Two New Australoheros Species

[cichla]

I heard from several people, not just one, that in Brasil ( Brazil is in English) the description of new species are rewarded monetarily. I assume it is the state, perhaps through the cientific entities, who does that.

Well,might be. The 'All catfish species inventory' (for example) was a fund for descriptions of new catfish species.

If politicians are told a certain species is found in a certain area - they assume part of that area can be sacrifised. Were the species in that area splitted into 3 or 4 species, all these species had their own chance of conservation - resulting in more nature left

Same as pointed out by Rico and Juan, I think the impact of ''excessive splitting'' for conservation is more negative than positive. The 'excessive splitting'' based on obscure species concepts is unpleasant for conservation, because an increased number of 'endangered species' requires an increasing number of funds devoted toward conserving such ''species''. It might be that taxpayer and politicians becoming 'tired' to pay attention to every single pond or small river which harbour its own, then endemic, 'species'. Or it may happen that an (then wrong) area is protected just because there is a high number of such 'species'. And areas which harbour a higher 'true' diversity, but a smaller number of 'species', are not protected.

[cichla]

In Figs. 2 and 11 Rican et al. used the neighbour joining (NJ) method for the construction of some the 'trees'. However, the NJ is a distance based cluster analysis and I couldn't find any hint how they calculate the distance matrix. Would be interesting to know how they compute the distance matrix based on the 'Morphological characters in APPENDIX 2.'
In Fig. 2 there are ''posterior probability of 1.00''. Well, it is more philosophical, but I am wondering if it is possible to be 100% sure from a statistical point of view.

[Bas Pels]

If politicians are told a certain species is found in a certain area - they assume part of that area can be sacrifised. Were the species in that area splitted into 3 or 4 species, all these species had their own chance of conservation - resulting in more nature left

This is certainly a valid point, but on a long-term basis this excessive splitting may rather have a negative effect on species (and also habitat) conservation. First of all, if the term 'species' is turned into something useless (and this is certainly the case with species that are in fact only distinguishable by living in different rivers), than this will also apply to species conservation. Second, as politics has much to do with making compromises, it is unlikely that every river system/habitat with supposedly endemic species will be protected. The more such habitats are known, the more the decider in charge will have to select, and many of us have certainly made the experience that this is not necessarily the most competent person in the respective field. This will eventually increase the possibility that a habitat with real faunal pecularities will be put at the risk of destruction because the granted funds have been 'wasted' for a place which actually harbours a widespread fauna.

I was just to say just this, I cant agree more. Excessive splitting can only lead to species concept devaluation, once a species is sacrificed because of the "We can not protected them all, we have to be realistic" argument gets validated (which has been actually been given by politicians and even biologists in Mexico), then the importance of a species in the ecosystem is of less value. All habitat destruction after this can be easily justified.

I do agree with both of you. In fact in my country we have seen a very good example of this - which has nothing to do with fishes, so I won't go into that

Still, I think on an individual level - the scientist writing a paper, that is - it might explain why splitting happens

After all, your very true comments are on a general scale, answering the question whether too much splitting is a good idea.

Bur we see more often something is bad on a large scale, but nevertheless tempting on a smal scale

[Willem Heijns]

Mystery solved!

The non-type material in Říčan & Kullander (2008) for forquilha is presented like this:

ZSM 23482 15/16 and ZSM 23060 6/12.

This means that 15 out of 16 and 6 out 12 (21 in total) specimens in these lots were then thought to belong to forquilha. The other 7 specimens are different (irrelevant for this study) species. This was overlooked by me in my post yesterday.

In Říčan et al (2011) all these 21 specimens are included in ykeregua as non-type material. The split was merely meant to separate the 7 specimens belonging to those "other" species from the ykeregua lots.

The measurements and counts (tables 1 and 2) for forquilha in Říčan & Kullander (2008) are thus to be replaced with the same data for forquilha in Říčan et al (2011) tables 2 and 3.

I would again like to thank Oldrich Říčan for his help in this matter.

