# South American 'groupings'



## dwarfpike (Jan 22, 2008)

*Warning: Many scientific sproutings and arguements to follow. Do not read if you do not enjoy the scientific and taxonomy side of this hobby!!*

Based on an ID thread, *bernie* and I were going back and forth on the 'groupings' within south american cichlids. Rather than clog up the OP's sexing thread with a bunch of back and forth, I thought I'd post the grouping Kullander preposed when he started carving up the new world cichlids. These groups aren't really scientific per se, as there is really nothing between Family and Genus in the Taxonomic Hierarchy ... but these are natural groupings he used when reorganizing the various genena and such. Ie., if you follow the break down of Kullander's genera, then you should also follow these natural groupings. *Note:* This are Kullander's groupings, not mine. I do include my thoughts though. :thumb:

This will probably lead to much headaches and arguements, and I know the science side of the hobby isn't for everyone. Hopefully though I won't get boo'd off the boards. 

All New World Cichlids can be divided into four large assemblies ... The Cichlasomines, The Acaras, The Geophagines, and the ... Others? There isn't really a name for the last one, so I'll use 'Others.' This genera are correct as far as I can gather from reading extensively (for 20+ years now) on original Kullander's works and newer follow ups. This isn't to say I might have one or two out of place, I am sure I have missed a paper here and there but this is reconstructed given all the materia I've read and referanced.

Within each larger group, there are sometimes smaller natural groupings as well (ie blue acara group in the Acaras for blue acaras, green acaras, green terrors, and _'Aequidens' biseriatus_ ... Heroine group in the Cichlasomines for sevs, chocolates, ect)

*Cichlasomines:* _Acaronia_, All Central American genera, _Astronotus, Australoheros, Caquetaia, Chaetobranchopsis, Chaetobrnachus, Cichlasoma, Heroina, Heros, Hoplarchus, Hypselecara, Mesonauta, Pterophyllum, Retroculus, Symphysodon, Uaru._

*Acara:* _Aequidens, 'Aequidens', Bujurquina, Cleithracara, Crenicara, Dicrossus, Guianacara, Ivanacara, Krobia, Laetacara, Mazarunia, Nannacara, Taeniacara, Tahuantinsyoa._

*Geophagine:* _Acarichthys, Apistogramma, Apistogrammoides, Biotodoma, Biotoecus, Geophagus, 'Geophagus', Gymnogeophagus, Microgeophagus, Satanoperca._

*Others:* _Cichla, Crenicichla, Telocichla._

The first three are all believed to be decended from a now extinct Cichlasomine. That last group are more closely related to a few African Genera than they are any of the other South American or Central American genera (that threw me for a loop!). Currently, the oldest/most baseline cichlid ... believed to be closest to that orginal Cichlasomine ancestor is of course, the port cichlids, genus _Cichlasoma_.

Hotly debated genera within the groupings:

_Cichlasoma_: Most people consider these acaras for the simple reason about 4 of the 12 species, including the port cichlid (_Cichlasoma portalegrensis_) were previously Acara/Aequidens. But two things to remember here. Those species were only put in _Aequidens_ by Regan based soley on their anal fin count, not any other diagnostic evidence. And two, the original cichlid, and basis for the _Cichlasoma_ genus is another port cichlid, _Cichlasoma bimaculatum_ - more commonly known as the black port or black acara. So despite their common names, Kullander believes them to be the closest living thing to that original, baseline Cichlasoma.

_Laetacara_: A recent study has mentioned this genus is closer to the baseline Cichlasomas than they are to any Acara group genus, but nothing further was mentioned. I haven't yet tracked down that report, but am trying to. Until something else comes out, these should still be considered an Acara group.

_Guianacara_: This is the biggest mislabeled genus. Becuase of their behavior and shape, most consider these to be an earthearter. Indeed, even Kullander shifted them from _Aequidens_ (an acara genus) to _Acarichthys_ (a geophagine genus) at one point. However, when he did more detailed work on the genus, he found they lacked a lobe on the first gill arch, a prerequisite diagnostic to be included in the Geophagine grouping ... thus the acara grouping. While you can have the gill arch and not be a Geophagine cichlid, to be considered a Geophagine cichlid you need to have that arch. Kullander has stated in a paper that _Guianacara_ are more closely related to _Acarichthys_ than other Acaras. Does this mean we should include it in the Geophagines despite missing the major diagnostic tool that defines the group?

What I think we are seeing here (my personal opinion) is the evolutionary emergance of the Geophagine cichlids from the acaras. Ie., _Guianacara_ are the most Geophagine-like of the acaras, and _Acarichthys_ is the most Acara- Geophagine (while it does have the arch, it is not as developed as other Geo's).

_Retroculus_: This one stumps me. In a newer paper, Kullander provided DNA evidence stating that this genus is a Cichlasomine, indeed much closer to _Cichlasoma_ than to any Geo genera. Despite having the gill arch needed for inclusion for the Geophagines, as well as the _Satanoperca_ like shape ... these are now believed to be a result of convergant evolution (differant fish in similiar type areas devoloping similiar evolutions) versus direct evolution (decended from eartheaters). Can't say I agree much with this one but ...

_Petenia_ - Many people believe, due to the unique mouth shape of the bay snooks (compared to other central americans), these are more closely related to _Cichla_ than to the Cichlasomines. Currently all Central American genera are of Cichlasomine decent (yes, there are two species that are not, one an acara - _'Aequidens' coeruleopunctatus_ and one an Geophagine - _'Geophagus' crassilabris_ ... both are acknowledged as migratating up from South America). The mouth shape is not much differant than the basketmouths (_Acaronia_) and false basketmouths (_Caquetaia_), both in the Cichlasomine tribe.

Any discourse welcome, but no 'boo the science' posts please. Remember, these groupings are really subjective, as stated early there is nothing listed between Family and Genus levels in the Taxonomic Heirachy. Sorry for the headaches and probably soon to be arguements!!


----------



## bernie comeau (Feb 19, 2007)

Very intersting to me. Many things I did not know.

By the way, these groupings between family( Cichladae) and genera do have terms. The larger grouping are often referred to as sub-family and groupings with in a sub-family are often called tribes.

Suprising to me that what is now Cichlasoma would be a Cichlasomine, rather then an acara. To me a port acara and a blue acara, as well as a green terror, are all fairly similar fishes. But of course apearances can be deceiving. As well, an oscar a Cichlasomine :lol: I really see the fish as great big acara.

As far as Cichla being more closely related to the African, Heterochromis multidens, then it is to other SA, my understanding is that, that is based only on morphology. From what I understand, recent DNA work shows H. multidens to be closer to Haplochromine and Tilapine then it is to any SA. But of course like most things in cichlid taxonomy, very little is absolutely certain.

As well, some question wether or not 'Geophagus' is closer to a Cichlasomine then it is to a real Geophagus. Many years ago, "G". brasiliensis was successfully crossed with a CA Veija, producing offspring though I do not know if the offspring were fertile. Sort of wonder if it were a real geophagine if this would be possible?


----------



## dwarfpike (Jan 22, 2008)

A few genera threw me as well *bernie* ... both oscars and true basketmouths (_Acaronia_) seem to have more of that classic acara shape ... what I think is happening (this is my guess, not anything from Kullander) is we see the ports being kind of the leaping off point for both acaras and cichlasomines ... I agree body shape alone I'd put them with acaras.

