pulmonate

Pulmonate refers to a large and diverse group of air-breathing gastropods within the class Gastropoda. Historically, pulmonates were treated as a discrete subclass or order (Pulmonata), but modern classifications treat Pulmonata as an informal grouping rather than a formal taxon because it is not monophyletic. Members are united by their adaptation to breathing air through a pallial lung, a vascularized mantle cavity, rather than by shared gill structures.

The defining feature of pulmonates is the pallial lung, which functions as an air-breathing organ. Air enters the mantle cavity through a small external opening called the pneumostome and can be regulated to minimize water loss. Many pulmonates have a reduced shell or no shell at all (slugs), while others retain a conventional shell as land snails. Although most pulmonates are terrestrial, some lineages are aquatic and have adapted to freshwater environments, often surfacing to breathe air.

Taxonomy and distribution have shifted with advances in phylogenetics. Pulmonates are distributed across a range of habitats worldwide, from moist forests and grasslands to gardens and wetlands. In modern systems, the traditional group is treated as an informal assemblage rather than a single formal clade, with its constituent lineages placed within several larger clades that reflect their varied evolutionary relationships.

Ecology and life history are diverse. Pulmonates largely feed on plant material and detritus, playing important roles in nutrient cycling. Reproduction varies among species; many terrestrial pulmonates are hermaphroditic, while aquatic forms may have separate sexes. Some species are agricultural pests, while others contribute to soil health and ecosystem dynamics.