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Minute dei meeting
The Cichlid from the desert; Herichthys minckleyi
|A cura di Juan Miguel Artigas Azas, 1996.|
JuanMi says: Good evening, I have considered about chairing this meeting to let you know about a fascinating and not commonly known cichlid that inhabits the desert springs in Cuatro Cienegas de Carranza, a interesting place found in the Chihuahuan desert in northern México. This unique area is a center of many biological studies, and has also been described as a "living laboratory". The specie in question is Herichthys minckleyi.
JuanMi says: Of the fourteen fish species (eight endemic) that inhabits the valley, it is Herichthys minckleyi the species that has attracted attention to a greater extent, giving its very interesting evolution history. This cichlid is considered to be a polymorphic specie with three different morphs, all inhabiting conspecifically to a certain extent in the valley water bodies.
JuanMi says: On the basis of the traditional taxonomy, back in 1974, scientists studying the fish fauna of the valley suggested that the magnitude of the differences found among different morphs of this cichlid, provided more than enough basis for the erection of at least three different species. Smaller differences among congeneric cichlids have been enough for this action to be taken in many other cases. The studies showed three cichlids of different morphology, with two different types of pharyngeal mill teeth and different gut lengths.
JuanMi says: These three morphs have certain specialization, one morph, the most widely distributed and most likely the ancestor of the other two, has the longest intestine and feeds on organic detritus, as well as opportunistically on arthropods that fall on the water. The second morph, somewhat more restricted in distribution, preys on the rich valley fauna of aquatic snails, which crushes with its powerful musculature and well adapted pharyngeal mill. The third of the morphs, with a more restricted distribution, and a mixed dentition, has developed an elongated body shape that helps it in his piscivorous habits.
JuanMi says:Posterior studies on the fish biology started to show amazing facts non first seen, it was discovered that the three different so called morphs of this fish, would interbreed between them in the areas were they concur, and that the producing spring are a split between the two morphs involved. Not an hybridization after all. Fry with intermediate characters between the morphs were present in an insignificant percentage.
JuanMi says: Genetic studies on the morphs resulted in fascinating discoveries as well. Electrophoresis (Genetic affinity) tests showed that the genetic variation among the morphs did no matched what would have to be expected between different species, but it was too small to guarantee speciation. it was concluded after posterior studies that the differentiation had taken place through polymorphism and not speciation.
JuanMi says: Kornfield and Taylor concluded in 1983 with the scientific description of the Cuatro Cienegas cichlid, considering it a polymorphic species and naming it Cichlasoma minckleyi, specific name given after the scientist that more and for longer time has studied the fish fauna of the valley, Wayne Minckley.
JuanMi says: It is fascinating to note that Herichthys minckleyi three morphs are not only morphologically divergent from each other, but also behaviorally. In observations I have carried out in the springs, I have witnessed very special and specific behaviors of the morphs. Like the fact that the molluscivorous morph would swim close to the springs bottom trying to find snails with the help of its acute hearing system, and dressing their body with a black coloration while doing this. The piscivorous morph does disguise its coloration mimicking shadows on the bottom while rest hidden on the substrate waiting for an unsuspecting prey to come by.
JuanMi says: The environment where Herichthys minckleyi is found is very particular. It is formed by warm crystalline water springs with visibility generally greater than twenty meters and with very stable temperatures, which allows them to breed throughout the year. Some parts of the habitat however, are characterized by cooler water of more fluctuating temperature, breeding season in those areas is limited to dry season warmer months.
JuanMi says: The springs are found in the middle of a flat desert landscape, full of vascular plants and short cactae, and sorrounded by the impressive nude rocky ridges around the valley. It has been recorded that the annual pluvial precipitation in the zone do not exceed 300 mm. Water absorbed quickly by the porous calcareous soil of the valley. It is also known that the origin of the water is not from the valley itself. Most springs are restricted to the surrounding skirts on the San Marcos and Pinos ridge tip in Cuatro Cienegas.
JuanMi says: Herichthys minckleyi is to a certain extent a gregarious fish, forming groups and colonies for feeding and living in the springs. Non-breeding Territories will be inhabited by a large amount of fish, most of which will be ignored by the dominant male in it. This male can be tell apart normally by the presence of a muchal hump on their forehead, as well as a darker coloration. In the territories a big amount of fish can be found as I mentioned. The majority of which will be female cichlids or non dominant males. An adult male of Herichthys minckleyi is not however very large, reaching no more than 18 to 20 centimeters (7-8 inches) in total length.