I think acaras derieved from them on one side, the other the acara/port shaped cichlasomines (like the oscar and basketmouth) and continued down to the more specialized forms.

Ie., while chocolate cichlids are deffinately in the Heroine tribe (I knew I was forgetting this level, thanks for reminding me! :lol: ), they have a more acara like shape. I would surmise they were the oldest of the Heroine, aka closer to the ports.

Also I think part of the problem is the termnology changes when the genera were restricted. Ie., centrals were long though to be herione but once that genus/tribe was restricted to the laterally compressed south americans/sevs ... we obviously can't use it anymore for the CA's.

Your brasiliensis complex is another intruiging one. While the _Guianacara/Acrichthys_ might be one evolutionary explaination for the Geo's ... a brasiliensis/cichlasomine one could be another. They do have the gill arch, but it's is not well developed. Could the geo's seperate evolved from both other groups?

Am trying to track down the paper that states pikes and cichla are closer to africans. I am rather curious as to what it says and how I can disagree with it!! :lol:


----------



## bernie comeau (Feb 19, 2007)

dwarfpike said:


> Ie., while chocolate cichlids are deffinately in the Heroine tribe (I knew I was forgetting this level, thanks for reminding me! :lol: ), they have a more acara like shape. I would surmise they were the oldest of the Heroine, aka closer to the ports.


Yeah, could be.But to me, apearance wise, the chocalates have more similarity to sevs (Heros sp.) and true parrots (Hoplarchus psittacus). I know behavoir wise they are very similar to severums. When ever I kept the 2 together, they always hung with each other like they were the same kind. But with CA, my tanks got too rough and sevs always ended up taking out what they got from others onto the chocalate. Today, I know they don't really belong or work well with very large aggressive CA.

As far as another Cichlasomine that, at least to my eyes, can look very similar to a port cichlid, mature chanchitto species do seem to be at least somewhat similar. I think Austroloheros would probably be the closest to a port, at least amongst the Cichlasomines. Though, I'm still not convinced that port cichlids are not more closely related to the other acaras.


----------



## Joels fish (Nov 17, 2007)

:zz: :zz: :zz: :lol: seriously though, this is pretty interesting. Naturally though it does make you wonder( or at least it makes me wonder) which Africans are most closely related to the Ports? Obviously there is a common ancestry between the new and old world cichlids but I would be curious to see which group would take the prize for it.

*dwarfpike* you certainly did your home work on this, good stuff :thumb:


----------



## CHK (Jan 12, 2007)

:thumb: Good summary and discussion. Unfortunately, I only loosely follow the taxonamy and so would not be helpful towards your hot contested topics 

I will, however, follow the thread for interesting observations and education


----------



## dwarfpike (Jan 22, 2008)

Joels fish said:


> *dwarfpike* you certainly did your home work on this, good stuff :thumb:


Actually, I was just bored! :lol:

It was *bernie*'s and I conversation on that poor ID thread that sparked it though.

*CHK* - I of course love the taxonomy part of it, but sometimes it's fun just to speculate. Like how when you post an ID for _Australoheros_ most people think it's a Central American Rainbow or something in the convict family. Would make one think they should be in the same grouping as the Central Americans ... but sometimes the looks can fool you ie those _Retroculus_. I just like chasing down the relationships becuase I think it helps us keep the fish better. :thumb:

*bernie* - oh I agree the chocolates are deffinately heroine, I just meant they aren't as compressed as the other members are ... making me think they are the most primative of the group.


----------



## blairo1 (May 7, 2006)

It's too early so I don't really have many thoughts on this right now, but what I do have to add you may find quite interesting, especially the implications.

Taxonomy has really progressed - recently a group of ichthyologist/taxonomists - Musilova, Z., Rican, O., Janko, K. and Novak, J. conducted a molecular phylogeny of the Cichlasomatini (published 2008). They were looking at Cichlasomatini as defined by Kullander and were analysing specific mitochondrial and nuclear genes, in doing so they were able track the rates of mutation and genetic change, finding that the genera Cichlasomatini are monophyletic, with the exception of Aequidens.

They also conducted research using morphological traits and this was set against the genetic findings, some data obviously agreed and some greatly differed, but they made some seemingly solid (work-in-progress) findings. A fantastic summary of this was printed in the *BCA Cichlidae journal* (vol 29, No 5) in which the summary of the paper (as I will write out here) was written by *Ian Watson*. Original paper - _Molecular Phylogenetics and Evolution_.

I really think that there are some large shifts ahead in the field of taxonomy, as we are better able to understand and trace the genetic lineage than ever before do we disagree and remain stubborn or will we allow ourselves to accept the changes that come from new methods and findings. I for one try to remain very open minded - after all at present our current understanding can only be as reliable (and fallible) as the next discovery. No wonder it's such a heated debate, the solution to which is usually some amount of regrouping (which I know some of you love). :lol:

On to the summary. The clade findings will be written in blue:

Aequidens sensu strictu is paraphyletic (ie it contains taxa which appear to be similar but which are actually derived from different ancestors and so cannot be placed in the same genus). Some Cichlasoma (within its current, very restricted definition) are included in Aequidens. The authors term this the CA clade. 
The CA clade. According to Kullander (1998), Cichlasoma and Aequidens are very similar and well diagnosed genera. While the data presented in the paper supports their close relationship, the genus Aequidens appears to be paraphyletic (even after excluding A. pataroensis from the analysis.)

Krobia is not closely related to Bujurquina, but does include the Guyanan Aequidens sp (A. potaroensis and probably A. paleomeunsis). The authors terms this the KA clade;
The KA clade. The data presented in the paper clearly suggests the inclusion of the Guyanan Aequidens species (represented by A potaroensis in this study) in the genus Krobia.

Bujurquina and Tahuantinsuyoa are sister taxa and are closely related to the 'A.' pulcher and 'A.' rivulatus groups. The authors term this the BTA clade;
The BTA clade. Bujurquina and Yahuantinsuyoa are sister taxa and are closely related to the 'Aequidens' pulcher and 'Aequidens' rivulatus groups. Obviously the latter two groups cannot be retained within the genus Aequidens and their generic placement needs to be resolved, probably by the creation of a new genus to contain these species.

Nannacara and Ivanacara plus Cleithracara form another sister group termed the NIC clade;
My first published picture, of my Cleithracara, was used in this article !!The data presented did neither support nor reject the newly established genus Ivanacara.

Acaronia and Laetacara evolved early on in the development of the Cichlasomatini, which probably arose around 44 million years ago.
Acaronia and Laetacara are thought to be sister genera to the BTA clade.

It should be noted that the authors did not examine specimens from all the species which may currently be contained in the above genera and thus their results should be regarded as work in progress. Adding in data from new taxa may change the phylogenies which result from the analysis. Three differing forms of analysis were applied to the data and it is reassuring they provided similar results, the only real differences being where Krobia ended up in the phylogeny (and those which are its closest relatives) and in the arrangement of the NIC clade. The differences are quite small however and do not detract from the overall conclusions of the paper.

As mentioned the authors found all genera except Aequidens to be monophyletic and thus likely to be "real" genera with genuine evolutionary links to the species they contain. Two groups resolved from 'Aequidens' stood out as different and clearly belonging in other genera. These were the 'A.' pulcher and 'A.' rivulatus groups which stand out as being paraphyletic and unrelated to the Aequidens species in the CA clade.

