02172nas a2200181   4500008004100000022002500041245015000066210006900216260001600285300001200301490000700313520152700320100002301847700002101870700001901891700002501910856005501935       2021                        eng d  a1993-078X, 1993-077100aDerived karyotypes in two elephantfish genera (Hyperopisus and Pollimyrus): lowest chromosome number in the family Mormyridae (Osteoglossiformes)0 aDerived karyotypes in two elephantfish genera Hyperopisus and Po  cOct-08-2021  a345-3540 v153 a<p><jats p="">The African weakly electric elephantfish family Mormyridae comprises 22 genera and almost 230 species. Up-to-date cytogenetic information was available for 17 species representing 14 genera. Here we report chromosome number and morphology in <jats italic="">Hyperopisus bebe</jats> (Lacep&egrave;de, 1803) and <jats italic="">Pollimyrus isidori</jats> (Valenciennes, 1847) collected from the White Nile system in southwestern Ethiopia. Both taxa displayed the diploid chromosome number 2n = 40, but they differed in fundamental numbers: FN = 66 in <jats italic="">H. bebe</jats> and FN = 72 in <jats italic="">P. isidori</jats>; previously the same diploid chromosome number 2n = 40 was reported in an undescribed species of <jats italic="">Pollimyrus</jats> Taverne, 1971 (FN = 42) from the same region. Our results demonstrate that not only pericentric inversions, but fusions also played a substantial role in the evolution of the mormyrid karyotype structure. If the hypothesis that the karyotype structure with 2n = 50&ndash;52 and prevalence of the uni-armed chromosomes close to the ancestral condition for the family Mormyridae is correct, the most derived karyotype structures are found in the <jats italic="">Mormyrus</jats> Linnaeus, 1758 species with 2n = 50 and the highest number of bi-armed elements in their compliments compared to all other mormyrids and in <jats italic="">Pollimyrus isidori</jats> with the highest number of bi-armed elements among the mormyrids with 2n = 40.</jats></p>
1 aSimanovsky, Sergey1 aMedvedev, Dmitry1 aTefera, Fekadu1 aGolubtsov, Alexander  uhttp://dx.doi.org/10.3897/compcytogen.v15.i4.67681