caballus) for example, there are many different so called "breeds" but all are Equus caballus, the breeds are generally combinations of different genetic traits.
But if you were to cross two species, a horse(Equus caballus) with a donkey(Equus asinus) you get a mule(or a hinny) which is a hybrid.

[Richard B]

Birger puts it very well

If you produce a liger or tigon (male lion, female tiger & male tiger female lion respectively) it has a "title" namely liger or tigon but it has no name - by that we mean the scientific or latin name identifying a species - it isn't a species & can only have some 'crude' title - like (syno hybrid sp 1) which we take to be the euptera x multipunctata cross

[Bas Pels]

although not familiar with the system (I detest h. as much as any other on this forum) I once read a convention is used for h. forms

(lating name of father) X (lating name of mother) [something] if I remember correctly

thus, a tigron would be Panthera tigris x Panthera leo 'tigron' - or so. In this case the tiger cuold be further defined by referring to the subspecies

[doesdavid]

I apoligize to all for the use of word "breed" instead of species. Thank you for your info Silurus . I guess the question should have been " at what point does a 'mixed/cross species' become reconized as a new species. I know that some people prefer only nature's work of mixing/crossing species, while other's will reconize what some refer to as a man made species.
Again I apoligize for using the wrong terminoligy.

DAve

[MatsP]

I apoligize to all for the use of word "breed" instead of species. Thank you for your info Silurus . I guess the question should have been " at what point does a 'mixed/cross species' become reconized as a new species. I know that some people prefer only nature's work of mixing/crossing species, while other's will reconize what some refer to as a man made species.
Again I apoligize for using the wrong terminoligy.

DAve

In my uneducated understanding [I'm no Silurus], hybrids do not (or at least VERY rarely) occur naturally without human influence. If natural hybridization was a common case, the two species would eventually end up being a single species [assuming the offspring is fertile]. So, there is no "process" for making a species from a hybrid - they are hybrids.

Most species do not cross in nature for one of several reasons:
1. They are not naturally occurring in the same place at the same time.
2. They do not give off "sex appeal" to the other species (or otherwise do not "attract" the other part).
3. The male can not fertilize the female's egg.
4. Spawning triggers are not at the same time.

Humans have a way of using hormones and surgical procedures to produce hybrids that do not occur in nature - that way making a female gravid with eggs where the natural environment wouldn't.

--
Mats

[Bas Pels]

now we have a different question.

I know of 1 species which originates from a hybrid, Xiphophorus clemenciae. This swordtail (very pretty) was described rather recently (after 1990) and as far as I know, later it was found it is a hybrid.

It does, however, breed true, and perhaps this might explain why it is still recognized as a species. Another thing is, the species was not man made.

A last remark, species are species because they are recognized. It could be a species is recognized because it is not challenged, and it is not challenged because the most critical people work in an other field - thus they never read about the species. Therefore, it could be a hybrid lifebearer species can go without challenge, while a hybrid catfish species would be challenged

[mummymonkey]

The hybrid origin of X. clemenciae was discussed in this paper - "Hybrid origin of a swordtail species (Teleostei: Xiphophorus clemenciae) driven by sexual selection." Meyer A, Salzburger W, Schartl M.
A relative Poecillia formosa - the Amazon molly (named after the tribe of women, not the river) is also believed to be the result of natural hybridisation. See "The origin and evolution of a unisexual hybrid: Poecilia formosa." - Lampert KP, Schartl M.
I'm sure I read something about hybrid speciation events in Malawi cichlids somewhere too.

Once you get down into the unicellular world hybridisation and other ways of swapping genes (so-called horizontal gene transfer) is common and perhaps even the normal way for species to form. See this months New Scientistfor details

[mummymonkey]

Still on X. clemenciae it is known to be a rather sickly swordtail and very much less fecund than its close relatives. Most aquarists who keep it report that lines eventully die out. As said though it is a pretty fish. Here is one of mine from a few years ago:

[Mike_Noren]

It seems nearly all livebearers are able to hybridize and produce viable offspring.
For instance I some months ago made the mistake of holding Poecilia caucana together with Limia nigrofasciata, so now instead of two interesting and fairly rare species of livebearer I have a booming population of bastards which have no other use than as live food for other fish.

[Bas Pels]

I could help you to some P caucana, but you would have to pick them up

Indeed many lifebearers risk hybridisation, but as far as I kinow, Poecilia and Xiphophorus can be combined without such risk - in fact, as very prolific shortfin mollies have protected many Xipho's during their first days from canibalism - I would advise such a combination

[madmarine]

i will tell you that that catfish has a common name as far as distrubitors go it has been name the leopard cat and they sell to the lfs for about 6 dollars each so as to weather you all agree or not it has been given a name may not be scientfic but it is out there

[Richard B]

a common or trade name of 'leopard' catfish is applied to over a dozen different fish ranging from predatory monsters to miniscule community fish - so if anyone buys a leopard cat they might not get what they wanted!!! Due to the same name being used for different fish.

a Corydoras ambiacus (for example) is a corydoras ambiacus all over the world

[Viktor Jarikov]

As Mats once noted to me, which stroke me by its simplicity: any spotty fish can be called a leopard fish, e.g., by the local fishermen, and any stripey fish can be called zebra fish...

...and any speckled fish may be called "freckles"... (this is from me now)...

...but names as such are meaningless... to the rest of the world and maybe even to a fishing community 10 miles away...

[racoll]

So, there is no "process" for making a species from a hybrid - they are hybrids.

I'm sure I read something about hybrid speciation events in Malawi cichlids somewhere too.

Speciation through hybridisation is indeed a known phenomenon, but generally assumed to be rare. See study below, published just the other day.

In the case of deliberately mad-made hybrid fishes for the pet trade, these aren't natural, so cannot be regarded as different species.

The TSN/RTC hybrids are best referred to by the notation Bas Pels stated earlier.


Stemshorn K.C., et al. 2011. Rapid formation of distinct hybrid lineages after secondary contact of two fish species (Cottus sp.). Molecular Ecology. DOI: 10.1111/j.1365-294X.2010.04997.x

Abstract
Homoploid hybridization after secondary contact between related species can lead to mixtures of genotypes which have the potential for rapid adaptation to new environmental conditions. Here, we focus on a case where anthropogenic changes within the past 200 years have allowed the hybridization between two fish species (Cottus rhenanus and Cottus perifretum) in the Netherlands. Specifically, we address the question of the dynamics of the emergence of these hybrids and invasion of the river systems. Using a set of 81 mostly ancestry-informative SNP markers, as well as broad sample coverage in and around the area of the initial contact, we find a structured hybrid swarm with at least three distinct hybrid lineages that have emerged out of this secondary contact situation. We show that genetically coherent groups can occur at geographically distant locations, while geographically adjacent groups can be genetically different, indicating that some form of reproductive isolation between the lineages is already effective. Using a newly developed modelling approach, we test the relative influence of founding admixture, drift and migration on the allele compositions of the sampling sites. We find that the allele frequency distributions can best be explained if continued gene flow between the parental species and the hybrid lineages is invoked. Genome mapping of the invasive lineage in the Rhine shows that major chromosomal rearrangements were not involved in creating this distinct lineage. Our results show that hybridization after secondary contact can quickly lead to multiple independent new lineages that have the capacity to form hybrid species.

[Richard B]

I was talking to an old chap in the lfs where i used to work, one of their customers. He has recently had some breding success with corys - well done i thought, until he said it was from a sterbai and adolfoi.. I asked if he meant he had bred both species & he said yes, together and he had a couple of fry survive in his community tank