A. cf. citrinellus - A potential case of F1 Midevils?

RD.

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Hopefully this works this time .......



I was reading Jason's sticky on midas vs red devils the other day & while I agree with pretty much everything that he posted, according to some of the most recent studies that have taken place in the various crater lakes I'm beginning to think that this is a far more complicated issue than simply being able to rely on reputable vendors.

In his sticky Jason states;



"Trying to determine the identity of an adult fish is difficult enough, but these fish as juveniles look very similar to one another.

Here's the problem with these questions. It is impossible to simply eyeball a fully grown adult fish and determine 100% if it's A. labiatum or A. citrinellum."




I concur with both points, which has me wondering exactly how does a collector/exporter and/or their various workers differentiate between all of these various amphilophus, when the experts can't even seem to agree as to how all of these various fish should be classified? Over the years we have gone from 2 species under the midas complex, later to three species, now recently to 9 species, with the caveat of even more species that have yet to be identified & properly classified. If one compares some of the examples shown in the midas/RD sticky and posted by mou86afa, even those fish don't all conform to what is supposedly typical body structure between the two species. There are very elongated & low bodied labiatus shown (such as in the first row), and some labiatus that are very high bodied. (such as the one shown in the last row) From what I have been able to gather this is far more complex than simply a case of intraspecific variation.



This high variability in body structure or form may be explained due to what has been described as a high level of genetic differentiation between populations of same species from the different crater lakes.





In the first paper linked to below they mention A. citrinellus types with elongated bodies, and some with thick lips. This seems to be a reoccurring pattern among the various studies performed over the past few years. While A. labiatus has morphed (longer head, compressed body, and fleshy lips) due to it's specialized feeding technique of feeding on invertebrates and crustaceans found within the rock crannies, apparently some of the A. citrinellus types share some of these same physical characteristics.

The authors also state that geographically distant populations within the large lakes showed some degree of genetic differentiation as well. Perhaps someone with a more thorough understanding of genetics can help explain some of this in layman terms.



Phylogeography, colonization and population history of the Midas cichlid species complex (Amphilophus spp.) in the Nicaraguan crater lakes

Marta Barluenga, Axel Meyer



http://www.biomedcentral.com/content/pdf/1471-2148-10-326.pdf





Future research on additional morphological characters such as body shape, trophic structures or coloration and genetic differentiation might lead to future descriptions of several thick-lipped species in those crater lakes.






The following study demonstrates that even the jaw structure can be different between the same species (citrinellum), found in the different crater lakes.

Publishing, Ltd.

The Midas cichlid species complex: incipient sympatric speciation in Nicaraguan cichlid fishes? MARTA BARLUENGA and AXEL MEYER

Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457 Konstanz, Germany



http://www.evolutionsbiologie.uni-konstanz.de/pdf1-182/P159.pdf



Two different types of pharyngeal jaws have been described in A. citrinellus: papilliform and molariform. For both A. labiatus and A. zaliosus only papilliform pharyngeal jaws have been described previously in the literature (Meyer 1989, 1990a,b). All A. citrinellus individuals sampled in L. Managua, Tisma Pond and L. Masaya had papilliform pharyngeal jaws (see also Meyer 1990a). All A. citrinellus individuals collected in Ometepe in L. Nicaragua had molariform pharyngeal jaws. Among samples of A. citrinellus that were collected from L. Xiloá, L. Apoyo (A. zaliosus) and Isletas, L. Nicaragua both trophic morphs were found in sympatry. This study provides the first evidence of molariform pharyngeal jaws on fish from Lake Apoyo.




Jaw structure becomes relevant in this discussion as per A. Meyer's paper where he states molariform morphs having blunter, shorter snouts, larger eyes, wider heads, and deeper shorter bodies than papilliform morphs.



http://www.evolutionsbiologie.uni-konstanz.de/pdf1-182/P006.pdf



Cost of morphological specialization: feeding performance of the two morphs in the trophically polymorphic cichlid fish,Cichlasoma citrinellum



The pharyngeal jaw structure in C. citrinellum is correlated with differences in external morphology (Fig. 1, Meyer 1988). Molariform morphs have blunter, shorter snouts, larger eyes, wider heads, and deeper shorter bodies than papilliform morphs.




