Membraanidel

Membraanidel refers to membranelle-like structures described in some non-English sources for certain ciliates and related protists. In modern English-language protozoology the term membranelle is the standard expression, and membranidel is often considered a variant or historical usage. A membranelle is a cytoplasmic assembly of cilia that forms part of the organism’s oral apparatus and typically functions in feeding by generating water currents and directing particles toward the cell mouth.

In ciliates, membranelles are usually organized as rows or tufts of cilia that act as a functional unit. They can be classified as adoral membranelles, located near the mouth opening, and paroral membranelles, along the edge of the oral region. The coordinated beating of membranelles helps produce a feeding current and facilitates the ingestion of bacteria and other small prey. The precise arrangement varies among taxa; in some groups membranelles are prominent features of the oral apparatus, while in others they are less conspicuous or are replaced by other structures such as undulating membranes.

Taxonomic status: membranelles are descriptive features rather than a named taxonomic group. When the term membranidel is used, it generally refers to membranelle-like structures and is usually clarified by specifying the particular components of the oral ciliature being described.

See also: ciliates, protozoa, membranelle, oral apparatus.