Home | Is it a mite? Home | Glossary

Isopoda

Common names: slaters, pillbugs, isopods, sowbugs

Probability of encounter: high

Quarantine importance: tramp species.

Similarity to mites: none.

Morphology
Normal adult length: 5-15 mm
Body tagmata: head (1 obvious pair of antennae), thorax (7 pairs of legs), abdomen (5 free segments; 1 pair of biramous uropods)
Eyes: compound lateral
Antennae: antennae with < 10 segments; antennules vestigial
Mouthparts: mandibles without palps; two pairs of maxillae
Legs: 7 thoracic pairs
Respiration: abdominal gills and  pseudotracheae in basal leg segments
Gonopore: first abdominal segment
Distinguishing features: dorsoventrally compressed; one obvious pair of antennae; 7 pairs of legs and 1 pair of uropods

Comments: The isopod body may be dorso-ventrally flattened, but is often dome-like dorsally and some species can curl into a ball. The second pair of antennae (antennules) are vestigial. The thorax has 7 pairs of legs and the abdomen has a single pair of biramous uropods.

 

Diversity: >10,000 species.

 

References

Tree of Life - http://tolweb.org/tree?group=Isopoda&contgroup=Peracarida

Trueman JWH and Dimitriadis S. (1999). Key to families of Australian aquatic Crustacea, in, An Interactive Guide to Australian Aquatic Invertebrates. Windows Edition 2. CSIRO Publishing, Collingwood, Victoria (LucID CD-ROM interactive key).
 
Williams WD. 1980. Australian Freshwater Life: The Invertebrates of Australian Inland Waters. Macmillian: Melbourne