This study provides new insight into the chromosomal diversification in Loricariinae. We analyzed nine species from different Brazilian hydrographic basins, using conventional and molecular cytogenetic methods, aiming to understand the karyotypic diversification, and contribute with cytotaxonomic markers in this group considered one of the most diverse of Loricariidae. Our results evidenced a high karyotypic variability in diploid number (2n) ranging from 2n = 54 (Loricariichthys platymetopon and Loricariichthys anus), 2n = 60 (Rineloricaria reisi and Rineloricaria parva), 2n = 62 (Proloricaria prolixa), 2n = 64 (Loricaria cataphracta complex species), 2n = 66 (Sturisoma barbatum), and 2n = 68 (Pyxiloricaria menezesi). Different patterns of 18S and 5S ribosomal DNA (rDNA) were also identified, while slight divergences in heterochromatin distribution were observed. This high variability is probably related with independent events of Robertsonian translocations, pericentric inversions, and different mechanisms of rDNA sites dispersion (nonreciprocal translocation and transposable element [TEs] co-localization). In addition, our study provides a set of efficient chromosomal markers for the characterization of all analyzed species, and certainly, in future analyzes, will contribute as a useful cytotaxonomic tool in groups where the traditional taxonomy based on morphological data are not sufficient to clarify their relationship.

中文翻译：

---

揭露重点在硬皮瘤，南美白对虾，南美白对虾，Proloricaria，Pyxiloricaria和Rineloricaria的Cat鱼（Loricariinae）的核型演变和细胞分类学

这项研究提供了对Loricariinae染色体多样化的新见解。我们使用常规和分子细胞遗传学方法分析了来自不同巴西水文盆地的九种物种，目的是了解核型多样化，并与该组中被认为是最广泛的蝗科之一的细胞分类标记有关。我们的研究结果表明二倍体数（2 n）的染色体核型变异性较高，范围从2 n  = 54（Loricariichthys platymetopon和Loricariichthys anus），2 n  = 60（Rineloricaria reisi和Rineloricaria parva），2 n  = 62（Proloricaria prolixa），2n  = 64  （白头茅（Loricaria cataphracta）复杂种），2 n =  66 （巴氏Sturisoma barbatum）和2 n = 68（Pyxiloricaria menezesi）。18S和5S的不同样式还鉴定了核糖体DNA（rDNA），同时观察到异染色质分布略有差异。这种高变异性可能与罗伯逊易位，周向倒置和rDNA位点分散的不同机制（不可逆易位和转座因子[TEs]共同定位）的独立事件有关。此外，我们的研究为表征所有被分析物种提供了一套有效的染色体标记，并且在将来的分析中，肯定会作为有用的细胞分类工具，在基于形态学数据的传统分类法不足以阐明其特征的人群中关系。