LIVEBEARERS T Phallichthys tico - - a dainty new ... - Aqualog

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Aqualognews NUMBER 94 18 The Bayreuth specimens produced by Walter F. Ranninger in 1968 were first exhibited at a fish club show and auction as the ‘Bayreuth cross’. A little under a year later, in August 1969, the new fish was presented to the general public at the Second International Competition and Exhibition staged in Mönchengladbach, followed, another year later, by the same variety being produced by Karl W. Hamel from Bensheim in southern Hesse. In tips afforded to potential breeders of this fish, which can contain either red or yellow coloration, in addition to black, it is recommended never to cross two high-finned fish, but, rather, to choose a high-finned female and a normal-finned male. This reportedly results in more high-finned offspring than if the cross were reversed, i.e. a high-finned male and a normal-finned female. I have encountered a similar situation several times over the years, with hybrids produced between two related species sometimes ending up with more characteristics from their mother than their father, e.g. higher number of body spots in Limia vittata x L. melanogaster hybrids in which the mother was a L. vittata, and more body stripes when the mother was a L. melanogaster. The Simpson fin of this specimen is very beautifully developed. While, at first sight, this seems a little confusing – since both parents contribute equally in terms of chromosomes – there could be an explanation. Such a phenomenon is well known in biology and is referred to as cytoplasmic, extra-nuclear or maternal inheritance, i.e. inheritance of maternal characteristics which are not directly linked to the genes found in chromosomes. Because (in the vast majority of cases) sperm contain no cytoplasm, or very little, but eggs contain a lot, including genes not located on the chromosomes but in other structures such as mitochondria (involved in energy production), mothers may end up contributing more genetic material overall to their offspring than fathers. This can result in offspring inheriting and exhibiting a larger number of characteristics (not necessarily physical, but biochemical as well) from their mother than their father. This is not to say that the situation observed in Bayreuth swords is down to cytoplasmic inheritance…but it could, at least, have a bearing on the reported results. Will we ever know?
Aqualognews NUMBER 94 19 RARITIES In brief: Zenarchopterus dunckeri by Roman Neunkirchen Zenarchopterus cf. dunckeri from Taiwan. Photo: Frank Schäfer The halfbeak genus Zenarchopterus contains 20 species which all occur along the Pacific coast of tropical Asia. Maximum length is around 15 cm, with only a few species growing somewhat longer and all usually remaining significantly smaller. The species look extraordinarily similar to one another and the only way they can be identified with any certainty is on the basis of the externally visible sex organ in adult males, in which the posterior part of the anal fin is modified into a copulatory organ termed the andropodium. Only one species, Z. quadrimaculatus,exhibits any body patterning, while all the others are silver in color. Aquarium Glaser has now imported a Zenarchopterus from Taiwan, thought to perhaps be Z. dunckeri. Zenarchopterus are fascinating brackish-water fishes (salt content 5-15 g/l.) that always swim near the water’s surface. In the wild they feed on insects that fall into the water, while in the aquarium they will also take flake food very readily. Zenarchopterus are very peaceful among themselves and towards other fishes, but are easily frightened and hence should not be kept in combination with "outgoing" species. All species are probably egg-layers with internal fertilization, but as yet no detailed breeding reports are available.
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LIVEBEARERS T Phallichthys tico - - a dainty new ... - Aqualog

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