Sand Minnows

Ametropodidae

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Ephemeroptera
Suborder: Pisciforma
Family: Ametropodidae

Pronunciation

How to pronounce Ametropodidae: /ˌæməˌtrɒpəˈdaɪdiː/

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Summary

Ametropodidae is a family of mayflies characterized by their nymphs that thrive in large rivers with silty sand bottoms. They display specific physical traits useful for identification and are integral to their aquatic ecosystems.

Physical Characteristics

Mature nymphs and adults are approximately 15-25mm in body length. The nymphs have a hypognathous posture with a nearly square head in dorsal view. Mouthparts are exposed, and forelegs are short with a spinous pad at the base of the forecoxa. The tarsal claw is slender and possesses 4-5 spinelike denticles.

Identification Tips

Look for the square head shape of nymphs and the exposed mouthparts. The slender tarsal claw with denticles is also a distinguishing feature.

Habitat

Large rivers with silty sand bottoms.

Distribution

Native to the Pacific Northwest, intermountain west of Canada, and upper Colorado Basin, which extends from southwestern Wyoming to northwestern New Mexico.

Diet

Nymphs are collector-filterers, feeding on organic particles carried by the current.

Life Cycle

Ametropodidae are likely univoltine, with adults emerging in spring and early summer. Nymphal development may continue through the following winter.

Reproduction

Adults have been collected from May through July, indicating a seasonal reproductive cycle.

Ecosystem Role

As collector-filterers, they play a role in the nutrient cycling of aquatic ecosystems by processing organic matter.

Evolution

Ametropodidae is a family of mayflies in the order Ephemeroptera, with three described genera: Ametropus, Brevitibia, and Palaeometropus.