Cylloepus

Cylloepus can be distinguished from other elmid genera by characteristics of the adult morphology typical of the tribe Elmini. Specific diagnostic features for the genus require examination of adult specimens, particularly details of the pronotum, elytral sculpture, and male genitalia. The genus is most readily separated from similar riffle beetle genera through a combination of body form and antennal structure.

Species in this genus inhabit lotic freshwater environments, specifically riffle zones of streams and rivers. These beetles require well-oxygenated, flowing water and are typically found clinging to submerged rocks, woody debris, and other stable substrates in current.

Documented from North America (including the United States), the Caribbean (Haiti), and South America (extensively recorded across Colombia including departments of Amazonas, Antioquia, Boyacá, Caldas, Caquetá, Casanare, Cauca, Cesar, Chocó, Córdoba, Huila, La Guajira, Magdalena, Meta, Nariño, Norte de Santander, Putumayo, Quindío, Risaralda, Santander, Tolima, Valle del Cauca, and Vichada).

Adults are fully aquatic and remain submerged, using plastron respiration to extract oxygen from water. They are clingers, maintaining position in flowing water by grasping substrate with their legs.

As riffle beetles, members of this genus contribute to nutrient cycling in freshwater ecosystems through processing of allochthonous organic matter and serve as prey for larger aquatic organisms.

• ElmisBoth genera belong to tribe Elmini and share similar aquatic habitat preferences; Cylloepus is distinguished by specific morphological characters of the pronotum and male genitalia
• MacronychusAnother elmid genus in tribe Elmini with overlapping distribution; separation requires detailed examination of body proportions and antennal structure

• riffle beetle
• aquatic insect
• Elmidae
• lotic
• freshwater

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life