JuanMi says: The cichlids of Cuatro Cienegas form also territories for their reproduction, with no difference among the morphs. A female in a territory will court the dominant male, and both will select a place in it to place their spawn. The place will be commonly chosen on a vertical surface close to the shore of the spring or a cave will be dig in the detritus under a rock, until a solid surface is obtained. Males will turn dark almost black in coloration while females will become snow white, with just some five or six black blotches aligned in the posterior half on the flanks. Males may serve simultaneously several females during breeding time, even females from different morphs.
JuanMi says: Adhesive yellowish eggs are placed on a vertical or inverted surface by the female, and are immediately fertilized by the male. Each spawn of an adult female will number more than 500 eggs, no larger than approximately 20 mm in size. Hatch occurs after two days and the wrigglers are kept until free swimming stage, something like four or five days, in the bottom of the spawning place or one pre-dug pit for protection from pedrators, like the endemic nocturnal catfish Ictalurus lupus. The female will stay close to the spawn all of the time, while the male will surround the territory.
JuanMi says: Males most of the times will abandon females once fry become free swimming, and so the females will be the only responsible of watching over the fry. They will guide them throughout the habitat bottom with spasmodic movements of fins and body, while the fry will feed on the organic detritus and small edible particles. When they become large enough to do by themselves (around 20 mm), they will start abandoning the mother and obtain shelter under the overhanging vegetation on the edges of the springs, from where they venture out for food till they get a large size.
JuanMi says: Aquarium keeping and breeding is possible for this fish, although the large quarters required for congeneric cichlids, like Herichthys cyanoguttatus (Texas cichlid) or Herichthys carpintis, are necessary. I am talking of at least 400 liters (100 gallons), and larger tanks would be more suitable to observe a normal behavior of the fish. This cichlid shows the aggressive attitude of large Central American cichlids, and so steps for controlling its behavior have to be taken, in order to avoid many fatalities. It is always better to keep a group of several size fish if this is possible. Breeding size will be reached before the second year of age.
JuanMi says: Food will be no problem, as this fish is a voracious eater. The molluscivorus morph will quickly forget its habits and will eagerly take any food offered. One should not forget the piscivorous nature of one of the morphs, so very small fish should be avoided in their company. It is my opinion that very high protein foods should be used with care, you should remember this fish inhabits a desert, where food not very plentiful. Over feeding with hard to digest meals could be a sure ask for digestive troubles. Water quality should NOT be ignored, Cuatro Cienegas water quality couldn't be better. Chemical parameters are on the alkaline side with a moderated to high hardness, although this fish is rather flexible in this regard. Temperature is fine from 25 to over 30 Celsius. El mojarral spring has a constant temperature of 34 Celsius (93.2 F), with a yearly variation of less than a degree.
JuanMi says: The Cuatro Cienegas valley, is without a doubt a patrimony of humanity. Recently (November 1994), the valley has been decreed by the Mexican government as a "Protected fauna and flora area". Something that could probably will not be enough to avoid the risks that face the life in the valley. It is probably just a matter of time that some well meaning but bad informed aquarist introduce some exotic species in the springs, something that could have a disastrous effect in their ecology. The lowering of the water table in the valley as a result of over exploitation of the water reservoir for human uses, is also an imminent risk and has caused already important ecological effects in many areas in the deserts of northern México and southern United states. For all this, this valley deserves our attention, compression and protection. Nature and future generations will be grateful to us.
JuanMi says: For those of you interested I will advice to visit the excellent home page on the Cuatro Cienegas de Carranza valley maintained by Peter Unmack and the Desert Fishes Council, the URL is: http://www.utexas.edu/depts/tnhc/.www/fish/dfc/geograph/mex/coa/4cienega/cc_top.php
JuanMi says: Thanks for your attention, I do open now the floor in case any of you would like to make any questions.
MrKillie raises his hand.
JuanMi says: Matt
MrKillie says: JuanMi, if the various morphs can commingle like you described for breeding then is it the case that fry do not 'specialize' until some point late in their development? Have there been studies to pinpoint when the fry specializes and what causes it?
MrKillie says: it seems like the populations are not that far apart, 'geographically speaking'.
JuanMi says: That is an interesting question, whether fry is specialized or not at born it is not clear, I am not aware of studies in that direction, although I would favor they are born specialized, as you will only get fry of the two parent morphs in a given spawn.
MrKillie asks: but there's a small percentage of 'unspecialized' fry, right?
JuanMi says: Yes, about 6% according to studies, I don't know if they would later interbreed with another morphs and what the results could be, but in any case according to my own observations of the cichlid population in Cuatro Cienegas, they are not significant in quantity, barely noticed after all.
Allan raises his hand.
JuanMi says: Al?
Allan asks: is this species the "Sonoran" cichlid I saw at the Arizona Desert Museum in Tucson, or is it related to it? If not, have you heard of this species?
JuanMi says: You are talking about Cichlasoma beani, a entirely different fish Al
Allan says: OK, cool.
