Lentelmis

Lentelmis is a genus of aquatic beetles in the family Elmidae, commonly known as riffle beetles. Species in this genus are typically small and flattened, adapted to life in fast-flowing fresh water. Both adults and larvae are aquatic and respire using a plastron or other cuticular structures, allowing them to inhabit under stones and submerged vegetation in clean, well-oxygenated streams and rivers. They are primarily detritivores and grazers, feeding on biofilm, algae, and micro-organisms on submerged substrates.

Taxonomy and naming: The genus is placed within Elmidae, a family characterized by slender bodies and tarsal adaptations for clinging to submerged surfaces. The exact number of described species within Lentelmis is variable as taxonomic revisions occur; species identification typically relies on examination of elytral sculpturing and male genitalia, as well as other morphological features.

Distribution and habitat: Lentelmis species are found in freshwater ecosystems across several biogeographic regions, with many taxa described from tropical and subtropical zones. They prefer clean water and are often used as indicators of aquatic ecosystem health.

Ecology and biology: Life cycle comprises egg, larval, and pupal stages that develop entirely underwater; adults may be active on submerged substrates during multiple seasons. They contribute to the turnover of microbial biofilms and serve as prey for fishes and invertebrates.

Importance: In ecological studies, Elmidae, including Lentelmis, are used as bioindicators of water quality due to their sensitivity to pollution and changes in flow regimes. Conservation concerns arise where stream habitats are degraded.