Close relatives of the small genera Cualac (one species) and Floridichthys (two species) in the family Cyprinodontidae show sexual differences in chromosome number, with females having 2n = 48 and males having 2n = 47 with a large Y chromosome representing chromosomal fusion. However, karyotypic analysis of both sexes in F. carpio and C. tesselatus revealed the typical cyprinodontid karyotype, with 2n = 48, one normal-sized metacentric to submetacentric chromosome pair, and a graded series of 23 acrocentric or subtelocentric pairs. The phylogenetic pattern suggests that sexually dimorphic karyotypes have arisen independently on two separate occasions in a group that otherwise shows unusually high stability in chromosome morphology.
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1 June 2016
Karyotypes of Cualac tesselatus and Floridichthys carpio: comments on the phylogenetic distribution of multiple sex chromosomes in North American cyprinodontids
Glen E. Collier,
Anthony A. Echelle,
Arcadio Valdéz-González
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The Southwestern Naturalist
Vol. 61 • No. 2
June 2016
Vol. 61 • No. 2
June 2016