JuanMi says: That fish inhabits the pacific slope in México from Sonora to Nayarit, it is not closely related to minckleyi either Apistogramma raises his hand....
JuaMi asks: Ted?
Apistogramma says: do you know of a source of this cichlid in the states? I have never seen this fish alive.....
JuanMi says: Gary Kratochvil kept and bred this fish for some time, he has told me he stop doing it, but he may know who still keeps it. Another source could be Milo Manden from Chicago, who has also kept and bred this fish.
Richardb raises his hand.
JuaMi asks: Richard?
Richardb asks: You mentioned that when breeding, both the male and female change color. How rapidly does this change occur, and how long does it last?
JuanMi says: It may go pretty quick Richard, I have seen individuals changing coloration completely in no more than ten seconds, this concerns to the piscivorurs morph disguising. The color of breeding individuals however, remains for all the breeding effort, that may go to one month or one month and a half.
Richardb says: Thanks Juan.
JuanMi says: You are welcome
MrKillie raises his hand.
JuaMi asks: Matt?
MrKillie says: if in fact the fish is so mutable that you can vary the type of adult you get from how you feed the fry, what does that say about how fish, esp. cichlids, are classified? Don't they have to revisit some basic assumptions, since dentition is a key to classification?
JuanMi says: Well, the fry all eat organic detritus, specialization begin as the fish grow, as is the case in many piscivorus cichlids, who start out eating something else.
JuanMi says: About classification
JuanMi says: Some opinions (which I tend to believe) state that this fish may be in an early stage of speciation
MrKillie says: but then, you can't be sure *at all* even what genus it is.
JuanMi says: You are right Matt, in the past, and many times, (Neetroplus nematopus, Herichthys carpintis, and more) have been set apart on the basis of dentition, even at generic level. That needs to be changed, it is the tendency now to be more in this regard. Some scientists no longer consider dentition or thropic characters as valid genus splitters.
DeanH raises his hand hand.
JuaMi asks: Dean?
DeanH says: I'm a bit surprised to hear you calling this fish _Herichthys_ minckleyi.
MrKillie was eventually going to ask about that, too :-)
JuanMi says: Well, that is a good question
DeanH says: When I first talked to Irv Kornfield about this fish (I'd like to say three years ago but counting it was over five) I also called it _Herichthys_ because it certainly looks like on in coloration but he said it was _Nandopsis_.
DeanH says: Of course, who knows how the dust will settle after Miller's talks this summer.
JuanMi says: First... disclaimer I am not qualified to classify this or any other fish, but....
JuanMi says: Second.. The basic pattern of coloration belongs to Herichthys , as you know, Nandopsis will be restricted by Miller to Antilles cichlids, so it won't be available to continental fish. The basic breeding coloration belongs to Herichthys.
JuanMi says: Third... It has been proved by electrophoresis that the genetic variation with Herichthys cyanoguttatus is that corresponding to sibling species.
JuanMi says: Besides...
JuanMi says: Upper the Cuatro Cienegas basin, in the Ocampo valley, where the habitat is not as specialized as in Cuatro Cienegas de Carranza, guess what cichlid you find...
JuanMi says: Herichthys cyanoguttatus of course, as well as lower in the basin in the Rio Salado. It is not unlikely they were connected in the past. We are talking about distances no more that 30 kilometers either way.
MrKillie asks: could it be a relic population of cyanoguttatus?
JuanMi says: Yes, there is the possibility that H. minckleyi stems from cyanoguttatus after all, in an special environment where it was forced to evolve in different directions.
JuanMi says: we have to consider however...
JuanMi says: That Herichthys as a genus is very poorly described, considering just the dentition in the diagnosis, something that, as we have discussed, could be no longer valid. Scientists will have to work out that, maybe Miller already did.
DeanH says: I didn't know about the electrophoretic data you mention. I'm afraid my information on this fish is somewhat dated.
JuanMi says: Kornfield, L. Irving & Koehn, K. Richard, 1973, "Genetic Variation and Speciation in New World Cichlids", Evolution, 29 September 1975, pp. 427-437.
DeanH says: Thanks for the reference, I'll look it up. I was still going by what Kornfield originally said when he compared it to labridens, bartoni, and steindachneri.
MrKillie asks: Is that why Axelrod uses it for everything that he doesn't use 'Cichlasoma' for?
JuanMi says: He uses "Herichthys" because is the "next" valid genus described after heros, restricted by Kullander in 1985. He has his point in doing that. Although there are valid genus described Posteriorly to Herichthys , like Paraneetroplus , Theraphs and Thorichthys. Those were restricted by Regan to sections of Cichlasoma in 1905.
DeanH says: I had thought that the presence of H. cyanoguttatus in the Cuatro Cienegas basin was due to recent introduction.
