LOGIN

RSS Facebook Twitter YouTube
GLOSSARY       

SEARCHGLOSSARY

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

PROFILESEARCH

Description of Betta mandor

Home Forums Ichthyology Description of Betta mandor

This topic contains 0 replies, has 1 voice, and was last updated by  Amazonas 6 years, 2 months ago.

Viewing 15 posts - 1 through 15 (of 19 total)
  • Author
    Posts
  • #302295

    Arjan
    Participant

    Hi,

     

    I’m currently looking into the Betta foerschi-complex, partly because I’m interested in keeping one of the species at home and for the other part because I see there’s a lot of confusion about the nature of the species included (the picture of the male fish in the description of Betta foerschi on Seriously fish, for instance, is not B. foerschi according to the article in which B. strohi was described.)

    Unfortunately, I still lack the article in which, amongst others, Betta mandor was first described. Does anyone happen to have a digital copy of:

     

    Tan, H. H. and P. K. L. Ng, 2006 – Ichthyological Exploration of Freshwaters 17(2): 97-114 Six new species of fighting fish (Teleostei: Osphronemidae: Betta) from Borneo.

     

    Your help would be greatly appreciated.

    #348454

    Matt
    Keymaster

    That B. strohi paper is one I never got around to translating yet. What do our pics show then Arjan?

    #348456

    Arjan
    Participant

    I’ll translate the article for you, if you’d like. In short, Betta foerschi is higher bodied than Betta strohi. A line drawn from the middle of the caudal peduncle, over the base of the first ray of the pectoral would go way under the eye in foerschi and almost straight trough the eye in strohi.

    #348460

    macrostoma
    Participant

    It’s so difficult to find publications of IEF because they are not free.
    For any help, there is an illustrated key of the genus Betta available in french and in english!

    See: http://www.cil-ibsc.fr/spip.php?article104

    All actually described species are included.
    It cost around 10 € plus the shipping costs, send a mail to Michel dantec ([email protected])

    #348461

    Matt
    Keymaster

    So the photos in our B. foerschi profile are of B. strohi?

    #348462

    Arjan
    Participant

    @matt said:
    So the photos in our B. foerschi profile are of B. strohi?

     

    So it seems, although the fish pictured could well be Betta mandor too. I don’t know the characters on which the separation of mandor from strohi was based.

     

    @macrostoma

     

    Thanks! I’ll contact the author

    #348463

    macrostoma
    Participant

    I’ven’t find these pics of foerschi. Anyone can give me the links?

    I send a small extract of the key for the difference between foerschi and strohi.

    AAAAAAAA.JPG

     

    I think too that this group must be re-examined in the future becaus the description of these two species not clear and not really scientific! There is a lot of confusions!!!!!!!!

    #348465

    Matt
    Keymaster

    The images in question are here.

    #348467

    macrostoma
    Participant

    Thank’s for pics!

    If I use the figure, the fishes look like B. foerschi and not strohi.

    For me with these pictures it appear that it is foerschi

    #348475

    Arjan
    Participant

    I’ve saved two pictures from both species accounts and added a line or two…

     

    One of the pictures in the mandor profile is clearly not a male of Betta mandor. It is too stocky and the line drawn according to the pictures from the key macrostoma posted corresponds with what we’d expect to see in Betta foerschi.From-betta-mandor-profile.jpg

    The picture in the Betta foerschi profile is somewhat less clear. The line passes just below the eye, but the body of the fish seems to be too slender for foerschi. I suspect that the fish pictured is not completely swimming in a vertical plane, but somewhat tilted. I took some measurements. The relative length of the dorsal fin base is 12.7% of the Standard length (according to the description of B. mandor, this measure is between 10,0 and 12,2% in B. rubra and B. foerschi. Accroding to Schaller & Kottelat 1989) the measurement for B. strohi would be a bit more than it is for B. mandor: 12,6-15,8 vs. 12,3-16.7 % SL). Based on that measurement alone, the fish at least is not Betta foerschi, but it could still be either B. mandor  or B. strohi. Betta-foerschi-according-to-profile.JPG

    Tan & Ng 2006 do not give measurements for the relative length of the caudal fin for Betta strohi, but they do differentiate B. mandor from B. foerschi based on this measurement. According to them, TL is 136.7-149.1 % SL for B. mandor vs. 127.2-133.5 % for B. foerschi. Schaller and Kottelat did give this measurement for their B. strohi and it is a bit wider than for B. foerschi; 127.0-141.4. This particular fish has a measure of 126.2%, which is only very slightly below the range given for B. foerschi and B. strohi. We did, however, just conclude that this fish is not B. foerschi. Based on the relatively short caudal, it is not B. mandor either, which can only lead to the conclusion that it is B. strohi.

