Geographical variation in Xenotilapia melanogenys?

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Geographical variation in Xenotilapia melanogenys?

Post by Thomas Andersen » Tue Dec 20, 2005 12:35 am

For an introduction to this topic, please see this paper: http://www.cichlidae.info/section.php?n=tsd&id=114

So, all of you who’s keeping Xenotilapia melanogenys, have you observed differences in the construction of nests?

And likewise, have you observed if the number and position of the black spots in the males dorsal fins differ between different geographical populations or do they differ among males within the same population?

I hope there will be a lot of input on this one! :)

Thomas

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Re: Geographical variation in Xenotilapia melanogenys?

Post by Livio Leoni » Tue Dec 20, 2005 12:33 pm

Dear Thomas
some months ago I asked Ad Konings about the nests of X. melanogenys because a friend of mine saw something similar in aquarium with fishes he collected in the lake (the nest is similar to "kilesa").

Here's his reply:
I have found a variant like that near Kipili and the bowers they make look like that of kilesa. I found there is quite some variation in the bower shape among the various populations of melanogenys. In the south there are no structures inside the bowel, in southern Tanzania there are ridges in the bowel and along the central Tanzanian coast there are small heaps of sand set in a circle in the bowel. Enjoy your cichlids, Ad

In the last lectures about sandwellers, Ad shew some photos of different kind of nest of this species. I saw one of these photos in his latest book.


Livio


Xenos wrote:For an introduction to this topic, please see this paper: http://www.cichlidae.info/section.php?n=tsd&id=114

So, all of you who’s keeping Xenotilapia melanogenys, have you observed differences in the construction of nests?

Thomas

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Post by Thomas Andersen » Tue Dec 20, 2005 1:24 pm

Thanks Livio - very interesting and enlightening!

Yes, I saw the picture of a nest from Kantalamba in Ad´s new BTN Guide to Tanganyika Cichlids and was quite astonished to see a nest with ridges inside - this could get really interesting :D

Thanks a lot,

Thomas

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Post by Livio Leoni » Tue Dec 20, 2005 2:12 pm

The photo I saw is in Celebrating Cichlids.
Livio
Xenos wrote:Thanks Livio - very interesting and enlightening!

Yes, I saw the picture of a nest from Kantalamba in Ad´s new BTN Guide to Tanganyika Cichlids and was quite astonished to see a nest with ridges inside - this could get really interesting :D

Thanks a lot,

Thomas

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Post by Thomas Andersen » Wed Dec 21, 2005 2:19 pm

Livio has already shed light on the nest building of Xenotilapia melanogenys and this really opens up for some interesting aspects

But what about the coloration – are there differences in coloration, e.g. the number and position of the black spots in the dorsal fin or other features, which could be linked to different geographical populations, and maybe even to the different populations we now know exist by the construction of different nests?

All the best,

Thomas

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Post by Livio Leoni » Fri Dec 23, 2005 2:06 am

I think it's important to check the anal fin too (possibly). In some variant the anal fin is white.
Livio
Xenos wrote: But what about the coloration – are there differences in coloration, e.g. the number and position of the black spots in the dorsal fin or other features, which could be linked to different geographical populations, and maybe even to the different populations we now know exist by the construction of different nests?

All the best,

Thomas

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Post by Thomas Andersen » Tue Dec 27, 2005 2:46 pm

Thanks Livio for pointing this out. I’ve also noticed that some males tend to have a yellow or orange blotch on the chin.

I’m trying to get an overview of the different X. melanogenys populations, so if any of you have some pics of your X. melanogenys with known collection place I’d be very interested in seeing them :)

All the best,

Thomas

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Post by stevegreen » Sat Jan 07, 2006 9:52 am

i have been keeping X melanogenys Namanzi for about 9 months and have noticed that the fish will breed without creating a large nest/bower.

if anything i would classify the nest/spawning site as "undefined" . is anyone else seeing this behaviour in there melanogenys ?