[Paulo José Alves]

Hi Mark Smith

The flagrant splitism in american taxonomy is an undeniable fact, not that they are the only ones, some europeans also go in that way. Just an example of that is the fact that in 30 years the number of european species of fish has increased by 300! Europe in terms of biodiversity is poor, is not definitely South America or the South East Asia. Of course what happened is the division in species of variations that would not deserve that treatment. Nonetheless in America this is taken to a higer level and consistently, minimal diferences are enough to constitute a new species. I would take as example Cyprinodon, Simpsonichthys and Rivulus, these 3 genus of killies have an incredible number of species based on not very discernible variations.In generall terms most of the european taxonomists are not spliters but that is also relative. What I usually say to make my point about the absurdity of this proliferation of false species is if we would aply to human beings the same criteria there would be 3 or 4 species and not just one. The blacks would for sure be considered a different species, black color, small morfological differences, original geografical distribution very well established, that would be more than enough, of course we know that is not true.
We aquarium fish amateurs are just that amateurs, but our brains didn´t just stop working, we know what we are talking about, it´s a lot of years studying and observing fish, we know something about we are talking about. Due to that it´s clear that the parameters of species definition has still a lot to evolve and clarify, what we see doesn´t allways coincides with what the professionals say and they might be wrong.
Recently 3 new species of cyprinids were described in Portugal, they are impossible to distinguish visually, the only way is to observe in a microscope some obscure difference in the scales. Today I have less hair than I had years ago, of course that must mean that I am now a different species than I was years ago ...

All The Best
Paulo José

[Paulo José Alves]

Hi Bas

Australoherus facetus exists in Portugal since the 1940`s acording to most sources, a friend biologist believes that it´s as you say since more than 100 years ago. I tend to believe the prevailing tesis of the 60 or so years. Anyway, that is not enough time to make the portuguese specimens very different from their ancestors in South America, evolution takes time. It´s impossible for me to distinguish our specimens from others caught recently in Uruguay, I see absolutely no difference.

All The Best
Paulo José

[Bas Pels]

Hi Paulo

Sometimes evolution can go very rapidly, but the fact you don't see any differences tells me evolution apparently did not do so in this case.

OK

[Rico Morgenstern]

I don't see how can captive conditions could have affected the fish is such a way, particularly as they surely have not spent many generations (if any) in aquarium.

My assumption is in part based on own observations on other species. I had, for example, offspring from one and the same pair of Nandopsis tetracanthus. Some developed very strong, large jaws, with the lower distinctly projecting, while others had smaller mouths with the lower jaw only slightly prognathous. My only explaination is that this has to do with the different food composition. The large-mouthed fish did appear when growth differences led to canibalism; they were the largest fish feeding partly on their sibs. When I later hat sufficient live food such as Chaoborus larvae and cladocerans, the fry did grow more uniformly and did not develop such large jaws.

You may also read the following paper, which proofs the view that jaw morphology may be influenced by food:

http://www.evolutionsbiologie.uni-konstanz.de/pdf1-182/P003.pdf

Of course, such observations raise the question to which extent this character is at all suitable for diagnosing species.

[Juan Artigas]

Thanks Rico,

I was more referring about the speed of the change, not to the actual possibility of it, of which I have as well seen several examples. Of course we know that cichlids are such a successful organisms because of their great adaptive plasticity.

If we are to accept that the males on the pictures developed their prognathous appearance because of short term captive keeping, we could as well accept that the female actually loss her prognathous appearance for the same reason, which in the end would make us agree that the mouth morphology would be useless as a diagnostic character for that group of species. I don't personally think this could be true in a relative short term.

In regards to your N. tetracanthus, we must nor forget that some species (certainly N. tetracanthus as the only cichlid in its distribution) have a varied genetic expression in terms of their morphology, that in the end leads them to speciation. We know that N. tetracanthus has this varied expression both inter- as intra-populations.

The fact that the prognathous mouth has been used more than a hundred years ago as a diagnostic character for Australoheros facetus and remains not challenged so far, would make me doubt that this character has such plasticity for that species, which apparently inhabits a much more competitive environment than N. tetracanthus, and hence requires more specialization to survive.

[Rico Morgenstern]

Actually, the prognathous lower jaw was not used as a diagnostic character of A. facetus before Rican & Kullander (2008). Regan (1905) was the first to recognize the present genus Australoheros as a taxonomic group (his "section 3" of the genus Cichlosoma). C. facetum was diagnosed against the two other included species C. autochthon and C. oblongum by having the fold of the lower lip not continous. Haseman (1911) found this character variable even in specimens from one and the same locality. Consequently he recognized only a single species, Cichlasoma facetum. This view was not challenged until at least the 1980s, the first other species recognized 'formally' was 'Cichlasoma' tembe in 1995. Furthermore, we must not forget that the paper of Rican & Kullander did not include the taxa of Eastern Brazil. Therefore, we should not give too much weight to this one character.

