STUDYING TARDIGRADES

In your collection of moss of lichens, two basic types of limno-terrestrial tardigrades will be found. Armored specimens are in the Class Heterotardigrade, Order Echiniscoidae (Figure 1; Table 1). Naked specimens are in the Class Eutardigrada, Order Parachela or Apochela (Figure 2; Table 1).

The armored Heterotardigrades will have spotted, pitted, or sculptured dorsal and lateral plates of varying number, size, and shape (Figure 6). Many are red in color. They may have spines of varying length and thickness projecting from the plates (Figure 6). Heterotardigrades have four separate claws on each foot (Figure 8B). The mouthparts (Figure 7B) are often obscured by the cuticular plates. Variations of these features determine genus and species.

The naked Eutardigrades do not have the dorsal plates but a few may exhibit some reticulations, sculpturing, bumps, or even spines (Figures 10, 11). They have a pair of branched claws that vary in size and shape on each leg (Figure 8C-I). Detail of the buccal apparatus is generally visible (Figures 7C-I). Different genera and species may have placoids, teeth, and lamella of varying number and size and exhibit variation in other structures that can be used for identification.