Diagnostic Key

There are two diagnostic keys featured on this site:

Major zooplankton groups: allows identification of zooplankton specimens to major group level.
Copepods: allows identification of copepod specimens to species level.

These diagnostic keys have been designed for the identification of zooplankton specimens to major group level and to species level for the common copepods in the region via an interactive diagnostic feature-based key.

These diagnostic keys contain at their core a Lucid interactive identification key (written in Java as an applet embedded in an .html page), along with associated images and .html pages. Lucid is a software system that has been designed to deploy effective and powerful identification and diagnostic keys. The identification process involves eliminating taxa or other objects according to diagnostic features associated with the specimen being identified. The identification process is supported by images and fact sheets that help to confirm that choices are correct. For more information on Lucid please go to www.lucidcentral.org

How to use the Lucid player

When you open the key, there are four panes.

The left two panes relate to zooplankton diagnostic features and the right two panes relate to zooplankton groups/species (entities) available in the key.

The upper left pane shows a series of diagnostic features you might choose from. These diagnostic features will help you identify your zooplankton specimen and include features such as body shape, colour and size.

The bottom left pane appears blank, but eventually will list the diagnostic features that you have selected in the key. This listing is increased when more diagnostic features are selected.

The upper right pane displays the groups/species that are in your list of possible groups/species in the key.

The bottom right pane initially appears blank, but will display the taxa/species that have been eliminated or removed from the key once you begin selecting features.

How to use the keys

The keys contain a list of zooplankton groups/species and their diagnostic features. The process of identifying your specimen is done by making diagnostic feature selections in the upper left hand pane. You can choose any diagnostic feature you noticed about the specimen, and groups/species which do not have this feature will be eliminated from the list of possible groups/species on the bottom right hand pane.

For example, in the copepod key, choose ‘spine present’ under the 'genital segment' diagnostic feature, and you will be left with a list of copepods that have spines present on their genital segment. A more common feature, such as 'slender body shape', or 'grey colour', will narrow the list of potential copepod species as well, although to a lesser degree.

Keep choosing additional diagnostic features, and the list of possible species will continue to be reduced, until the group/species list is reduced to a short list of possibilities and in most cases, down to a single choice. You can select diagnostic features in any order that you wish. If you are unsure about a particular feature then leave it out and select the features you are more confident with. Each final group/species choice is linked to an image as well as an external .html fact sheet page. Click on the small thumbnail, or .html icon next to the group/species for more detail. You may need to drag the corners of the browser window for the fact sheet to fit your screen. These fact sheets can be printed by selecting the ‘print this page’ option in the top right hand corner of the page.

In addition, within the copepod key an image is attached to each of the diagnostic features in the interactive key's feature list. Clicking on the image will cause a larger version to appear in a separate pop-up box. You may open several at one time for comparison. So for example, within the ‘body shape’ diagnostic feature option there are images of each body shape type such as slender, cigar-shaped, long, short etc.

If you select the wrong diagnostic feature left click to remove it at any time.

Lucid key toolbar

There is a tool bar at the top of the Lucid player.

 Restart button: Reset the key for another identification.

 Open button: Open a key.

 Collapse all button: Collapse all features.

 Open all button: Open all features.

 Find button: Search for a feature or state.

 Subsets button: Subsets are groups of features or entities pre-defined by the author of the key. To choose a subset (if the key’s builder has specified subsets in the key), open the Subsets list by clicking the Subsets button.

  Find best button: Determine which is the best feature to address at any stage during an identification session. In general, a feature that would, on average, cause the list of features remaning to be halved is a good feature to address.

Next best button and  Previous best buttons: Navigate through the features list, if the first feature nominated cannot be addressed.

Prune button: Scan the features in Features Available and remove any redundant features and/or states for the remaining entities. This may be useful to “clean up” the list of features, to make it less likely that a choice will be useless.

 Shortcuts features button: The Shortcuts function is similar to the Best functions in that it may provide a quicker route to an identification. In Shortcuts the key searches for features that, if answered, would provide an immediate shortcut to an identification.

 Differences button: Useful when you have used the key to try to identify a specimen, and at the end several options still remain. To view a list of features that differ between the entities click on the Differences button.

Help button: Troubleshoot answers to a range of questions.

Please note:

• The keys are written with Lucid software. In order to use the keys Java Virtual Machine v1.4.2 or newer must be installed on your computer. This can be downloaded at www.java.com. Apple users will need to download this from the Apple website.

• The first time you use the keys you may get a blank white screen for a few moments while the Lucid key player is loading. This may happen even with a fast internet connection, so please allow a few minutes for the player to load fully. If the player does not load try refreshing the page. We suggest running only one key at a time. 

• Basic knowledge of zooplankton features and terminology is helpful when using these keys. Please see the anatomy page on this website for further information.

• Depending on your experience with zooplankton, you may not be able to confidently select enough character states or diagnostic features to reduce the list of remaining taxa to a reduced list of groups/species. Or it may be possible that your specimen is not avaiable in this version of the key. If this happens we suggest you use the image-based key in this website, or try referring to an alternative reference.