The authors also carried out a biogeographic analysis of the Cichlosomatini and it is quite hard to describe this as it is graphically based. Reassuringly the species and generic grouping identified by the molecular analysis tend to be reflected in the biogeography which suggests that the various clades did actually evolve in defined, geographic areas.

Pretty fascinating stuff and if you ask me we are only at the beginning of a reshuffle (to what extent is hard to say), as we learn more about the genetic evolutionary background and relationships of once grouped genera.


----------



## dogofwar (Apr 5, 2004)

There are a variety of logical ways to group these fish: by "niche", feeding strategy, breeding strategy, less specialized to more specialized, etc.

Does anyone know if there is any kind of graphical representation of the evolution of the groups?

I'm thinking of a family tree kind of thing showing less specialized to more specialized...


----------



## RyanR (Apr 29, 2008)

Anyone know if there's been a more recent molecular phylogeny for South Americans than this one by Concheiro PÃ©rez et al, 2007?:

http://striweb.si.edu/publications/PDFs ... 91-110.pdf

-Ryan


----------



## bernie comeau (Feb 19, 2007)

As one can see from Blairo1 post, Cichlasoma and Aequidens are not only considered to be both part of the same sub-family (Cichlasomatini) but also to make up the same tribe ( CA clade).

So, in other words, the common name "Acara" , from the old and now defunct genus, is just as aplicable to a blue acara as it is to a port ACARA :lol: , as it would be to any others in this grouping.


----------



## dwarfpike (Jan 22, 2008)

Actually, when you combine *Blair*'s post with the link *Ryan* posted up, it seems the 'Acara' group is now defunct!!! Doesn't even exist anymore!!! Wow, I figured DNA would mess with the old structuring but not quite to this extent.

"I have a bad feeling about this." :lol:

Anyone else find it ironic that the common name (at least in the western US) traditionally for _Cichlasoma portalegrensis_ was 'port cichlid' even though it was in _Aequidens_ for most of it's existance ... while _Cichlasoma bimaculatum_'s common name (again around here) was 'black acara' even though they were always in _Cichlasoma_??? :lol:


----------



## RyanR (Apr 29, 2008)

dwarfpike said:


> Actually, when you combine *Blair*'s post with the link *Ryan* posted up, it seems the 'Acara' group is now defunct!!! Doesn't even exist anymore!!! Wow, I figured DNA would mess with the old structuring but not quite to this extent.
> 
> "I have a bad feeling about this." :lol:


...or maybe everything is an acara! :lol:

-Ryan


----------



## edburress (Jun 9, 2007)

I think I lose sleep over this sort of discussion... might be an indicator of a nerd :lol:

*dwarfpike*... could you send me a link to the _Retroculus_ paper?

For me, assembling the groups together to where the evolution of the fishes can be understood is important, but the fine details are less import because "species" and these groups are human creations and sometimes make it difficult to see how it really works and how groups are really related. For example, I believe _Guianacara_ and _Acarichthys_ are an evolutionary link between the Acaras and _Geophaginae_. I would strictly exclude _Guianacara_ from the _Geophaginae_ because it lacks the lobe on the first gill arch, but Acarichthys could go either way because it has the lobe, but I think it is unimportant exactly where it is placed (closer to Acara or_Geophaginae_). I think it is less likely that '_Geophagus_" is as important as _Acarichthys_ in the evolution of the eartheaters. I do however, see '_Geophagus_' being more important concerning _Gymnogeophagus_. _Gymnogeophagus_ is another confusing _Genus_ for me, the "naked-gilled" fishes by classification (no scales on gill plate) but _rhabdotus_ and _gymnogenys_ groups seem rather unrelated otherwise. A lot of the _rhabdotus_-type look very reminiscent of '_G_.' _brasiliensis_, and they are the only non-G_ymnogeophagus_ eartheater found in _Gymnogeophagus_-rich regions, which supports the theory.



> Am trying to track down the paper that states pikes and cichla are closer to africans. I am rather curious as to what it says and how I can disagree with it!!


I also can't see this being the case. I consider _Crenicichla_ one of the more specialized of the South American Groups, maybe along with _Retroculus_ and _Satanoperca_. If this is true (maybe not, just my opinion) then I would expect them to be the furthest, evolutionarily speaking, from Africans. I'd be interested to read this article if anyone can find it online.

Ed


----------



## RyanR (Apr 29, 2008)

It'd be interesting to see how _Cichla _and _Satanoperca_ fit in with Africans. They're at the base of the phylogeny in the Concheiro PÃ©rez et al, 2007 molecular phylogeny. So evolutionarily, they're fairly basal.

Seems that the break up of Pangea is a big factor in separating the Africans and New Worlds... and that the New Worlds mostly seem to be a monophyletic group, that suggests perhaps a single dispersal event into the New World. Some west African cichlids thrown into the mix would be interesting.

-Ryan


----------



## dogofwar (Apr 5, 2004)

In "Cichlids from Central America" Konings describes the island predators (actually omnivores) like Nandopsis haitiensis and tetracantha as the most primitive (least specialized) and thus the first cichlids in central america (new world?) with more specialized predators, detrivores, and others conquering new territories / niches.

I guess a fundamental question is: did mouthbreeding as a specialized way of breeding develop from a common (new world and old world) ancestor...or did it develop independently (in both places)?


----------



## Joels fish (Nov 17, 2007)

My guess is that it evolved independently. The only reason I say this is that Mouthbrooding is common in the rift lake cichlids and less common in other groups (riverine species), jump to the Americas and while it exists the numbers of true mouthbrooding cichlids is quite small compaired to the Rift valley types. Heroines for instance have species that are substrate spawners and ones that are mouthbrooders. Many Geophagines are mouthbrooders but many are delayed mouthbrooders . I'm not very expert on which species are and aren't ,so if anyone can add to(or correct) this please jump in.


----------



## Number6 (Mar 13, 2003)

Is there any reason to think that New World and Old World cichlids share a fresh water ancestor?

Any evidence? Links?


----------



## DeadFishFloating (Oct 9, 2007)

Number6 said:


> Is there any reason to think that New World and Old World cichlids share a fresh water ancestor?
> 
> Any evidence? Links?


I can not remember where I read it, but I am sure I did read that SA cichlids, and a few other SA fish, evolved from pacific salt water fish. Or it could have been a doco on the Nat Geo channel.

When is comes to science, I haven't a brain in my head, so I'm staying out of this conversation, but reading with interest.


----------



## Number6 (Mar 13, 2003)

DeadFishFloating said:


> I can not remember where I read it, but I am sure I did read that SA cichlids, and a few other SA fish, evolved from pacific salt water fish.


and did salt water fish evolve into cichlid twice? once in the new world and once in the old?

or once long long ago back when Africa and SA were joined?

Kullander had some ideas... later folks disagree... it's the fun of the cichlid world! :thumb:


----------



## DeadFishFloating (Oct 9, 2007)

Well I don't know. I don't know the shape of pangea. I sort of understand how cichlids spread through SA as the article/tv show, which ever it was, explained how cichlids spread with the evolution of SA. But it didn't eplain how cichlids spread through CA.

