Ameletus was previously included among genera of the Siphlonuridae, but is now the only genus in the family Ameletidae. There are 34 known species in North America, most from west of the Rocky Mountains. Larvae are fusiform or streamlined in body shape, making them strong swimmers and clingers. They are collector-gatherers or scraper-grazers, feeding on fine detritus and diatoms. They tend to be found in cold, fast-flowing mountain streams, especially along edges, undercut banks, and in root masses. The family can often be confused with Isonychiidae or Baetidae, but can be distinguished by its maxillae, each with a row of golden pectinate spines.
Upper Midwest: up to 0
Southeast: up to 2.1
0 = least tolerant, 10 = most tolerant
Collector / Gatherer
Scraper / Grazer
Single Tarsal Claw
Usually 3 Tails
Notched Upper Lip
Pectinate Spines On Maxillae
+ Expanded Character List
Wings developing in wing pads. Mouthparts suitable for chewing. Gills present on tops and sides of abdomen. Segmented legs present. One tarsal claw per leg. Usually with 3 tails (sometimes 2).
Body not flat. Labrum without notched distal margin and maxillae each with row of golden pectinate spines. Tusks absent. Antennae shorter than twice width of head. Thoracicnotum not turtle-shell-shaped. Abdominal terga usually without paired tubercles. Abdominal segment 2 with gills similar to those on other segments but NOT operculate/semioperculate; with single lamellae more or less oval and with sclerotized band along lateral margin and usually with a similar sclerotized band on or near mesal margin; gills usually not fringed; never ending in filaments or points. Forelegs without long hairs. Tibiae and tarsi not bowed; claws usually not long and slender. Claws of all legs similar, usually sharply pointed, variable in length. Three tails of about equal length.
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