Spirotrichs

Spirotrichs are a group of ciliated protozoa, belonging to the phylum Ciliophora. These single-celled organisms are characterized by their distinctive arrangement of cilia, which form complex structures called membranelles in the oral region. These membranelles are typically spirally arranged and are used for both filter-feeding and locomotion. Spirotrichs are found in a wide range of aquatic environments, including freshwater, marine, and brackish waters, as well as in moist soil.

Morphologically, spirotrichs exhibit a diverse range of forms, but generally possess a well-defined anterior end where the elaborate oral apparatus is located. The body is often covered in somatic cilia, which may be arranged in rows. They are heterotrophic, feeding on bacteria, algae, and smaller protozoa. Reproduction in spirotrichs is primarily asexual, through binary fission. Sexual reproduction, known as conjugation, also occurs in some species, involving the exchange of genetic material.

Notable genera within the spirotrichs include Stentor, known for its trumpet-like shape and the ability to retract its body, and Spirostomum, which is elongated and often found in freshwater habitats. The study of spirotrichs contributes to our understanding of ciliate evolution and the diversity of microscopic life in aquatic ecosystems. Their complex oral structures make them a subject of interest in cell biology and protistology.