I have no problem believing they evolved seperatley, seeing as this article in the C-F library, The Evolution of Cichlids, explains how African cichlids evolved, and by the sounds of it, African cichlids may very well have evolved seperately.



> and did salt water fish evolve into cichlid twice? once in the new world and once in the old?


I think this is quite possible as there are many examples in evolution where different species develop along similar lines to fill a similar niche, but originate in different parts of the world, and many thousands of years apart.


----------



## Joels fish (Nov 17, 2007)

I found a little trinket of info on the common ancestry here http://www.springerlink.com/content/cg08vt6e6b2q1ubw/

I'm still looking but it seems most of the reaserch I'm finding is on rift lake cichlid . I supose the origins of cichlids as a whole isn't as intrigueing to that many scientists at the moment :lol: . I'll post more as it's found, but yes it seems there is indeed a fresh water ancestor of both new and old world cichlids but you have to go back a long way to find it.


----------



## Joels fish (Nov 17, 2007)

Here's a much better link, a bit more technical. http://www.biomedcentral.com/1471-2148/8/215


----------



## Number6 (Mar 13, 2003)

Joels fish said:


> but yes it seems there is indeed a fresh water ancestor of both new and old world cichlids but you have to go back a long way to find it.


that's the kullander work being cited... some later papers offered some alternate thoughts...


----------



## RyanR (Apr 29, 2008)

Joels fish said:


> Here's a much better link, a bit more technical. http://www.biomedcentral.com/1471-2148/8/215


Sweeeet paper! Thanks!

FWIW, basically, Pangea ripped apart at the end of the Mesozoic. As the Middle East tried to rip away from Africa, it tried to take a big chunk of northeastern Africa with it, it failed, but process created the rift lakes.

South America and Africa unzipped from north to south, sharing only a connection via Antarctica. So there's a pretty big biogeographic barrier. That all New World Cichlids are "monophyletic" (i.e share a most recent common ancestor with each other than they do anything else), that suggests a single dispersal event from Africa to the New World. Otherwise, we'd find African cichlids mixed up with the New Worlds in the genetic family tree. Since The most basal cichlids are _Etroplus_ and Madagascar cichlids, that suggests that the cichlids originated in Africa. The new rift lakes probably offered a nice clean slate for the family to diversify into all kinds of "niches".

The trend in the New World has the most "basal" genera being South Americans, seems from here they diversified northward into Central America.... Interestingly _Nandopsis_ falls out with South Americans... so it looks like that could represent a separate dispersal northward from SA.

-Ryan


----------



## Joels fish (Nov 17, 2007)

There is a current theory that all CAs are decended from a single dispersal of one or possibly two groups from South America, and only having done so relatively recently compaired the dispersal between Africa and South America. The evidence iseems to be more in favor of the heroines being the pioneers with the Port Acaras being a possible co-pioneer. Or at least thats what I got from it as I scanned through the paper at school today.

Here's the link. http://striweb.si.edu/publications/PDFs/Martin_Bermingham_p1998.pdf


----------



## bernie comeau (Feb 19, 2007)

dwarfpike said:


> Actually, when you combine *Blair*'s post with the link *Ryan* posted up, it seems the 'Acara' group is now defunct!!! Doesn't even exist anymore!!! Wow, I figured DNA would mess with the old structuring but not quite to this extent.
> 
> "I have a bad feeling about this." :lol:
> 
> Anyone else find it ironic that the common name (at least in the western US) traditionally for _Cichlasoma portalegrensis_ was 'port cichlid' even though it was in _Aequidens_ for most of it's existance ... while _Cichlasoma bimaculatum_'s common name (again around here) was 'black acara' even though they were always in _Cichlasoma_??? :lol:


Nah! Whata ya mean? :lol: :lol: the fish was always called Port ACARA. Both species --- Aequidens portalgrensis and Cichlasoma bimaculatum. Here in Canada and all over the U.S.A. The 2 were not distinguished for a long, long time until it became aperant to some that C. bimaculatum also existed in the aquarium hobby trade and differred very slightly from A. portalgrensis.

AND yes, Acara grouping still exists ---- it's called Cichlasomatini -----Cichlasoma and Aequidens both being of the same tribe with at least some mebers of Laetacara also being of the samel tribe ( geez, ya think! duh! :lol: ) Actually i would think an L. curviceps would be even closer to a C. portalgrensis then a A. pulcher or A. rivulatus.


----------



## bernie comeau (Feb 19, 2007)

Number6 said:


> Is there any reason to think that New World and Old World cichlids share a fresh water ancestor?
> 
> Any evidence? Links?


Very good quistion. The Gonwandian ancestory theory is most prevailing, though I know there is no real fossil evidence for it --------- 45 million year old fossil of a jewel cichlid like fish is the oldest cichlid fossil, but Gowandian theory actually predates known fossils of group of fish cichlids are supose to have evolved from!!! ------ so geology and fossil records, so far, actually contradicts gondwandian theory ------- so maybe both new world and old world have some what seperate salt water ancestory? Just a possibility.


----------



## bernie comeau (Feb 19, 2007)

Number6 said:


> Is there any reason to think that New World and Old World cichlids share a fresh water ancestor?
> 
> Any evidence? Links?


Well, yes, there is reason to think that new world and old world cichlids share a fresh water ancestor. Like I mentioned in my last post, the Gondwandian theory is the prevailing theory ---- (though far from the only theory). I will provide no links, as this is off the top of my head, from what I have read over the last number of years :lol:

#1 Distribution ------ cichlids have gondwandian distribution

#2 Both morphology and DNA seem to indicate that cichlids, split first, as known from geology: India with madagascar together, splitting away from Africa (which was then only attatched to South America). Then south america splitting from Africa. Then cichlids colonizing CA and the carribean islands from South America after it formed ( or CA actually split away from S.A. with cichlids already established on CA as some suggest, and then later re-attatched to SA?).

The evidence in support of this theory, is LESS then conclusive. No fossil evidence. In fact the modern group of fishes that cichlids are supposedely evolved from, based on the fossil record, did not yet even exist at the time of the break up of gondwandia. The fossil evidence, at least so far, indicates that cichlids, let alone the advanced type of fishes they evolved from, did not yet even exist at the time of the break up of Gondwandia!

Many salt water dispersal theories exist.( Not to mention the original idea: dispersal across Asia, then down the berring strait- very little support for that today.) Also bear in mind the time it took for Africa and S.A to split apart and the much closer proximity these land masses would have been to each other ( facilitating a salt water dispersal) in the past.


----------



## RyanR (Apr 29, 2008)

The cichlid fossil record is pretty sparse even in SA where we know there should have been cichlids.... I *think* there's a cichlid fossil or two going back into the Mesozoic from Gondwana's heyday. Those of us working on terrestrial vertebrates from the last quarter-billion years have to deal with this problem quite a bit as the terrestrial fossil record is pretty awful compared to the true marine fossil record.

The solution is what's called "ghost lineages", which basically means that these animals must have been around, even though there's no fossil evidence available for that time interval. In short, "absence of evidence isn't evidence of absence". Fossilization is a big time roll of the dice. The odds of a fish in a river being buried and fossilized aren't great to begin with, and actually finding that fossil in the tropical regions is really tough since there's sooooo much vegatation and so little rock exposed.

