Riffle-bugs
Guides
Rhagovelia
smaller water striders, riffle bugs
Rhagovelia is a large genus of small aquatic bugs in the family Veliidae, with over 390 described species. Members are distinguished by a swimming fan on the distal tarsomere of the middle leg, an adaptation that enables rapid maneuvering on water surfaces. The genus has colonized lotic freshwater systems and coastal marine environments across the Americas, with additional species in Africa, Asia, and Oceania. Evolutionary origins trace to gene duplications ('geisha' and 'mother-of-geisha') that created this propelling fan structure, allowing exploitation of faster-flowing and more turbulent streams than relatives lacking this adaptation.