Cedrola Franciane, Senra Marcus Vinicius Xavier, Rossi Mariana Fonseca, Fregulia Priscila, D'Agosto Marta, Dias Roberto Júnio Pedroso
Laboratório de Protozoologia, Programa de Pós-graduação em Comportamento e Biologia Animal, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora, Juiz de Fora, Brazil.
Instituto de Recursos Naturais Renováveis, Universidade Federal de Itajubá, Itajubá, Brazil.
Front Microbiol. 2020 Jan 15;10:2967. doi: 10.3389/fmicb.2019.02967. eCollection 2019.
The gastrointestinal tracts of most herbivorous mammals are colonized by symbiotic ciliates of the subclass Trichostomatia, which form a well-supported monophyletic group, currently composed by ∼1,000 species, 129 genera, and 21 families, distributed into three orders, Entodiniomorphida, Macropodiniida, and Vestibuliferida. In recent years, trichostomatid ciliates have been playing a part in many relevant functional studies, such as those focusing in host feeding efficiency optimization and those investigating their role in the gastrointestinal methanogenesis, as many trichostomatids are known to establish endosymbiotic associations with methanogenic Archaea. However, the systematics of trichostomatids presents many inconsistencies. Here, we stress the importance of more taxonomic works, to improve classification schemes of this group of organisms, preparing the ground to proper development of such relevant applied works. We will present a historical review of the systematics of the subclass Trichostomatia highlighting taxonomic problems and inconsistencies. Further on, we will discuss possible solutions to these issues and propose future directions to leverage our comprehension about taxonomy and evolution of these symbiotic microeukaryotes.
大多数食草哺乳动物的胃肠道中栖息着毛口亚纲的共生纤毛虫，它们构成了一个有充分支持的单系类群，目前由约1000个物种、129个属和21个科组成，分为三个目，即内毛目、袋鼠目和前庭亚目。近年来，毛口目纤毛虫在许多相关功能研究中发挥了作用，比如那些关注宿主进食效率优化的研究以及那些探究它们在胃肠道甲烷生成中作用的研究，因为许多毛口目纤毛虫已知与产甲烷古菌建立内共生关系。然而，毛口目纤毛虫的系统分类存在许多不一致之处。在这里，我们强调更多分类学工作的重要性，以改进这类生物的分类方案，为这类相关应用工作的合理开展奠定基础。我们将对毛口亚纲的系统分类进行历史回顾，突出分类学问题和不一致之处。进一步地，我们将讨论这些问题的可能解决方案，并提出未来的方向，以增进我们对这些共生微真核生物的分类学和进化的理解。
