Vieja

New cichlid species and taxonomy

Vieja

Postby cichla » Mon Sep 20, 2010 10:47 am

Dear all,
according to this paper (see below) the genus Vieja is gone.
Greetings, IS

McMahan, C. D., A. D. Geheber & K. R. Piller (in press): Molecular Systematics of the Enigmatic Middle American Genus Vieja (Teleostei: Cichlidae). Molecular Phylogenetics and Evolution.

Abstract
The genus Vieja represents a group of heroine cichlids (Teleostei: Cichlidae) distributed on the Atlantic and Pacific slopes of North and Central America from southern Mexico to Panama. Sixteen species of Vieja are presently recognized; however, based on long-standing taxonomic problems, the genus itself appears to be weakly defined. A number of different generic designations have been proposed for members of Vieja, and recent systematic studies of heroine cichlids have not specifically addressed the validity of the grouping and have not included all species in the genus. Therefore, the purpose of this study was to assess the monophyly of the genus Vieja by including all nominal species in the genus using the mitochondrial encoded cytochrome b gene and nuclear S7-1 intron. Results of Maximum Parsimony, Bayesian inference, and topology tests (constraint tree searches and post-burn-in Bayesian filtering) indicate that the genus is not monophyletic as it is currently recognized. The genus Herichthys was recovered as sister to a clade consisting of a number of Vieja species (V. fenestrata,V. guttulata, V. zonata, V. hartwegi, V. bifasciata, V. breidohri, V. argentea, V. regani, V. melanura, V. synspila, and V. maculicauda, as well as Paraneetroplus bulleri). A clade consisting of V. intermedia, V. godmanni, and V. microphthalma was recovered sister to Theraps. Additionally, V. heterospila and V. tuyrensis were recovered outside of Vieja and Herichthys clades. Based on the results of this comprehensive study, we suggest a revised classification of Vieja species.
User avatar
cichla
CichlidRoom Expert
 
Posts: 407
Joined: Sun Jul 02, 2006 11:31 am
Location: Berlin, Deutschland

Re: Vieja

Postby Philippe Burnel » Mon Sep 20, 2010 11:10 am

Do you have the PDF file ?
seems funny....


Philippe
User avatar
Philippe Burnel
CichlidRoom Expert
 
Posts: 953
Joined: Thu Nov 27, 2003 6:54 am
Location: France/ Normandy

Re: Vieja

Postby Nuchal Man » Mon Sep 20, 2010 1:26 pm

I've got it if anyone wants a copy. I'll be in class until 7 pacific time so I'll send it out later tonight. Just PM me your e-mail.

Sam Borstein
Nuchal Man
 
Posts: 139
Joined: Sat Jul 12, 2008 11:45 pm

Re: Vieja

Postby Willem Heijns » Wed Sep 22, 2010 3:36 pm

Yet another phylogenetic tree! :?

Strange enough this one is composed using only cyt-b, a much disputed molecular character. I would have thought (hoped) that new studies would use more characters, but alas...
Still I took the trouble of analysing three trees that have recently been published, which you can find here.

Note the different positions of bocourti and lentiginosus. Funny to notice that using (practically) the same method can still yield such varying results. At the highest level there is some consistency though. :D Two main sisterclades can be distinguished which in turn have Herichthys as their sister taxon. It is the naming of the two clades that will cause most of the confusion (if followed of course).

McMahan et al propose Paraneetroplus for the first one and Theraps for the second, rendering Vieja, Chuco and Paratheraps junior synonyms. There's lumping for you. I have a hard time believing that such species as regani, maculicauda and fenestratus should all belong to the same genus as Paraneetroplus bulleri. The same goes for ufermanni and bocourti being assigned to Theraps.

Another interesting point is that if you go one level below the proposed genera you will find natural groups such as maculicauda. melanura and synspila (Vieja) as well as breidohri, hartwegi, bifasciatus fenestratus, guttulatus and zonatus (Paratheraps). Excluding bocourti/pearsei and ufermanni from the tree also gives a natural group with irregularis, nourissati, lentiginosus and the trio godmani/intermedius/microphthalmus (Theraps). So I guess only Chuco will have to go.

Unless of course there's other trees to follow....... :shock:
Slàinte mhath!

Uilleam
User avatar
Willem Heijns
CichlidRoom Expert
 
Posts: 779
Joined: Wed Jun 22, 2005 4:18 pm
Location: Stiphout, Netherlands

Re: Vieja

Postby Willem Heijns » Wed Sep 22, 2010 5:16 pm

I forgot one more remark. Placing nebuliferus way out of Paraneetroplus as a close relative of sieboldii is beyond me. These aberrant phylogenetic positions really keep me wondering about the value of molecular approaches....
Slàinte mhath!