JuanMi says: Not at all, is has been written so Dean, but I have just find H. cyanoguttatus in the farther spring in the valley, Laguna Santa Tecla, and maybe some close by lagoons. There you also find Xiphophorus gordoni, A fish with its origin in rivers were Herichthys cyanoguttatus inhabits.
JuanMi says: There is a irrigation channel going out from the valley from that spring, so it could be considered that H. cyanoguttatus arrived that way, but there is not H. minckleyi in such lagoon. So this is arguable.
DeanH says: I'm also glad to hear the personal observations. That is why I'm glad to be able to make this meeting.
JuanMi says: Well, about bartoni first..
JuanMi says: In its basic color pattern Bartoni does not match any gulf basin stream cichlid. But rather match more closely 'Cichlasoma' beani, that could not be surprise. As in the Rioverde valley springs you also find Ataeniobious toweri, a goodie!, those have their evolution center in the Rio Lerma-Santiago, flowing to the pacific. So there may have been some connection in the past.
JuanMi says: Labridens and steindachneri deserve a lecture by themselves
DeanH says: I'll be here for that one too.
JuanMi says: I believe they share enough traits for a genus to be erected, including molluscivorous, insectivorous and piscivorous again. lets see what the scientist say
JuaMi asks: Any more questions?
DeanH raises his hand.
JuanMi says: dean?
DeanH says: Well, if nobody else wants to ask more, I will.
JuanMi says: Sure
DeanH says: Have there been any captive breeding studies to see just what proportion of fry get thrown by what crosses of morphs? I know Kornfield was interested in seeing these done, I just don't know if it ever happened.
JuanMi says: Not that I am aware of, there has been however studies concerning breeding patterns, less than 6 percent of the fry is intermediate between the morphs involved
JuanMi says: There is also one interesting fact...
JuanMi says: Some pair choosing studies by Kornfield show that the pairs seem to choose mates randomly concerning the morph, although they also state that the number of specimen samples is not enough to be any conclusive. For speciation to occur, fish will have to be more selective in the future.
DeanH says: Okay, thanks.
JuanMi says: If you hold on I will give you the reference dean
DeanH says: Okay, I'll hold for a minute.
JuanMi says: * Kornfield, L. Irving, Smith, David , Gacnon, P.S. & Taylor, Jeffrey , 1982, "The Cichlid Fishes of Cuatro Cienegas, México: Direct Evidence of Conspecificity among Distinct Trophic Morphs", Evolution, 36(4)
DeanH says: Good, thanks for the reference.
JuaMi asks: Any other question?
DeanH asks: The other question I have is, to go back to my outdated knowledge, in the original description, K & T talk about two body forms and two tooth morphs. Is this still how this is broken down?
JuanMi says: Yes, the elongated form may have two different tooth morphs, although both will eat fish, it seems the dentition should not be that specialized for fish eating.
JuanMi says: It is interesting to note the restricted distribution of the piscivorurs morph, to three or four thermal springs around the tip of the San Marcos and Pinos ridge. This could show that it was the last morph to evolve. As it is found were the other two morphs are present.
JuanMi says: There are also some distinctive head shape between the molluscivorous and the detritivorus morphs. You can tell them apart easily. Besides the fact that the molluscivous morph can be easily spotted from above due to their massive pharyngeal musculature.
JuanMi says: Another question Dean? ( I will be happy to answer if I can)
DeanH says: Actually, just one more.
JuanMi says: Sure
DeanH asks: Is there a link to the desert fishes council page from the GMC page?
JuanMi says: yes in the minckleyi index. Also you can find a link in the Cichlid room home page http://www.petsforum.com/cichlidroom/
JuanMi says: Well, I want to thank you all being here tonight
DeanH says: Thanks for the talk. It was great.
JuanMi says: Thanks Dean, I am really honored you are here
Richardb says: Thanks for a fascinating talk Juan.
JuanMi says: Thanks Richard
Richardb cheers enthusiastically.
DeanH cheers enthusiastically.
DeanH says: Thanks for inviting me.
Annissa says: WOOOOHOOOOOO! JUAN! great talk :)
JuanMi says: Thanks Annissa
Stevenp says: bye all...Good talk Juan...very interesting
JuanMi says: Thanks Steven, great you were here
Stevenp fades slowly from sight to the delicate strains of a far away flute.
© Copyright 1996 Juan Miguel Artigas Azas, all rights reserved
Artigas Azas, Juan Miguel. (Maggio 27, 1996). "The Cichlid from the desert; Herichthys minckleyi". The Cichlid Room Companion. URL consultato in data Maggio 21, 2013, da: http://www.cichlidae.com/article.php?id=302&lang=it.