Paramecium (Ciliophora) is an ideal model organism to study the biogeography of protists. However, many regions of the world, such as Central America, are still neglected in understanding Paramecium diversity. We combined morphological and molecular approaches to identify paramecia isolated from more than 130 samples collected from different waterbodies in several states of Mexico. We found representatives of six Paramecium morphospecies, including the rare species Paramecium jenningsi, and Paramecium putrinum, which is the first report of this species in tropical regions. We also retrieved five species of the Paramecium aurelia complex, and describe one new member of the complex, Paramecium quindecaurelia n. sp., which appears to be a sister species of Paramecium biaurelia. We discuss criteria currently applied for differentiating between sibling species in Paramecium. Additionally, we detected diverse bacterial symbionts in some of the collected ciliates.

中文翻译：

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草履虫的多样性和墨西哥描述的草履虫的新成员

草履虫（Ciliophora）是研究原生生物的生物地理学的理想模式生物。但是，在中美洲等世界许多地区，人们仍然对草履虫的多样性了解不足。我们结合了形态学和分子方法，以鉴定从墨西哥几个州不同水体收集的130多个样品中分离出的草履虫。我们发现6个代表草履虫形态种，包括稀有的物种草履虫jenningsi和草履虫putrinum，这是该物种在热带地区的第一份报告。我们还检索了五种草履虫复合体，并描述了该复合体的一个新成员，草履虫quindecaurelia ñ。sp。，似乎是草履虫双歧杆菌的姐妹种。我们讨论了目前用于区分草履虫的同胞物种的标准。此外，我们在一些收集的纤毛虫中检测到多种细菌共生体。