Supplementary Material for: Chromosome Evolution in Dendropsophini (Amphibia, Anura, Hylinae)

Dendropsophini is the most species-rich tribe within Hylidae with 234 described species. Although cytogenetic information is sparse, chromosome numbers and morphology have been considered as an important character system for systematic inferences in this group. Using a diversity of standard and molecular techniques, we describe the previously unknown karyotypes of the genera <i>Xenohyla</i>, <i>Scarthyla</i> and <i>Sphaenorhynchus</i> and provide new information on <i>Dendropsophus</i> and<i> Lysapsus</i>. Our results reveal significant karyotype diversity among Dendropsophini, with diploid chromosome numbers ranging from 2n = 22 in <i>S. goinorum</i>, 2n = 24 in <i>Lysapsus</i>, <i>Scinax</i>, <i>Xenohyla</i>, and almost all species of <i>Sphaenorhynchus</i> and <i>Pseudis</i>, 2n = 26 in <i>S.</i><i>carneus</i>, 2n = 28 in <i>P.</i><i>cardosoi</i>, to 2n = 30 in all known <i>Dendropsophus</i> species. Although nucleolar organizer regions (NORs) and C-banding patterns show a high degree of variability, NOR positions in 2n = 22, 24 and 28 karyotypes and C-banding patterns in <i>Lysapsus</i> and <i>Pseudis</i> are informative cytological markers. Interstitial telomeric sequences reveal a diploid number reduction from 24 to 22 in <i>Scarthyla</i> by a chromosome fusion event. The diploid number of <i>X.</i><i>truncata</i> corroborates the character state of 2n = 30 as a synapomorphy of <i>Dendropsophus</i>.

雨蛙科（Hylidae）内物种丰度最高的类群为雨蛙族（Dendropsophini），目前已描述的物种共计234种。尽管该类群的细胞遗传学信息（cytogenetic information）较为匮乏，但染色体数目与形态始终被视作开展该类群系统学推断的重要性状体系。本研究依托多种常规实验与分子技术，对异耳蟾属（Xenohyla）、刺蟾属（Scarthyla）以及泪蟾属（Sphaenorhynchus）此前未被报道的核型（karyotype）进行了描述，并为雨蛙蟾属（Dendropsophus）与赖萨普斯蟾属（Lysapsus）提供了全新的细胞学数据。研究结果揭示了雨蛙族内显著的核型多样性：其二倍体染色体数目（diploid chromosome numbers）跨度较大，其中刺蟾属（Scarthyla）的S. goinorum为2n=22；赖萨普斯蟾属（Lysapsus）、Scinax属（Scinax）、异耳蟾属（Xenohyla），以及泪蟾属（Sphaenorhynchus）与假蟾属（Pseudis）的几乎所有物种为2n=24；S. carneus为2n=26；P. cardosoi为2n=28；所有已知的雨蛙蟾属（Dendropsophus）物种均为2n=30。尽管核仁组织区（nucleolar organizer regions, NORs）与C-显带（C-banding）模式存在高度变异，但2n=22、24与28核型中的核仁组织区位置，以及赖萨普斯蟾属（Lysapsus）与假蟾属（Pseudis）的C-显带模式，均可作为具备分类学信息价值的细胞学标记。居间端粒序列（interstitial telomeric sequences）分析显示，刺蟾属（Scarthyla）通过染色体融合事件，实现了二倍体染色体数目从2n=24到2n=22的缩减。截形异耳蟾（X. truncata）的二倍体染色体数目验证了“2n=30为雨蛙蟾属（Dendropsophus）的共衍征（synapomorphy）”这一性状状态。