Multilung

Multilung is a term used to describe an organism or system that contains more than one functional pulmonary unit. In biology, it is not a formal taxonomic category but a descriptive idea that can apply to organisms with multiple lungs, lungs with substantial lobation, or additional respiratory sacs that contribute to gas exchange. The most common pattern in many vertebrates is two lungs; when more than two distinct respiratory tissues function together, or when lungs are divided into more than two regions, some authors refer to it as multilung arrangements. Developmental anomalies can also produce supernumerary lung tissue, though such cases are rare and typically affect individuals rather than representing a true multilung species.

In nature, multilung-like configurations are seen in various forms, such as subdivided lungs and paired accessory respiratory structures in different lineages, and in some extinct or poorly understood taxa. In medicine and engineering, the term can describe artificial or modular systems designed to provide multiple exchange surfaces within a single device, for example in experimental ventilation technologies or implanted artificial lungs that operate in parallel.

In popular science fiction and speculative biology, multilung is used to imagine organisms with several independent respiratory units, often explored in relation to circulatory and metabolic adaptations.

The term is essentially descriptive, highlighting the presence of multiple gas-exchange surfaces rather than denoting a particular evolutionary lineage.

Etymology: from multi- meaning many, and lung.