Likewise, I would doubt that A. facetus is more specialized than N. tetracanthus, not to mention Parachromis managuensis (see link in my last post).

[Juan Artigas]

I read the paper and it is quite interesting, although it does not contradict what I expressed before in terms of some species potentially being more prone to fast plasticity adaption than others (although as I said all certainly are given enough time and the conditions that promote it). Thanks for suggesting it Rico. It is an argument more of why we should be careful on accepting new species whose diagnostic differences are expressed as a result of statistical analysis that express minor morphological or genetic differences.

[Mark Smith]

Would anyone care to comment on the fact that there are many examples of two nearly identical looking cichlid species which are clearly shown be two distinct species? Many cichlids in Lake Malawi and Lake Tanganyika have such species in a multiplicity of examples.

On the other hand, Nandopsis tetracanthus, thus far known, has 7 distinct morphological variants, and possibly more once more of Cuba is explored. All 7 variants of N. tetracanthusreside within a 100 mile radius of Havana. What might be in the middle and eastern portions of the island? At least one morphological variant will likely be seen as a distinct species, in my opinion. (Willem - you posted an image years ago of a very deep bodied, thin lower jawed variant of N. tetracanthus, per my inquiry. Might you post it again as a way to contrast it with the nominant variant (or sub-species?) of N. tetracanthus?) One would be hard pressed to see both variants of N. tetracanthusas the same species in light of all the similarly looking, yet distinct species, from Lake Malawi and Lake Tanganyika.

[michi tobler]

Would anyone care to comment on the fact that there are many examples of two nearly identical looking cichlid species which are clearly shown be two distinct species? Many cichlids in Lake Malawi and Lake Tanganyika have such species in a multiplicity of examples.

What holds true for one group does not have to hold true for another. Remember we have a relatively good understanding what mechanisms mediate reproductive isolation even among very closely related and very similar populations of rift valley cichlids. It is that understanding that allows us to discern very similar forms as evolutionarily independent groups. In my opinion, we are far from that in many riverine cichlid groups. Reproductive isolation is not a function of phenotypic divergence. So, I think we should be skeptical if species are delineated simply based on morphological data (taken from a rather low number of specimens). I guess we should not compare apples (Maylandia) to oranges (Australoheros)....
Cheers, m

[Mark Smith]

Thanks Michi - definitely good information to chew on.

[Rico Morgenstern]

So, I think we should be skeptical if species are delineated simply based on morphological data

This is certainly true, every species diagnosis is based only on a random sample out of the entire population/species (BTW this applies also to phylogenetic analyses based on morphological as well as molecular characters). It is probably an overemphasis on the 'diagnosability' component of the Phylogenetic Species Concept, which is used as a justification for establishing species based on smallest phenotypic variation. Although the diagnoses of the Australoheros species described by Ottoni & Costa are very long (due to the many, many species names ), some of the species are distinguished only by single or a few characters, mostly counts (e.g. anal or dorsal soft rays, pterygiophores, rib pairs etc.) known to cover broader ranges in other (also congeneric) species. It needs only to discover slightly more variation within a population of a certain river, and the delimitation of several species will collapse. However, if several independent (and of course suitable) characters are used to delimit species, there is an increasing probability that they prove to be valid. In some instances it is certainly useful to have also large sample sizes to asses if morphometric characters or counts are statistically significant, but in others, such as some species from the Great African Lakes, which differ only in male nuptial coloration, it would be nonsense to erase half the population just to have a large list of examined material.

Of course, every population which is physically isolated from others, does in fact start to go its own evolutionary way. However, as evolution is a continuous process rather than a series of steps we have at least theoretically an infinite number of intermediate states between populations, species etc., so that it is, from an evolutionary point of view, impossible to say were a species 'begins'. All taxonomic categories are in fact artificial and may be not absolutely necessary for understanding evolutionary processes. Nevertheless, the evolution is slow enough to recognize something like species. Also I think we need species for manyfold practical purposes, including such concerning conservation, zoogeography, ecology, ethology etc.. This practical need requires in my view that a species must be something tangible, observable, hence it is useless to have species which are not phenotyoically distinct. From this point of view it would perhaps be the best to adopt something like a 'prudent specieces concept', I think there will never be a technical guidance allowing us to say with certainty "This is a species and this is not".