Nothing like the C foai "magara" i moved on in order to keep these guy's.


cheers
Steve Green
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Post by Thomas Andersen » Sat Jan 07, 2006 6:12 pm

Thanks for your comment, Steve

Actually I kept a group of X. melanogenys Namansi around a year ago, but sold them a couple of months later - even though they were not full grown the males builded nests while I had them. Tim Nurse has also taken some wonderful pictures at Namansi showing males in their nests: http://www.fishaholics.org/gallery/disp ... =22&pos=32

Your males are still young, so maybe they will start building nests in time :)

All the best,

Thomas

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Post by Thomas Andersen » Sun Jan 08, 2006 9:09 am

I’ve been checking a lot of pictures of X. melanogenys, and it seems that the idea that the black spots in the males dorsal fins could be seen as an expression of different populations, isn’t right as it seems that it varies a lot within individuals of the same population – anyone who is keeping groups of X. melanogenys at the moment, the could confirm this (I’m not keeping any at the moment, so I can´t check myself :wink: ) ?

Also I’m working on a distribution map for different populations of X. melanogenys in the Lake, so I would be very interested to see pictures of your X. melanogenys with known collection place – thanks!

All the best,

Thomas

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Post by Thomas Andersen » Mon Feb 27, 2006 2:35 am

I finally got Ad Konings "Celebrating Cichlids" (amazing book with some fantastic pictures, by the way), which depict a X. melanogenys nest from central Tanzania with small heaps of sand set in a circle. This is really quite interesting; if any of you have some observations in the nest-building of X. melanogenys you would like to share I´d be very interested :)

Thomas

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Post by Thomas Andersen » Thu Mar 08, 2007 3:53 am

I thought I’d kick some life in this thread again with a thought-provoking statement. We now know that different populations of Enantiopus melanogenys constructs differently shaped nest. Should we regards these populations as distinct species? I think it’s not too far off saying that these populations must be reproductively isolated, otherwise the nests would be similar, and it does not seem unlikely that the females recognize the right males by the shape of the constructed nests. We will end up with at least five different Enantiopus then:

Enantiopus melanogenys – soucer-shaped nest without inner structures (type locality Moliro, Congo – I presume it’s similar to the Zambian populations).

Enantiopus sp. “melanogenys kantalamba” – saucer-shaped nest with ridges inside (distributed in southern Tanzania).

Enantiopus sp. “melanogenys kipili” – several small nests excavated, with heaps of sand around the nests (distributed around Kipili, Tanzania).

Enantiopus sp. “melanogenys burundi” – saucer shaped nest with a smaller inner nest (distributed in the northeastern part of the Lake).

Enantiopus sp. “kilesa” – several small nests excavated, with heaps of sand around the nests (distributed on the western shore between Kalamie and Kavalla in Congo - differs in morphology and coloration from the rest of the known E. melanogenys populations).

So, what do you think? Comments are more than welcome :) :wink:

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Post by Mark Smith » Fri Mar 09, 2007 9:32 pm

I am definitely intrigued by such a notion regarding the variants of Enantiopus melanogenys being differing, say cryptic sibling species. We all seem to have accepted that E. sp. "Kilesa" is an undescribed species, but in regards to the others, I cannot say with any certainty. Perhaps the only sure fire way would be to collect wild specimens from each location, and have them studying for their physical properties by a trained, competant ichthyologist?

It reminds me of the subtilties of some species in the lake that look remarkably similar to each other, such as six striped Cyphotilapia from the northern half of the lake vs. C. gibberosa; N. caudopunctatus vs. leloupi, signatus vs laparogramma; ocellatus vs. wauthioni; not to mention the varying Tropheus varieties between and within particular species.

If I may, could not the same be said of the many differing georgraphic color variants of Altolamprologus compressiceps? I have worked with many varieties around the lake, and there seem to be differing body depths, snout protrusion angles, vertical barring patterns, and even spawn sizes. Perhaps this should be started as a new thread?

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Post by Livio Leoni » Sat Mar 10, 2007 8:59 am

Dear Thomas
It's the usual problem of allopatric forms of the cichlids.
In the taxonomy of Malawi Cichlids, behavioural traits are important diagnostic tools for the delimitation of species. I don't know the situation in Tanganyika Cichlids.
About Enantiopus we want a lot of experiments on mate choice under laboratory conditions!!!!
:D :D :D :D :D :D
I have some questions. Do you know the courtship dances of these forms of Enantiopus? Are they similar? Are they associated with differences in nest shape?
Alea iacta est?
:wink: :wink: :wink: :wink: :wink:

Livio
Thomas Andersen wrote:I thought I’d kick some life in this thread again with a thought-provoking statement. We now know that different populations of Enantiopus melanogenys constructs differently shaped nest. Should we regards these populations as distinct species? I think it’s not too far off saying that these populations must be reproductively isolated, otherwise the nests would be similar, and it does not seem unlikely that the females recognize the right males by the shape of the constructed nests. We will end up with at least five different Enantiopus then:
So, what do you think? Comments are more than welcome :) :wink:

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Post by Mark Smith » Sat Mar 10, 2007 9:56 am

Also, lets not forget the sounds that cichlids make. This may also aid in determining whether or not the differing variants of Enantiopus melanogenys are distinct species or not.

