Ameletidae – Combmouthed Minnow Mayfly

Author: Stephanie Cox


Kingdom: Animalia

Phylum: Arthropoda

Class: Insecta

Order: Ephemeroptera

Family: Ameletidae

Genus: Ameletus


General Description

The larvae of Ameletus resemble the larvae of minnow-like mayflies such as Baetidae and Siphlonuridae. Ameletus has three pairs of legs; each leg has 3 segments with a single pointed claw. Abdominal gills are leaf shaped, and often stick out laterally. Two widely spaced, short antennae are on top of its head. It has large black compound eyes, with two smaller eye spots. Ameletus also has 3 cerci (tails), although the middle one is often shorter than the other two. The body is S-shaped, making it difficult to lay specimens flat on the dorsal or ventral sides. The most obvious characteristic that distinguishes this family and genus from other minnow-like mayflies is the comb-like maxillae.


Functional feeding group: Collector- gatherer



Ameletidae was found at the following sites:

BC3- Bell Creek


Characteristics for Identification:

1.     Ameletus has short antennae; antennae of Baetidae are long, at least twice as long as the head width.

2.     Ameletus has three cerci, although the middle one may be shorter than the other two.

3.     The maxillae are comb-like, whereas Baetidae and Siphlonuridae lack the comb-like maxillae.


Comb-like maxillae


Lateral view of head, showing short antennae




Lateral view of thorax and abdomen