The evidence of cichlids sharing a common ancestor is pretty solid in terms of both molecular and shared bony features unifying them as a group... so it's pretty safe to say that cichlids didn't evolve twice from two separate saltwater ancestors. Though saltwater probably played a key role. Since all New World cichlids share a more recent common ancestor with each other than they do with the Africans, it suggests that getting to the New World from the Old World was not easy... perhaps because of a saltwater "barrier". Some modern cichlids (like black belts) can handle near marine salinity. It's possible that the ancestor of New World cichlids was able to tolerate the early (and skinny!) Atlantic ocean and disperse to South America.

Another possibility is the Antarctica connection... it wasn't chilly and remote back then. We know that dinosaurs were dispersing to South America from Africa via Antarctica near the end of the Mesozoic.... I just don't know enough about cichlid relationships and and distributions to say much more than that.

-Ryan


----------



## bernie comeau (Feb 19, 2007)

RyanR said:


> I *think* there's a cichlid fossil or two going back into the Mesozoic from Gondwana's heyday.
> 
> -Ryan


Nope. The oldest, is "only" 45 million years old.

http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1088656&blobtype=pdf


----------



## bernie comeau (Feb 19, 2007)

RyanR said:


> so it's pretty safe to say that cichlids didn't evolve twice from two separate saltwater ancestors.
> 
> -Ryan


No, I don't think it's too safe to claim that. Cichlids could be monophylytic -------going back to their saltwater days. Why not? One thing that is generally accepted is that Cichlids originally came from saltwater fishes that migrated to fresh water ------ when this migration occurred is unknown.

After the break up of Africa and S.A., one prevalent saltwater species could have invaded fresh water on both continents and then evolved along similar lines. The same species ------or even possibly numerous, closely related species. Monophyly, is just a question of how far back in time you want to go. Common ancestory, yes, but no reason to think the common ancestory couldn't go back to saltwater. Of course, just one of many possibilities.


----------



## Joels fish (Nov 17, 2007)

> Another possibility is the Antarctica connection... it wasn't chilly and remote back then. We know that dinosaurs were dispersing to South America from Africa via Antarctica near the end of the Mesozoic.... I just don't know enough about cichlid relationships and and distributions to say much more than that.


 True that Antarctica wasn't always as cold and desolate as today, but it was still pretty far south even during the creatatious when it was still a part of gondwanaland. Dinosaurs migration and the current theories about their being warm blooded, coupled with it's milder( but still very cold in the winter) climate goes a long way to answering some of the antarctic dino questions.However I dont think that the early cichlids would have been able to handle the climate as the areas that they should have first emerged and the areas they still occupy are tropical.

I think that the bigger questions are just how ealy did cichlid evolve ,and just how quickly did they spead. The molecular clock data seems to point to a time somewhere close to the early creatatious, giving them plenty of time to disperse across Parts of pangea as well as gondwanaland. The tough part to this is the afore mentioned lack of fossil evidence. Early dispersal would certainly go a long way to avoiding the need to brave the open ocean .


----------



## RyanR (Apr 29, 2008)

Thanks for setting me straight, Bernie! 

I did a quick search and came up with this:

http://www.bioone.org/doi/abs/10.16...:PAANFC]2.0.CO;2?cookieSet=1&journalCode=vrpa

So that puts cichlids in South America in the Eocene as well. I can get the PDF for folks that don't have access to the _Journal of Vertebrate Paleontology_ (I'm actually a member of the Society that publishes the journal). They have this fossil higher up in the New World cichlid clade than _Astronotus_, _Cichla_, and _Crenicichla_, but outside Geophagines and other New Worlds. If they're correct in their placement of the fossil species, this strongly suggests that cichlids were really "happening" well before we see fossil evidence for them in the Eocene. There must be considerable cichlid history not recorded (or yet discovered) in the fossil record.

I'm still sold on the "plate tectonic" theory, since we have cichlids in the New World, Africa, Madagascar, and Aisa. If cichlids weren't around before Gondwana got hopelessly separated, than that would mean what we call cichlids evolved at least four separate times. Molecular divergence times suggest perhaps 90 million years of "unrecorded" cichlid history.... though molecular divergence times are still a little too iffy to frame an opinion on... especially when the fossil record of cichlids is slim pickings at best. 

Dispersal at least to the New World must have been late in the break-up of Gondwana.... since if it were "easy" to get here, New World cichlids would have separate African roots. Instead, it looks like they all share a common ancestor, and all are more closely related to each other than any are to African cichlids.

-Ryan


----------



## bernie comeau (Feb 19, 2007)

Joels fish said:


> > The molecular clock data seems to point to a time somewhere close to the early creatatious, giving them plenty of time to disperse across Parts of pangea as well as gondwanaland.


What I always wonder is just how reliable are these kinds of estimates? I certainly don't know :lol: And it's not supported by a fossil record. Not saying of course, that it's not good evidence ----- but I would really wonder if one could rely on that, with out more evidence.

What is the rate of mutation anyways? :lol: Is it really a constant over time? You have things like crocodiles that suposedely haven't changed much for millions and millions of years and other things like micro-organisms that can evolve very,very rapidly. Natural selection -----something might change a lot over one period of time and not too much over another period of time.


----------



## RyanR (Apr 29, 2008)

bernie comeau said:


> What is the rate of mutation anyways? :lol: Is it really a constant over time? You have things like crocodiles that suposedely haven't changed much for millions and millions of years and other things like micro-organisms that can evolve very,very rapidly. Natural selection -----something might change a lot over one period of time and not too much over another period of time.


You pretty much have the crux of the argument: Constant rate of mutation. That's the big assumption... also there's the assumption that you're looking at part of the genome that's not acted upon by natural selection. Supposedly calibration comes in part from the fossil record. Of course, when there's not much of a cichlid fossil record to go on, the strength of a molecular "clock" in an argument isn't all that great.

-Ryan


----------



## Joels fish (Nov 17, 2007)

Anything prior to 45mya is speculation due to lack of fossil evidence. However with the genetic data some reasonable guesses can be made. The West African rivrine cichlids like the Hemichromis are at least the most similar to the port cichlids and the Heroines are the ancestors of many of the Central american species showing an east west dispersion. The CAs arrived 30mya as evidenced by the fossil record. The kicker is that we can't say much of anything for certain till some one digs up the fossils that show when and where the cichlids arrived. Molecular clocks may not be completely reliable but with the lack of any other evidence they are better than nothing, and may at least give a ball park to start looking in . Also the CAs are believed to have spread across the entirity of meso america in maybe 5 million years or so, so maybe just maybe the early cichlids were able to spread accross gondwanaland long before the land masses broke apart.


----------



## bernie comeau (Feb 19, 2007)

Joels fish said:


> The West African rivrine cichlids like the Hemichromis are at least the most similar to the port cichlids and the Heroines


Well, to us aquarists, Hemichromis species do seem to resemble, somewhat, some of the new world cichlids. But then so do many of the Tilapines. But like every other African cichlid, with the exception of Heterochromis multidens, they are all classified as belonging to the sub-family, Pseudocrilabrinae. The tribe Hemichromini has close relatives in either Tilapinae, Tylochromini or Pelmatochromini, depending on which scientists perspective.