In the following paper (2010), Jeffrey McCrary et al go so far as to state that one should only assign taxonomically valid species names to unambiguously identifiable individuals and not to each phenotype that is similar due to only one character, i.e. ‘‘elongate body form” or ‘‘thick lips”



Not a simple case – A first comprehensive phylogenetic hypothesis for the Midas cichlid complex in Nicaragua (Teleostei: Cichlidae: Amphilophus)



Matthias F. Geiger, Jeffrey K. McCrary, Ulrich K. Schliewen



http://www.gaianicaragua.org/Geiger_et_al_2010.pdf





4.3. Three species vs. multi-species concept with notes on diversity

While previous and also some recent authors distinguished between
a number of species based on morphological characters (e.g.
Elmer et al., 2010b; Meek, 1907; McKaye et al., 2002; Stauffer et al.,
2008), other authors assign numerous forms to only three species,
namely A. citrinellus, A. zaliosus and A. labiatus (Wilson et al., 2000;
Barluenga et al., 2004, 2006a; Bunje et al., 2007).

The ongoing dispute about Amphilophus taxonomy (e.g. Villa, 1976b; Stauffer et al., 2002) is certainly based on the aforementioned high phenotypic diversity within the Midas cichlid complex which sometimes hampers
ready identification in the field.

To consider this issue adequately especially when testing for alternative speciation scenarios it is necessary to stick to a conservative taxonomy and only assign taxonomically valid species names to unambiguously identifiable individuals and not to each phenotype that is similar due to only one character, i.e. ‘‘elongate body form” or ‘‘thick lips”

According to the most recent taxonomy, the Midas cichlid complex
contains nine described species at the moment, but several more
are awaiting their proper systematic treatment (McKaye et al.,
2002, Geiger et al., in preparation)."



The group of researchers in the paper below have taken the same cautious approach, using A. cf. citrinellus to describe this group of fish until further taxonomic work has been completed.



Local variation and parallel evolution: morphological and genetic diversity across a species complex of neotropical crate lake cichlid fishes

Kathryn R. Elmer, Henrik Kusche, Topi K. Lehtonen and Axel Meyer



http://rstb.royalsocietypublishing.org/content/365/1547/1763.full.pdf



We expect that more species from the crater lakes will be described in the future and that the taxonomic validity of the original species A. ‘citrinellus’ will need to be revisited. Therefore, we refer to Midas cichlids found in multiple crater lakes as A. cf. citrinellus.




So what does all of this mean?



Given the above information I would think that the best approach when breeding any of the above wild caught species is to ensure that both parent fish come from the same body of water, and in some cases the exact same collection location within that body of water. Short of that you might as well consider the offspring of random pairings as Midevils, just like the ones that are found at your LFS.



I've been compiling some of these papers over the past few years and thought that others might be interested in reading them. If nothing else it certainly adds a new spin to the term Midevil. :)



Cheers
 

aclockworkorange

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Very nice RD. So, to sum it up and dumb it down, you have the potential for "wild caught" "Midas" or "Red Devils" to be mislabeled (no matter what they look like, as you've pointed out they can exhibit the same characteristics), and the potential for even F1 offspring of wild caught fish to be mislabeled and/or hybrids. And furthermore there are potentially many more species than just the two due to the high genetic variability (for the ichthyologists to figure out on that point)?
 

RD.

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I would say that's an accurate summation, Mr. clockwork. :)

Below is a "pair" of fish that were posted a few yrs back on another site, sold to the owner from a very reputable vendor. I have removed the vendors name for obvious reasons.

The owner stated; "these are my pair of wild caught Amphilophus labiatus. I got them from xxx about 3 months ago, they're F0 from Lake Nicaragua."

male




female





 

Modest_Man

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I just sat through 3 hours of systematics of fishes and an ichtheology course...too much text for me to go over right now. Posting this so I'll remember to come back once I'm off work tonight.
 

aclockworkorange

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I just sat through 3 hours of systematics of fishes and an ichtheology course...too much text for me to go over right now. Posting this so I'll remember to come back once I'm off work tonight.
Jerk. ;) I'm at CC for another two quarters. I called and spoke with the head advisor for the program the other day, exceptionally unhelpful woman. Anyway, sorry for the derail, looking forward to your post.
 

aclockworkorange

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That's a possibility with many bodies of water in CA, but from every report I've read it seems to be a very rare thing. But that's really not what RD. is talking about either so I don't know how far off topic we should go. Good idea for another thread though.
 
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