Atlantic-rainforest
Guides
Phanocerus clavicornis
riffle beetle
Phanocerus clavicornis is a small riffle beetle in the family Elmidae, measuring approximately 3 mm in length. The species exhibits a broad Neotropical distribution, ranging from Texas and the Caribbean through Central America to southeastern Brazil. Populations in Atlantic Rainforest streams demonstrate significant phenotypic plasticity in body size in response to hydraulic conditions, with smaller larvae occurring during periods of greater rainfall. Both larvae and adults are fully aquatic and occupy the same freshwater environments.