But as far as any African that is seen to be closer to SA/CA cichlids, it is the peculiar African, Heterochromis multidens, that is often seen to be closer to a SA cichlid then it is to other Africans. That is based solely on morphology. Kullander figured it was closest to Cichla species. But recent DNA work has shown it to be closer to Haplochromine and Tilapine, then it is to any SA cichlid.

Tilapine, by the way is NOT monophylytic. The mouth brooding tilapias (Oreochromis, for example) have ancestors from the substrate spawning Tilapias but apear to be more closely related to some Haplochromines then they are to some Tilapias. Anyways, no real reason to think hemichromis species are closer to new world cichlids then Tilapine, Pelmatachromis etc.


----------



## Joels fish (Nov 17, 2007)

Yup Bernie your right, somewhere I had read that they were but that was disproved but not dislodged from my brain :lol: .

What is really needed here is a better understanding of when cichlids arose, where they did it , and where they went and how fast they got there. I lean towards them being more ancient than 45mya because it makes the most sence. Also explains to a degree the genetic seperations of the different groups (new world, african, malagasy and asian) . All the DNA studies in the world don't replace dead fish in rocks  . The concept of them evolving multiple times in different places just doesn't work.


----------



## bernie comeau (Feb 19, 2007)

Joels fish said:


> The concept of them evolving multiple times in different places just doesn't work.


Either way, whether the common ancestor is a freshwater fish or a salt water fish ----- they still evolved along seperate paths in 4 different places :lol:

If you want to look at it as a fresh water ancestor then you have got around 120 million years of SEPERATE evolution, seperating new world and old world. A long time to evolve along very seperate paths. Then you have to explain the monophly of SA/CA cichlids as well as ignore the fossil record that so far shows the group of fishes that cichlids evolved from, did not yet even exist for millions and millions of years.

If you want to look at it as a salt water ancestor ( or a frsh water cichlid that could migrate in salt water) then you have at the LEAST, 30 million years or so, seperating new world cichlids from old world cichlids. Then you have to explain why Madagascar has 2 groups of cichlids ----one related to Africans and the other related to cichlids from India. As well you have to explain wwhy they are found were they are.

Although i must say, Cichlids distribution is not entirely Gondwanian, as African cichlids are found in the middle east all the way into turkey and all the way to Iran, as well as fossils from a warmer period of time in the past, in Europe. As well SA cichlids into CA and CA cichlids into the Carribean Islands.


----------



## Joels fish (Nov 17, 2007)

I have a link to a paper on the CA/SA conection on page two.



> Then you have to explain why Madagascar has 2 groups of cichlids ----one related to Africans and the other related to cichlids from India. As well you have to explain wwhy they are found were they are.


 If you assumetheir origin in gondwanaland, then you can assume this is because of the path of dispersal. Though still possible that one group migrated there before the split was complete at a later time.



> If you want to look at it as a fresh water ancestor then you have got around *120 million years of SEPERATE evolution, seperating new world and old world*. A long time to evolve along very seperate paths. Then you have to explain the monophly of SA/CA cichlids as well as *ignore the fossil record that so far shows the group of fishes that cichlids evolved from, did not yet even exist for millions and millions of years. *


 Yes it is but it does explain the genetic dipairity between to old and new world cichlids. As far as the fossil record goes , lets just say that we can both say it's incomplete. Our own species is a good example of how an incomplete fossil record can cause some trouble with showing the path of evolution. The ancestral fish you refer to could be little more than an offshoot species from the true common ancestor that has yet to be discovered. We were once thought to have evoled from Neanderthals, but it is now known that they are a (now extinct ) sister species. Our true ancestor is H. Ergastor, who spread out of africa into Europe and those became Neanderthal where as the Ergastor that stayed in Africa became us. We can say for certain that this happened before 100,000ya because we were around then, and our sister species was around long before that.


----------



## bernie comeau (Feb 19, 2007)

Joels fish said:


> > If you want to look at it as a fresh water ancestor then you have got around *120 million years of SEPERATE evolution, seperating new world and old world*. A long time to evolve along very seperate paths. Then you have to explain the monophly of SA/CA cichlids as well as *ignore the fossil record that so far shows the group of fishes that cichlids evolved from, did not yet even exist for millions and millions of years. *
> 
> 
> Yes it is but it does explain the genetic dipairity between to old and new world cichlids..


Fine. But then you have sort of a paradox. There is 167 million years since the split up of Africa from Madagascar and India. That's 167 million years of seperate evolution and yet there are madagascar cichlids that are much more closely related to African cichlids. You have 120 million years sperating India from madagascar, yet there are species in India that are closely related to Madagascar cichlids. If the time explains the disparity, how does it explain the close similarity? And why not cichlids in Australia? It was attatched to India and madagascar after it split away from Africa/ SA.

Of course Gondwania is an explantion for the distribution of cichlids on Madagascar -----that's why I mentioned it as something that needs explanation, if the common ancestor is a salt water fish or a migreating cichlid.

And what do you mean the ancestor I refer to could be an offshoot :lol: the only ancestor I refer to is the COMMON ancestor, what ever it may be, which is an unknown.

I am more familiar with Hominid eveolution then cichlid evolution and don't agree much with what you have said in regards to this, and am tempted to debate this :lol: BUT really is very off topic and completely irrelavant to cichlids.


----------



## Joels fish (Nov 17, 2007)

From what I've seen the maps of gondwana show India and madagascar still conected to it 120 -130 million years ago which explains those cichlids , but SA and Africa are still together at this time as well so it's very possible for them to have spread across africa into south america. By 80 mya the continents are fully seperate and each population evolving in isolation .New finds have new world cichlids possibly pre-dating old world cichlids (as far as the fossil record is concerned ) by almost 10 million years. Type Proterocara agentina into your search engine, This little fellow was discovered 4 years ago and the age still hasn't been properly nailed down yet (the best I can find on it is an age range) but is somewhere between 33 and 55.8 million years old. Big spread but at worst it's the oldest new wold fossil by 3 million years and at best it's the oldest fossil cichlid period. and like the name suggests it's from Argentina.

Many things about the fauna of Madagascar make you scratch your head, but quite simply since they were part of the same land mass then you can have a group in Madagascar that are related to Indian and African cichlids. Australia was too far south , or rather that the conection between the cichlid populated area and Australia was by the time cichlids had arose and were spreading out across gondwana. I think a more curious question is why no native cichlid population in Florida, a mere hop skip and barely a jump from Cuba with a native cichlid population and even rest stops along the way.

And the different groups aren't that closely related. Some are more like others but they are more like distant cousins. The most closely related groups are the CA and SA, with the Centrals directly decended from SA ancestors .

And if you want to debate hominid evolution I'd be happy to lock horns :lol: . We should do it on PMs though to keep the forums fish related :wink: .


----------



## bernie comeau (Feb 19, 2007)

Joels fish said:


> Many things about the fauna of Madagascar make you scratch your head, but quite simply since they were part of the same land mass then you can have a group in Madagascar that are related to Indian and African cichlids. Australia was too far south , or rather that the conection between the cichlid populated area and Australia was by the time cichlids had arose and were spreading out across gondwana. I think a more curious question is why no native cichlid population in Florida, a mere hop skip and barely a jump from Cuba with a native cichlid population and even rest stops along the way.


The abscence of Cichlids in Australia is easily explained: it's too far away for cichlids too swim from Africa :lol: It's connection to India and madagascar, for MILLIONS of years should at least, raise some doubts about the Gondwanina distribution of cichlids!

