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Benthic Macroinvertebrate Identification

There are so many different types of living organisms, that scientists long ago devised a classification system (by Linnaeus Exit EPA Disclaimer using Latin) to help keep track of how closely related they were. This system is used to name the organisms in a systematic manner. Let's use a mayfly (Ephemerella  inermis), known to fly-fishers as the Pale Morning Dun, as an example of this taxonomic system.

TAXON LATIN NAME / Feature
Kingdom Animalia (Animal, Plant or Fungi - this is an animal)
Phylum Arthropoda (meaning "joint-legged," are invertebrates)
Class Insecta (insects, 6 jointed legs, head, thorax and abdomen)
Order Ephemeroptera (mayfly, ephemeral meaning short-lived)
Family Ephemerellidae
Genus Ephemerella
Species Ephemerlla inermis

Freshwater benthic macroinvertebrates comprise only three of the many animal phyla – Arthopoda, Annelida, and Mollusca.  There is a fourth Phylum,  Platyhelminthes that has the Class Turbellaria (flatworms) which we are not addressing here. Almost all of the freshwater benthic macroinvertebrates you will encounter fall within the taxnomic groups below.

PHYLUM Arthropoda(crustaceans, insects, spiders, and relatives) Annelida (segmented worms) Mollusca (mollusks)
CLASS Malacostraca (crayfish, pill bugs, shrimp, and relatives) Hirudinea (leeches) Gastropoda (gastropods, slugs, and freshwater snails)
Insecta (see Orders below) Oligochaeta (aquatic earthworms) Bivalvia (bivalves, mussels and clams)
ORDER Ephemeroptera (mayflies)
Odonata (dragonflies and damselflies)
Plecoptera (stoneflies)
Hemiptera (true bugs)
Trichoptera (caddisflies)
Lepidoptera (butterflies and moths)
Coleoptera (beetles)
Megaloptera (alderflies, dobsonflies, fishflies)
Neuroptera (spongillaflies)
Diptera (two-winged or true flies)
  Basommatophora (freshwater snails)
Unionoida (freshwater mussels)
Veneroida (asian clam)

Each of the orders above contain many families. For instance, visit our pages on the Trichoptera (caddisfly) families as an example. Each family, especially the insects, can contain dozens of genera and each genera dozens of species, or sometimes just a few species. We can't go into all of that here, but the links we provide wil hopefully get you started. Visit these links from the University of Michigan Museum of ZoologyExit EPA Disclaimer for more information on taxonomy and systematics for Arthropods, Annelids, and Mollusksand more.

The links below can get you started on identifying the more common macroinvertebrates. Visit our page on common freshwater benthic macroinvertebrates to get started.

Biological Indicators | Aquatic Biodiversity | Statistical Primer


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