The genera Ophiophragmus and Amphiodia are amphiurids that are considered taxonomically difficult due to their great resemblance, few diagnostic characters and synonymy problems. Our aim is to redescribe the species using scanning electron microscopy and morphometry of diagnostic structures, and to provide new information for the identification of these Ophiuroidea. Five Amphiodia spp. and six Ophiophragmus spp. recorded in Brazil were rigorously redescribed. The descriptions include new diagnostic characters derived from external morphology, arm microstructures and morphometry. We also provided comparative analyses of species with shared characters such as Amphiodia riisei and Amphiodia trychna. The geographic and bathymetric distributions of the studied species were updated, and new records are provided. All the information presented may be used in taxonomic, ecological and phylogenetic studies, helping to fill gaps in the knowledge of the biodiversity, ecology and evolution of these Ophiuroidea. Conclusively, all the tools applied here assisted in the identification of genera and species and could be useful in other taxonomic studies of Echinodermata.

中文翻译：

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Amphiodia 和 Ophiophragmus（Amphiuridae、Ophiuroidea、Echinodermata）的新诊断特征

属麦冬和两栖动物是两栖类动物，由于它们非常相似，很少有诊断特征和同义词问题，因此在分类学上被认为是困难的。我们的目标是使用扫描电子显微镜和诊断结构的形态学重新描述该物种，并为识别这些蛇尾草属提供新的信息。五两栖动物spp. 和六个麦冬spp. 巴西的记录被严格地重新描述。描述包括来自外部形态、手臂微观结构和形态测量的新诊断特征。我们还提供了具有共同特征的物种的比较分析，例如两栖动物和两栖动物. 更新了研究物种的地理和测深分布，并提供了新记录。所提供的所有信息都可用于分类学、生态学和系统发育研究，有助于填补对这些蛇尾草属的生物多样性、生态学和进化知识的空白。最后，这里应用的所有工具都有助于鉴定属和种，并且可能在棘皮动物的其他分类学研究中有用。