SA/CA cichlids are more distant from Afrincans , maybe because SA was first to be "colonized" by African Cichlids through salt water , not so long after these continets seperated. Just a possibility.

Salt water is NOT a barrier to cichlids. There are cichlids in Africa living in water far more salty then any ocean. ex"C". urophathalmus and V. maculicauda are now , not only living on the coral reef but breeding there. Oreochromis species now have established populations all over tropical salt water coasts in many parts of the world. Competition with other memebers of the sub-order Laboidei is a constraint on the spread of cichlids but in times of rapid climate change, cichlids make 'in-roads'. By the way, all of cichlids close relatives in the sub-order Labroidei, are salt water fish!

Madagascar got colonized twice. First when it was close to India, then a second time, more modern, when it was close to Africa. Again, just a possibility.


----------



## bernie comeau (Feb 19, 2007)

Joels fish said:


> I think a more curious question is why no native cichlid population in Florida, a mere hop skip and barely a jump from Cuba with a native cichlid population and even rest stops along the way.


It's only 12, 000 years since we came out of the last ice age.Cichlids might have alraedy been to Florida long before but are certainly there now, thanks to humans. Of course all it will take is one good, very cold long winter, and they may not be there the next year :lol:


----------



## DeadFishFloating (Oct 9, 2007)

Hey guys, sorry I'm again a little late to this conversation, again.

Like I said earlier, I dislike joining such conversations as I realy do struggle with many scientific concepts, mostly to with math, physics and chemistry.

OK, so I have a question that relates again to a documentary I watched last night.

*Joels fish wrote:*


> The CAs arrived 30mya as evidenced by the fossil record.


Arrived from where? According to the doco I watched last night, South America and Central America only joined up via the Panamanian Isthmus some 10 million years ago at the earliest. Internet sources suggest as late a 3 million years ago.

By the way, the doco was on the spread of North American mamals in South America and vice versa, and the effects both groups had each continants animal populations.


----------



## Joels fish (Nov 17, 2007)

> Arrived from where? According to the doco I watched last night, South America and Central America only joined up via the Panamanian Isthmus some 10 million years ago at the earliest. Internet sources suggest as late a 3 million years ago.


 from where is a good question , but there are fossil cichlids found on the island of Hispanolia (Haiti and Dominican republic) from that time.


----------



## Joels fish (Nov 17, 2007)

> The abscence of Cichlids in Australia is easily explained: it's too far away for cichlids too swim from Africa


 so are cuba and Hispanolia but there are cichlids there but not in the places that would make sence for them to be if they swam there. If they swam to Cuba then there should be populations of native nandopsis all over the gulf coast and not just south of the US. Plus for all we know there may have been a physical barrier that prevented cichlids from migrating to Australia. 


> SA/CA cichlids are more distant from Afrincans , maybe because SA was first to be "colonized" by African Cichlids through salt water , not so long after these continets seperated. Just a possibility


I'll agree that it's possible but I don't think it's that likely. i think it makes a lot more sence that the migrated just before the split or just as it occuring but not yet complete. Given the later , they could satisfy your craving for salty cichlids and mine for not having to cross an open ocean. They could just swim across a bay or estuary. As far as Madagascar being populated twice, I think a more likely explanation is that it was the place where the two groups split and ancestors of both stayed put while part of the population spread into Africa and India ,and the others got seperated when the split occured.


----------



## RyanR (Apr 29, 2008)

FWIW, the fossil record for Coelacanths ends in the Mesozoic..... until one was caught alive and well. That's a 65 million years of missing history at the least.

That there's a fossil cichlid in South America nestled relatively high up (more advanced than _Astronotus, Cichla, and Crenicichla_) in the New World cichlid phylogeny in the Eocene, means that the common ancestor of these guys was in the new world well before the Eocene. Thus, there has to be a pile of missing history.

That there are no true marine cichlids, and that all cichlids have been shown to be monophyletic (every study I've seen) and share several derived characters, really does suggest a common freshwater common ancestor. Yes, the common ancestor could have been saltwater (the ancestor of that ancestor was most assuredly saltwater), and then cichlids (every cichlid) adapted to freshwater habitats four times, but the evidence that we have supports the freshwater ancestry.

As for plate movement, Madagascar's fauna (bugs, mammals, whatever!) has been shown to be relatively recent.... post Cretaceous, surprisingly. So cichlid ancestry doesn't have to go waaaaay back.

Some folks are thinking a SA/Afr connection as late as 90 million years ago, based on dinosaur distributions.... though that still leaves a gap of about 45 million years before we start seeing cichlid fossils.

India's movement was pretty late in the Cretaceous as well, before it peeled and went zipping off, which was crazy fast for a chunk of rock to go zipping over the mantle. It hadn't yet plowed into Asia by the end of the Mesozoic.

-Ryan


----------



## Joels fish (Nov 17, 2007)

The fact that we have any fossils at all(bivalve, gastropod, dinosaur, austrolopithicus, whatever) is a near mirricle in and of itself when you take into account how haphazard the process is. Missing representatives in the fossil record is to be expected. Still though it would be nice to have a few more to help get a better picture of what the early cichlid distrobution was. The molecular clock data may not be the most reliable , and certainly not a road map but does help to point to the "land marks" of approximately when things should have happened, and give a marker of when to look for them in the fossil beds.


----------



## bernie comeau (Feb 19, 2007)

RyanR said:
 

> As for plate movement, Madagascar's fauna (bugs, mammals, whatever!) has been shown to be relatively recent.... post Cretaceous, surprisingly.
> 
> -Ryan


Is that generally thought to be, because Madagascar was actually still attachted to some other land mass, post Cretaceous? Or did much of this fauna migrate. If it's the latter, Cichlids should not be thought to be any different.

You make some very good points RyanR. That these dates for break up of land masses in the past, are not set in stone, does change things considerably. It makes things a lot more recent, possibily. That there is not a concensus (?) on these dates for the split up of what was formerly Gondwana, and that they could have been attatched, at least somewhere for a long time, into more recent times, certainly makes the Gondwana hypothesis more plausible.

My understanding, is that it is competition with established marine fishes that prevents Cichlids from establishing in salt waters, and not because of any inability to tolerate salinity. Similarily, competition with Centrarchids ( and other fishes), plus the colder climate of our last ice age, may have been a barrier for cichlids to invade Florida. As cichlids are certainly found today in east coast drainages all the way up to Texas ----so they are certainly found through out most of the carribean coast.

To be perfectly frank, I'm not set on any of these theories. But given the ability of many cichlids to live and breed in the ocean, I don't see the Gondwanian theory as any more plausible then the idea of a migrating cichlid or a salt water common ancestor.


----------



## Joels fish (Nov 17, 2007)

> Is that generally thought to be, because Madagascar was actually still attachted to some other land mass, post Cretaceous? Or did much of this fauna migrate. If it's the latter, Cichlids should not be thought to be any different.


 Why would that be? Madagascar was connected to Africa and India for a very long time and should have had a number of native species living there already. Is there any evidence to say that something wiped out its early native fauna ?

