The family Aspredinidae comprises a clade of complex systematic relationships, both from molecular and morphological approaches. In this study, conventional and molecular cytogenetic studies coupled with nucleotide sequencing were performed in 6 Aspredininae species (Amaralia hypsiura, Bunocephalus cf. aloikae, Bunocephalus amaurus, Bunocephalus aff. coracoideus, Bunocephalus verrucosus, and Platystacus cotylephorus) from different locations of the Amazon hydrographic basin. Our results showed highly divergent diploid numbers (2n) among the species, ranging from 49 to 74, including the occurrence of an XX/X0 sex chromosome system. A neighbor-joining phylogram based on the cytochrome c oxidase I (COI) showed that Bunocephalus coracoideus is not a monophyletic clade, but closely related to B. verrucosus. The karyotypic data associated with COI suggest an ancestral karyotype for Aspredinidae with a reduced 2n, composed of bi-armed chromosomes and a trend toward chromosomal fissions resulting in higher diploid number karyotypes, mainly composed of acrocentric chromosomes. Evolutionary relationships were discussed under a phylogenetic context with related species from different Siluriformes families. The karyotype features and chromosomal diversity of Aspredinidae show an amazing differentiation, making this family a remarkable model for investigating the evolutionary dynamics in siluriforms as well as in fish as a whole.

中文翻译：

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Aspredinidae (Teleostei, Siluriformes) 的染色体进化：与相关群体的种内和种间关系的见解

从分子和形态学方法来看，Aspredinidae 科包括一个复杂的系统关系分支。在这项研究中，对来自亚马逊不同水文位置的 6 种 Aspredininae（Amaralia hypsiura、Bunocephalus cf. aloikae、Bunocephalus amaurus、Bunocephalus aff. coracoideus、Bunocephalus verrucosus 和 Platystacus cotylephorus）进行了常规和分子细胞遗传学研究以及核苷酸测序盆地。我们的结果显示物种之间存在高度差异的二倍体数 (2n)，范围从 49 到 74，包括 XX/X0 性染色体系统的出现。基于细胞色素 c 氧化酶 I (COI) 的相邻连接系统图表明，Bunocephalus coracoideus 不是单系进化枝，而是与 B. verrucosus 密切相关。与 COI 相关的核型数据表明 Aspredinidae 的祖先核型具有减少的 2n，由双臂染色体和染色体裂变趋势导致更高的二倍体核型，主要由 acrocentric 染色体组成。进化关系在系统发育背景下与来自不同 Siluriformes 科的相关物种进行了讨论。Aspredinidae 的核型特征和染色体多样性显示出惊人的分化，使该家族成为研究 siluriforms 以及整个鱼类进化动力学的卓越模型。进化关系在系统发育背景下与来自不同 Siluriformes 科的相关物种进行了讨论。Aspredinidae 的核型特征和染色体多样性显示出惊人的分化，使该家族成为研究 siluriforms 以及整个鱼类进化动力学的卓越模型。进化关系在系统发育背景下与来自不同 Siluriformes 科的相关物种进行了讨论。Aspredinidae 的核型特征和染色体多样性显示出惊人的分化，使该家族成为研究 siluriforms 以及整个鱼类进化动力学的卓越模型。