On the other hand, Nandopsis tetracanthus, thus far known, has 7 distinct morphological variants, and possibly more once more of Cuba is explored. All 7 variants of N. tetracanthusreside within a 100 mile radius of Havana. What might be in the middle and eastern portions of the island? At least one morphological variant will likely be seen as a distinct species, in my opinion.

Well, Mark, these variants of Nandopsis [then Heros] tetracanthus are not as distinct as the drawings imply. None of them is well diagnosed. Heros nigricans, which was regarded as the most distinct form, is based on a single specimen, which may well be somewhat malformed for it shows also some squamation anomalies. Furthermore, the jaw morphology is not very different from other N. tetracanthus, Eigenmann's drawing is inaccurate in this respect. Compare the photo and x-ray of the holotype:

http://research.calacademy.org/redirect ... /index.asp

Even Eigenmann (1903) himself expressed some reservation about the validity of the subspecies (in his 1910 work, he raised all to species level without giving reasons for doing so), and Hubbs (1920) gave further arguments for synonymizing all of Eigenmann's taxa. Here are links to Eigenmann's and Hubbs' works:

http://fisherybulletin.nmfs.noaa.gov/22-1/eigenmann.pdf

http://deepblue.lib.umich.edu/handle/2027.42/56529

I won't deny that N. tetracanthus as currently understood may comprise several species, but these do not necessary correspond to the named subspecies, most of which do not even reflect geographic variation. Furthermore, it is not clear what exactly would be the true N. tetracanthus, as the original description was based only on a drawing and there is no exact type locality known. Likewise, the identity and status of the other two synonyms (Chromis fusco-maculata Guichenot and Acara adspersa Günther), both of which have precedence over Eigenmann's taxa, has to be resolved before applying the available names to taxa if there should be more than one (disregarding the clearly distinct N. ramsdeni). Hence, it would be premature to recognize any of Eigenmann's taxa as valid, and be it only at the subspecies level.

[Ariel Puentes]

Australoheros ykeregua at Soberbio river in Argentina

http://www.youtube.com/watch?v=xdnnFtUdccE

Ariel

[Rico Morgenstern]

Nice to see the new species 'in action', thank you, Ariel!
Its also a good occasion to bring this discussion back from Nandopsis (I know it was me ) to Australoheros. To summarize my current view: I think that there are too much species recognized in the genus, but I feel convinced that the two new ones are valid.

Anyone know the true identity of the fish in the hobby known as A. oblongum?

Hard to say, as there are apparently several species confused under that name. I remember to have read somewhere (perhaps even in this forum, but I don't find the topic yet) that one of the strains originally came from near Sao Paulo. That would mean that it is one of the East Brazilian 'species' already described or yet to be named. The name Australoheros oblongus is certainly wrong, as this species was described from the Upper Tocantins in the State of Goiás. If one or more Australoheros species do occur there (which is by no means excluded), we can hope to get to know the true A. oblongus one day - at least if the responsible ichthyologists choose to consider the previously described taxa more carefully instead of producing one new name after the other.

[cichla]

I think that there are too much species recognized in the genus, but I feel convinced that the two new ones are valid.

Might be true, but I think, it is a curiosity that someone (like Rican et al) challenge the validity of taxa described by an other author, but describing in the very same publication new species which are also very similar to their next related one. Concerning the Australoheros paper by Rican et al (2011) I dont understand the statement (Fig . 11) ''The average number of changes among interspecific pairs described by Říčan and Kullander ... is 98.5, while among intraspecific comparisons it is 20.7. The average for comparisons among the species described by Ottoni ... is 20.5, i.e. corresponding to variation within species of Rican & Kullander. Based on these considerations we believe that the number of described species from the northern Brazilian coastal drainages is a case of excessive splitting and that the species diversity is actually much lower.''
How was it calculated (based on which data)?

we can hope to get to know the true A. oblongus one day - at least if the responsible ichthyologists choose to consider the previously described taxa more carefully instead of producing one new name after the other.

Same as for the species described from the vicinity of Rio. The 'donor' of the type species of A. autochthon 'Lord Stuart' spend his time in Brazil only in Rio. Hence, it is most likely that the specimens are collected there. However, this old available name autochthon is not considered yet.

[michi tobler]

All taxonomic categories are in fact artificial and may be not absolutely necessary for understanding evolutionary processes.

This is not quite correct. A "species" is a real biological entity under the biological species concept. Otherwise, you are correct...
Cheers, m

[Rico Morgenstern]

Thanks Michi, you are of course right. The biological species concept is today quite neglected in ichthyology, although - where applicable - it is still the most convincing one.