The subtropical coastal waters of Brazil have been surveyed regarding their hydroid fauna since 1941. However, a comprehensive compilation of all hydroid records with detailed information has not yet been published for these waters. Besides filling this knowledge gap, we provide an updated species list, along with the biogeographic status (native, introduced, or cryptogenic) of each hydroid species for the area between Ilha Comprida municipality and the state of Rio Grande do Sul. We also present the distribution patterns of hydroid morphotypes, a sampling sufficiency analysis, and spatial-temporal progress of their research. The dataset was compiled by conducting a thorough bibliographical survey, accessing data of zoological collections, and performing field surveys with experimental settlement panels. This work provides an update for new hydroid records for a large number of localities within the study area. We listed 27 families, 59 genera, 129 morphotypes, and 95 unique species. Regarding the unique species, ~ 3% were classified as introduced, ~ 2% as native, and ~ 95% as cryptogenic. The 3% of introduced species include the first record of the non-indigenous Podocoryna loyola on natural substrata and new records of this species for São Paulo. The 95 unique species also represent ~ 19% and ~ 52% of the hydroid fauna recorded in South America and Brazil, respectively. Sampling effort is still not sufficient and therefore continuing research on the hydroid fauna is required, especially for the detection of new introduced species.

自1941年以来，已经对巴西亚热带沿海水域的水体动物群进行了调查。但是，尚未发布有关这些水体的所有记录的详尽信息，包括详细信息。除了填补这一知识空白之外，我们还提供了更新的物种清单，以及Ilha Comprida市和南里奥格兰德州之间每种水状物种的生物地理状况（原生，引进或隐源）。我们还介绍了水状形态类型的分布模式，抽样充分性分析及其研究的时空进展。通过进行彻底的书目调查，访问动物学收集的数据以及使用实验性沉降小组进行实地调查来编译数据集。这项工作为研究区域内许多地方的新水压记录提供了更新。我们列出了27个科，59个属，129个形态型和95个独特物种。关于独特物种，约3％被归类为外来物种，约2％被归类为原生物种，约95％被归为隐源物种。3％的引进物种包括非土著的第一记录Podocoryna loyola在自然基质上的生长和该物种在圣保罗的新记录。这95个独特的物种分别占南美和巴西记录的水生动物的19％和52％。采样工作仍然不够，因此需要对水生动物区系进行持续研究，特别是对于新引入物种的检测。