Benthic Key authorship

Introducing a new and exciting tool for the identification of benthic macroinvertebrates in North America.

The most widely used type of classification system is the dichotomous key. A dichotomous key consists of a series of choices that lead the user to the correct name of a given item. "Dichotomous" means "divided into two parts". Therefore, dichotomous keys always give two choices in each step. Tradition taxonomic identification keys generally require more than a basic understanding and training in character and characteristic identification. For example, if you were unsure of one characteristic and chose the wrong answer at a single step in the dichotomous key, you would not able to reach the proper identification without going back to find the error in your key pathway.

The CRI BMI Interactive key is a multi-step diagnostic key that allows new learners and users to be able to iteratively add or eliminate only the characteristics that they can positively attribute to their specimen. This process is also aided in most cases by multimedia images that allow students to see where the characteristics are located and also compile photographs to demonstrate what these characteristics look like in real life. The multi-step key progressively eliminates taxa that do not match the chosen features until only one or a few remain, and then multimedia fact sheets and images provide further information for making a final and positive identification.

Click on the key below to access the CRI BMI Interactive Key.

Benthic Key


If you are having troubles opening the key, click here to check if your system has the approriate version of Java to run the key. The key (which uses the Lucid software) requires the Sun Java Runtime Environment (JRE) version 1.4.2 or greater.

Brief Key Instructions

Key Instructions #1

Key Instructions #2