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Post by Livio Leoni » Sat Mar 10, 2007 11:50 am

I forgot it!!!!
:o :o
Livio
Mark Smith wrote:Also, lets not forget the sounds that cichlids make. This may also aid in determining whether or not the differing variants of Enantiopus melanogenys are distinct species or not.
Last edited by Livio Leoni on Sun Mar 11, 2007 3:27 am, edited 1 time in total.

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Post by Thomas Andersen » Sun Mar 11, 2007 1:30 am

Thanks for your comments, Mark and Livio

First of all, I of course can not proof anything, it’s just meant as a little mind-game ;)

The different morphology of Altolamprologus could be explained by ecological factors, like slightly different food sources, amount of available food, differences in habitat etc. I completely follow you Mark, and I would not be surprised if more distinct species got recognized someday, but wouldn’t many of the populations hybridize if they got the chance?

The same goes for the genus Tropheus, it undoubtly contain more distinct species than recognized today, but I think many of the Tropheus populations would hybridize if changes in their habitat would allow them to.

I think the case with Enantiopus is different. The shape of the nests must be coded in the genes, or implemented in the brain, if you can say so. If females mated with a random male, the nest would be similar, or there would exist several differently shaped nests within the same locality. This is not the case – different geographical areas contain uniquely shaped nests. To me that’s a strong indication that the females must pick the “right” male she is coded in her genes to choose, and that way uphold the unique population she belongs to – in other words the different populations must be reproductively isolated (I hope this makes some kind of sense, I have a bit of difficulties expressing this clear in English ;) )

Mate choice experiments could be one way of determine if several species of Enantiopus exist, like you proposed Livio, but I think fine scale molecular analysis of different Enantiopus populations could also be an affective tool.

I don’t know if different populations of Enantiopus show different ways of courtship linked to nest shape, but I would not be surprised if they do ;) Anyone with a lot of empty tanks that want to fill them with different Enantiopus populations :lol:

Again, comments are highly welcomed, I think this is quite an interesting discussion

All the best, Thomas

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Post by Estelle » Sun Mar 11, 2007 4:06 pm

A nest of "Kilesa":

Image

Image

The blue spots and orange spots show the two circles of heaps of sand.
Image

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Post by Mark Smith » Mon Mar 12, 2007 11:59 am

Great shot of the next of E. sp. "Kilesa", Estelle!

Thomas, I see what you are saying, and it makes one wonder what is really going on. It would be interesting to find out if each of the differing populations produce different sounds, only recognizable to each race. This might lend more credence to them being distinct species. Of course, being able to observe them all in their natural habitat and noticing possible unique physical behaviors (coupled with the sounds they make) would likely be helpful.

Regarding the Altolamprologus compressiceps around the lake: In regards to the variants I have worked with, I have noticed that the juveniles from some races are more skittish, while others more "normal" in their juvenile behavior patterns. I am not sure what to make of it all, just an observation to present to those interested in this thread. Some races do have more elongated bodies than others, and some have far more blunt, vertically upturned mouths than others, while others do have differing vertical barring on the body.

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Post by Livio Leoni » Mon Mar 12, 2007 2:48 pm

Dear Thomas
According to the latest article about Cyphotilapia (Takahashi, Ngatunga, Jos Snoeks): "In the case of Tanganyikan cichlids, when the allopatric populations do not show any differences in any character other
than color pattern, they are usually treated as a single species
showing local color variations (e.g., species of Ophthalmotilapia,
Cyprichromis, Tropheus; Konings, 1998)."
I don't know very well the colourations of the "species" you propose (except Kilesa), but the nests are different.
Three years ago a friend of mine gave me some wild Enantiopus (11) from different places (Lyamembe...at the moment I don't remember exactly all the localities). All the specimens were fixed in formalin and then preserved in alcohol. Unfortunately it wasn't possible to extract DNA for an analysis.
Livio


Thomas Andersen wrote:Thanks for your comments, Mark and Livio

First of all, I of course can not proof anything, it’s just meant as a little mind-game ;)

All the best, Thomas

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