Uilleam
User avatar
Willem Heijns
CichlidRoom Expert
 
Posts: 779
Joined: Wed Jun 22, 2005 4:18 pm
Location: Stiphout, Netherlands

Re: Vieja

Postby Bojan Dolenc » Wed Dec 01, 2010 5:02 pm

Change in habit, producing change of function, is the main cause of the production of change in living structure. F. Wood Jones (1953) Trends of life
User avatar
Bojan Dolenc
 
Posts: 211
Joined: Thu Oct 16, 2008 7:12 am
Location: Slovenia - Ljubljana

Re: Vieja

Postby Lee Nuttall » Fri Dec 31, 2010 9:16 am

Are there any official developments on this paper, as the reassigments were only suggested? I ask as some people are starting to describe Vieja as Paraneetroplus. Atleast one well respected magazine i know of is officially using Paraneetroplus over Vieja.
Lee Nuttall
 
Posts: 420
Joined: Sun Apr 20, 2008 5:14 pm
Location: South Staffordshire UK

Re: Vieja

Postby cichla » Wed Jan 05, 2011 1:47 am

Dear Lee, Dear all,
in taxonomy everyone is free to publish his own view. Thus, there is no (one and only) official list of valid names.
The major 'problem' is - in this case -, that there are three or four different teams of scientists are currently working independently (and even in a kind of competition) on the systematics and nomenclature of the middle American cichlids. This is why we are miles away from a robust consensus.
Why it is hard to archive a scientific consensus is explained by Ernst Mayr, the 'Darwin of the 20th Century', he wrote in „This is biology“: "Some factors that work against acceptance of new ideas are not strictly scientific. Perhaps one author was disliked or had even offended the current establishment, while another had unexpected success with a subsequently refuted theory because he belonged to a powerful clique".
The question in this case is: should we accept many genera of middle American cichlids, or only a few. There are (at least) two schools of classification: (1) the evolutionary classification and (2) phylogenetic classification. Which school (or clique of scientists) will 'win' the race is still open.
Greetings, IS
User avatar
cichla
CichlidRoom Expert
 
Posts: 407
Joined: Sun Jul 02, 2006 11:31 am
Location: Berlin, Deutschland

Re: Vieja

Postby Lee Nuttall » Wed Jan 05, 2011 9:46 am

Thankyou,

So in short, sit back and wait to see what happens? :)

The reason i brought up the subject is because i noticed a reprint of a old article i contributed to Practical Fish Keeping. The old nomenclature used are re-assigned to the new ones. I'm not sure if i agree, as i haven't adopted the new assigments myself, preferring to use the old excepted (for now) nomenclature. I believe quickly excepting the new names will just confuse, especially readers new to centrals.

Perhaps i'm being stubbon, :lol: but i've found out that editorial with magazines can be a pain. :?

Thanks again,

Lee.
Lee Nuttall
 
Posts: 420
Joined: Sun Apr 20, 2008 5:14 pm
Location: South Staffordshire UK

Re: Vieja

Postby smitty » Fri Jan 07, 2011 1:21 pm

Sounds to me that some are just trying to make there own mark in the hobby. You would think that if one thought that naming was just they would have productive dialogue.
150gal- Dovi's; 3 AC 110 P.Filters; 2 AC 110 P.Heads; Eheim 2217,2260
180gal- Managuense; 3 AC 110 P.Filters; 2 AC 110 P.Heads; Eheim 2217,2260; FX5
210gal- Argta,Bifsct,Fnstrtus,Maculcda,Regani,Syns,Zntus; 4 AC P.Filters; 2 AC P.Hds; Eheim 2250,2262; FX5
User avatar
smitty
 
