Entozoa
Entozoa is an obsolete taxonomic term that historically referred to a group of parasitic animals that live inside the bodies of other organisms. It was originally used in older classifications to describe a diverse assortment of internal parasites, including parasitic worms and some protozoans. However, the term Entozoa is only broadly descriptive and not based on evolutionary relationships, making it a convenient but scientifically invalid grouping. Coined by Swedish-German naturalist Karl Rudolfi in 1808, the term is considered obsolete and no longer used in modern taxonomy.
Advances in taxonomy and phylogenetics have replaced such groupings with more precise classifications based on evolutionary relationships. Today, these organisms are classified within different kingdoms or phyla, such as Protozoa ; Nematoda ; and Platyhelminthes.
The term Entozoa was initially used at a broad taxonomic level, closer to the rank of a kingdom or a similarly overarching group in older biological classifications. It functioned as a general, non-systematic category for all internal parasites, reflecting the limited understanding of evolutionary relationships in the early 19th century.