A cryptic species of Dicrossus?

19. April 2016

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Dicrossus filamentosus, the checkerboard cichlid, is a permanent guest in our fishhouse. The beautiful dwarf cichlids make gorgeous aquarium inhabitants.

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Last week we obtained a shipment of large specimens from Manaus, almost exclusively males. We decided to photograph them due to their brilliant coloration.

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During selecting the models for the photo aquarium two unusual facts became obvious. First: one of the males was extraordinary deep bodied. And twice: there was no female in the shipment that showed the typical red ventral fins of sexually active females.

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Instead the selected female showed two features that were also found in the unusual deep bodied male: the black marks along the side were almost quadratic (instead of rectangular) and there was a small black spot on the basis of the ventral fins (lacking in “normal” checkerboards).

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Of course this can be pure chance. But it is also possible that the unusual checkerboards represent a hidden, so-called cryptic, different species. Since genetic analyses (DNA-analyses) have become so cheap, it has been found that cryptic species, which can be hardly told apart from well known species by external features, but which are totally different from a genetic point of view, are comparatively common.

For our customers: the Dicrossus filamentosus we currently have in stock have code 668002 (sm) and 668005 (lg-xlg) on our stocklist. Please note that we exclusively supply the wholesale trade.

Text & photos: Frank Schäfer