Posts: 216
Joined: Sun Sep 07, 2008 9:27 am
Location: Yeadon, Pennsylvania

Re: Vieja

Postby michi tobler » Fri Jan 07, 2011 6:07 pm

Hi all,
just a quick comment. While Ingo's remark about competing scientists making things complicated sure had a kernel of truth, I am afraid that the situation isn't that simple. Central American cichlids, particularly the Vieja/Therpas and the "Cryptoheros" s.l. groups, have a quite complicated evolutionary history that has not been easy to elucidate. Scientists are using different methodologies in order to elucidate this evolutionary history (and ideally taxonomy will then reflect the consensus). In simple cases, different methods yield in the same or similar results, which then makes a stable taxonomy fairly easy. However, in the case of Vieja and some other neotropical cichlids, the different approaches have resulted in disparate, sometimes conflicting findings. This doesn't mean one is worse than the other, or one result is correct or not; it simply means that further work is needed to conclusively resolve the evolutionary history of the group. At this point, the results of the different studies are all valid alternative hypotheses. Only further research can show, which of them will be falsified and which verified. This may be unsatisfactory, but it is the normal course of the scientific endeavor. So, I am actually quite interested in each and every new phylogenetic tree that comes out, because it allows us to refine our knowledge, hopefully to the point where we have a comprehensive understanding about our fish. I find it immensely intriguing to see completely unexpected placements of taxa in a tree. It doesn't frustrate me, but it forces me to think about how evolution might have driven the diversification of species. Formerly, I thought the scatter of cichlids previously assigned to Archocentrus (now Amatitlania, Crypoheros, etc.) and Herotilapia must have been due to poor resolution of our methods. After similar pattern have come up in repeated studies, I think it may not be far fetched that some species that appear very similar may have evolved convergently, which certainly would not be unprecedented in the family. Obviously, I hold my breath and I am prepared to be convinced otherwise.
The reason why some of the authors refrain from making taxonomic conclusion is because they recognize the gap in knowledge and the need for additional work. One of the core concerns of biological nomenclature is stability, so it makes sense to hold off on continuous name changes until the issue is addressed with adequate data. After all, I would also disagree with the statement that taxonomy is simply a matter of opinion. At least to the second to the last step (resolving relationships), it should be a matter of data and evidence. At the last step, when people have to decide where to draw the line, it may be a matter of opinion as valid groups can be assembled in multiple ways. But we are clearly not at that stage with the Vieja.
Cheers, m
Humans are not the pinnacle of evolutionary progress but only an aberrant side branch of fish evolution - Moyle

Website
User avatar
michi tobler
CichlidRoom Expert
 
Posts: 431
Joined: Thu Nov 27, 2003 3:15 pm
Location: College Station, TX

Re: Vieja

Postby cichla » Sun Jan 09, 2011 8:00 am

Thank you, Michi, for pointing out this important aspect. Well, I agree 100% that taxonomy should not be a matter of personal opinion, but should be based on data and evidence.
However, the classification and naming is and will be subjective. In the case of the middle American cichlids it is cumulating to the question ''how many genera of middle American Cichlids are there (should be recognized)?'' In other words, even we would have a robust phylogenetic tree of this particular group of fish, where should we chop the tree.

I think the 'problem' is - in this case – that there are multiple clashes are involved. Those which prevent a robust nomenclature are: (1) different teams, (2) morphological versus molecular analysis, (3) evolutionary versus phylogenetic classification, (3) Linnean versus phylo code and etc....

All these things can not be settled instantly, but depends on a scientific process, which needs its time. This is why I believe that it take another half of a decade before we obtain a robust nomenclature.
Thus, I concur with
Lee wrote:So in short, sit back and wait to see what happens
;-)

Greetings, IS
User avatar
cichla
CichlidRoom Expert
 
Posts: 407
Joined: Sun Jul 02, 2006 11:31 am
Location: Berlin, Deutschland

Re: Vieja

Postby Paulo José Alves » Tue Jan 11, 2011 7:38 am

Hi

The simple truth is that the concepts of species, genus and their relationships are not completely explained and defined in an iron clad contract. The adition of the genetic analisys gave a significant contribution but in the end it didn´t help in putting all this question in black and white terms and diluting all doubts. What we see repetedly is that the new nomenclatures are replaced in time, annoyingly to the fish keepers, which means that they are flawed and of course because the other taxonomists don´t agree with them. So a matter of opinion is indeed in the end what rules taxonomy which seems to be a not very cientific science...

All The Best
Paulo José Alves
All The Best
Paulo José
Paulo José Alves
 
Posts: 266
Joined: Wed Feb 02, 2005 7:43 am
Location: Barreiro, Portugal

Re: Vieja

Postby Bas Pels » Tue Jan 11, 2011 8:15 am

Paulo José Alves wrote: So a matter of opinion is indeed in the end what rules taxonomy which seems to be a not very cientific science...


Personally, I think this is said a bit to firmly

As Michy explained above, there is a matter of appreciation in taxonomy, but only in the very end.

differences between museumsamples are either measured correctly, or not. OK, once the teeth of cichlids were considered as very important, now we see them as very recent adaptations, and thus not important for finding relations between species

What my tree looks like is not a matter of appreciation, in the end there can conly be 1 tree

Only then comes the part of opinions.

But, this isonly how I see matters :)
Bas Pels
 
Posts: 2078
Joined: Fri Mar 03, 2006 10:17 am
Location: Nijmegen - the Netherlands


Return to Taxonomy

Who is online

Users browsing this forum: No registered users and 0 guests