Isonychiidae

Definition

A family of brushlegged mayflies (order Ephemeroptera) containing the single genus Isonychia, distinguished by adults with dense, plumose forelegs used for filtering particles from the water column and larvae adapted to clinging in lotic habitats.

Etymology

Example

Larvae of Isonychiidae possess enlarged, fringed forelegs with rows of setae that function as passive filtration devices, allowing them to exploit suspended organic matter in fast-flowing streams—a convergence with some filter-feeding caddisfly and black fly larvae.

Related Terms

• Isonychia
• Ephemeroptera
• Siphlonuridae
• brushlegged mayfly
• filter-feeding
• lotic

Usage Notes

A small, phylogenetically isolated family within the pisciform mayfly grade; sometimes treated as subfamily Isonychiinae within Siphlonuridae in older classifications. The familial rank is now widely accepted based on larval and adult autapomorphies. Not to be confused with similarly named taxa in other insect orders.