On another note , it would seem we're in an iteresting position to obsevre first hand the spread of pioneer cichlid species , though they are introduced species. We have introduced cichlids from Texas to Florida and if anyone is paying attention the ability to measure how fast they establish themselves and how quickly the radiate from their initial point of introduction. I know it's far from an ideal setting since any yahoo can dump a bucket of cons in the local waterway but it's certainly better than waiting for thousands or even millions of years for them to maybe work their way north.


----------



## bernie comeau (Feb 19, 2007)

Joels fish said:


> > Is that generally thought to be, because Madagascar was actually still attachted to some other land mass, post Cretaceous? Or did much of this fauna migrate. If it's the latter, Cichlids should not be thought to be any different.
> 
> 
> Why would that be? Madagascar was connected to Africa and India for a very long time and should have had a number of native species living there already. Is there any evidence to say that something wiped out its early native fauna ?


If Madagascars fauna is post Cretaceuos ( in common with Africa? India?), it is quite reasonable to think that Madagascarean Cichlids could be as well , like the rest of the fauna. 
Either Madagascar was still attatched post Cretaceuos, or this fauna migrated. One or the other or maybe even both. If their migrants, not saying , of course, that it wiped out native species, though that is one possibility


----------



## Joels fish (Nov 17, 2007)

But why would all of the fauna be post cretaceous? If that is indeed the case then something would have to have wiped out the pre-existing fauna. There isn't much that can do that in mother natures arsenal except a major catastrophy , and even then there are some survivors. K-T event wipe it out perhaps?


----------



## bernie comeau (Feb 19, 2007)

bernie comeau said:


> Either Madagascar was still attatched post Cretaceuos, or this fauna migrated. One or the other or maybe even both.


Well, since no one is answering my questions, I had to do my own reading :lol: From my little bit of reading on the net, I understand there is a view, (I don't know how widely accepted) that Madagascar and India were still attatched to each other around 60 million years ago or so. Late Cretaceuos or early Paleoscene. Lemurs and some other African animals are thought to be more recent migrants from Africa, because of Madagascars close proximity to Africa. At least that's one explanation for more modern animals that the fossil record is showing in common with Africa.

No where on the net, at least that I can find, is claiming Africa was still attatched to Madagascar and India, any sooner then 165 million years ago ----- that puts it back into the Jurrasic age.


----------



## bernie comeau (Feb 19, 2007)

bernie comeau said:


> or early Paleoscene.


Sorry! Mixed up words :lol: Meant early Cenozoic ( 60 million years ago or so).


----------



## Joels fish (Nov 17, 2007)

I've found a few maps that show it connected and some (recently) that show it only just barely seperated in the early cretatous. However one odd thing is that almost every one of them shows the continents moving away from Madagascar , while it stays more or less in the same spot. The cretaceous maps have India and Madagascar together till about 80MYA and India Madagascar and Africa together till round about 150 MYA . Making an Early cretaceous origin possible and making a brief trip across a very narrow sliver of ocean possible to cross to Africa , as well as a possible trip back across to Madagasca. Provided it was wet and not dry land as the other maps suggest.


----------



## RyanR (Apr 29, 2008)

The geology and paleontology of the southern hemisphere is only now just recently being understood. Just not enough fieldwork had really been done until about 1995 or so, and the results haven't started showing up in the literature until this decade. Most stuff not until the last 5 years. Consequently, understanding the breakup of Gondwana is a *really* hot topic.

Paleomagnetic data (basically looking at the orientation of sand grains in sedimentary rock) will pretty much tell you the latitude that grain of sand was at when it was deposited. The trick is that this is all away from the boarders of the continent... and when big chunks of rock slide around on the mantle, there's always volcanism of some sort at its margins.

In short, we know where the most of a continent was at a given time in the earth's history, but we really lack information about the margins. The best evidence that we have for how and when things were connected come from looking at the relationships and fossils of the flora and fauna. With the new fossils of some ugly looking meat (Abelisaurids) eating dinosaurs and some of the long necked (Titanosaurids) dinosaurs, there's become stronger evidence that India, Madagascar, Africa, and South America likely had connections possibly until the mid Cretaceous.

Still leaves us a pretty big gap of time before we start seeing cichlids in the fossil record. :lol:

One question to think about is why are there no truly marine cichlids? Cichlids are pretty competitive fish. They're smart for fish, and have pretty spiffy parental care strategies. When tossed in ponds in Florida, they trash the native fish. If they somehow were "marine" enough to disperse.... why didn't some species "stick around" in the marine realm?

-Ryan


----------



## Joels fish (Nov 17, 2007)

Very good point *RyanR*. Some tolerate salt water and a few tolerate it really well , but NO true salt water cichlids . Another question is why would cichlids wait till the cenozoic (provided they in fact did evolve in the mesozoic) to disperse , and why would they strike out across open ocean to do it? I cant think of a great number of cichlids that are truely open water fish. Crossing an ocean for no good reason doesn't make much sence.


----------



## wmayes (Oct 22, 2007)

There are two theories I have to respond to *RyanR*:

1) At the time of dispersal cichlids may not have been fully freshwater. They could have retained many salt-water characteristics which would have allowed them to disperse through salt-water. After this, cichlids could have continued evolving to the point where they are today whereby only some species can inhabit salt-water and for only short periods of time.

2) Cichlids could have evolved backwards to be able to inhabit salt-water again to the point where a dispersal was inevitable.

In both examples, the species that remained in salt-water would have gone extinct long ago. As much as we like to think of cichlids as aggressive, they are no match for most salt-water species and would have been out-competed easily.

The issue with argument 1 is that after the dispersal each ancillary group of cichlids could have evolved on a much different path, perhaps not even to a point where they had structures necessary to being classified as what we view as cichlidae.

The issue with argument 2 is similar to the issue with argument 1 except that the differences would be two-fold. First, you have the evolution backwards to a state where salt-water inhabitance is possible (creating a big difference between the evolved and the unevolved cichlids). Then you have travel from Africa to each other area. Second, you have another evolution taking place to inhabit these new areas of freshwater where the chemistry is very very different. The results of such an evolution would likely be drastically different than the first freshwater incursion from cichlids.


----------



## Joels fish (Nov 17, 2007)

> Still leaves us a pretty big gap of time before we start seeing cichlids in the fossil record.


True but vertabrates make the worst fossils . Too many little pieces to get scattered and broken, especially something as delicate as a fish skeleton. It's always possible there are tons of cichlid fossils from way back to the cretaceous that are are sitting in storage in museums and universities that aren't recognized as such because of their poor state of preservation .

*wmayes*
Interesting hypothosis in number one , but you hit the nail right on the head with it's short fall. Cichlids are cichlids no matter where you find them, which all but rules that possibilty out.

#2 makes no real sence. Evolving into a fresh water fish, only to devolve into a salt water fish , and then re adapt to fresh water on another continent is more trouble than mother nature puts into things. A common fresh water ancestor (even if there is no fossil evidence yet found of it ) from gondwana is the most plausible explanation for cichlid dispersal. Also had the early cichlids been true salt water fish then it's very likely they could have made it to Austtralia and set up shop. there are no native cichlids in australia but there are in the other major component land masses of gondwana (barring antartica for obvious reasons).


----------



## wmayes (Oct 22, 2007)

I didn't really believe what I said - I agree that it is way 'over the top'. My point was really just an offhand way of saying this:

The only true possible way that cichlids could have spread is through freshwater environment only. The two options for cichlids emanating through salt-water can easily be disproved.


----------

