Is it a mite?

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Common names

seed shrimps, ostracods

Probability of encounter

High, at least in moist products (e.g., mosses, plants with phytotelmata, rainforest litter).

Quarantine importance

No known importance.

Similarity to mites

Small size and obscured structure. Most likely to be confused with a ptychoid oribatid mite (box mites, Mixonomata), but the latter do not have a bivalved carapace. May also be confused with small clams. Another aquatic crustacean group, the clam shrimp (Conchostraca), have an even more clam-like carapace, but a trunk with 10–32 pairs of appendages.

Morphology

Normal adult length: <3 mm in length
Body tagmata: head and reduced trunk covered by bivalved carapace
Eyes: naupliar eye (black spot under carapace hinge in live animals)
Antennae: antennules and antennae
Mouthparts: mandibles; 2 pairs of maxillae
Legs: antennae, mandibular palps and caudal furca function as legs
Respiration: cuticular
Gonopore: between last pair of appendages
Distinguishing features: bivalved carapace

Comments: The bivalved carapace of ostracods is distinctive, and often has dense setae in terrestrial forms. Terrestrial cypridoid ostracods have robust appendages that allow them to plow through the leaf litter. A dorsal anterior eyespot (under joint of valves) is visible in life. Ostracods are normally considered aquatic organisms and would be expected primarily in wet intercepts (e.g., bromeliads); however, some are inhabitants of humus.

Diversity

>7,000 species

References

• Tree of Life Web Project 2002eTree of Life Web Project 2002e:
  Tree of Life Web Project. 2002. Ostracoda. Version 01 January 2002 (temporary). The Tree of Life Web Project, http://tolweb.org/