    #348482

    Colin
    Participant

    For the last few years I have imported all members of the current Betta foerschi complex, from different Asian exporters and different localities. 

    While there are differences in tail shape and tail length between the “species” of strohi, mandor and foerschi – I am not 100% sure that they are individual species and merely just variations in locality. I can fairly easily look at an individual and name it according to the trade name it was imported under but I think that they are commonly mixed up at collection points, exporters and such like along the way. So what has been imported as “mandor” for the last few years could easily actually be “strohi”.

    What I can say for sure is that I have kept and bred individuals of all of these fish and to describe a fish on how stout it is – in my opinion – nonsense.  Especially with a genus which is so prone to obesity. Also, these fish are very long lived and Betta individuals can reach double figures in age… in which case they often look very different from when they were younger.

    None of the photos here show mature fish more than a year or so old!

    Frustrating if you want to know for sure, but that’s Betta keeping…. Just don’t get into the pugnax group!!!!! 😛

    #348484

    macrostoma
    Participant

    I’m totally agree with Colin, it’s really frustrating 😥

    It sure that there are some variations in body shape or fins with age, there also great variation between wild stocks an tank stocks (obesity, diffrence in fins development in dimidiata group…..).
    It’s important and more complicated to use meristics counts to attempt to discriminate the species.
    It’s difficult but it’s important to try to progress in our modest knowledge of these amazing fishes.
    Probably, as I’ve already said, some species in foerschi or pugnax groups must be re-examinated, the limits between them are not very clear…. To be continued….:D

    #348485

    Arjan
    Participant

    I was wondering when Colin would pop up 🙂

     

    After reading the descriptions of B. mandor  and B. strohi critically, I was left with a feeling of something missing. I read your post last night and figured it’d be wise to sleep over things. Now I know what I was missing, together with something that struck me as rather awkward: No explicit reason is mentioned to describe both species. I.e., both articles fail to mention what’s so special about the populations studied that validates the description of a new species, instead of just reporting on new finds of the already described one. The thing that seemed awkward is the source of the holotype of B. mandor: The holotype is mentioned to be from the “aquarium trade”.

    Of course, a trader could be very honest and accurate when giving data on collection localities, but I would always be very careful in case someone were economically dependant on this kind of knowledge.

    Based on the descriptions a simple key can be made which would separate B. foerschi from the other two based on the line from caudal base over pectoral, which would not touch the eye. The others would be separated based on the relative length of the tailfin. Meristic characters all show some degree of overlap.

    We could start playing the Devil’s advocate and state that there’s a single species, with a fairly large distribution and a lot of intraspecific variance. If I interpret Colin’s post well, that’s not far off… Would you concur and question the viability of the three species? It would be nice to have some definitive proof in the form of a few fish from a known locality, showing character states of more than one of the species according to their respective descriptions. I’m not a ‘lumper’ per sé, but cleaning op a taxonomical mess seems pretty appealing at the moment. Wish I had the funds to go over there myself…

    #348495

    Matt
    Keymaster

    Am no expert on this group of fishes but think we should be very careful about measuring physical characters via photographs…

    #348505

    Colin
    Participant

    I think that my main point – and one that emphasises the potential problem with using aquarium trade stock – is that all three of the similar species are on the same trade list at the same time and that it is all too easy for mix ups to be made along the way… e.g. at the catch location, at the collector’s premises in Borneo, at the packing facility, at the unpacking facility in Singapore, at the exporter’s facility in Singapore, at the packing process in Singapore and then eventually here at the trader in europe…. There are a lot of links in the chain to get species confused… 

     

    Sometimes I look at the fish I get and think… hmmm, that strohi looks like the mandor I got last time????? Best I can do is sell them on with the name they were imported under and remind people not to mix them

    In fact, I am ordering fish this week so might be worth ordering a couple pairs of each for a comparison?

Viewing 15 posts - 1 through 15 (of 19 total)

You must be logged in to reply to this topic.