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For Insects, Spiders & Their Kin
For the United States & Canada
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Upcoming Events

See Moth submissions from National Moth Week 2023

Photos of insects and people from the 2022 BugGuide gathering in New Mexico, July 20-24

Photos of insects and people from the Spring 2021 gathering in Louisiana, April 28-May 2

Photos of insects and people from the 2019 gathering in Louisiana, July 25-27

Photos of insects and people from the 2018 gathering in Virginia, July 27-29

Photos of insects and people from the 2015 gathering in Wisconsin, July 10-12

Previous events


Order Isopoda - Isopods

woodlice - Porcellio spinicornis Idotea balthica Large Oniscidean - Oniscus asellus Isopod 2 - Porcellionides Porcellionides pruinosus or floria? - Porcellionides Woodlice Sp.  - Porcellio scaber Atlantoscia floridana Larva
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Crustacea (Crustaceans)
Class Malacostraca (Malacostracans)
Superorder Peracarida (Marsupial Crustaceans)
Order Isopoda (Isopods)
Other Common Names
cressbug, pillbug, sowbug, woodlouse, rock slater, roly-poly
Explanation of Names
Isopoda Latreille 1817
>10,200 spp. worldwide(1) (but probably much more, many checklists seem to underestimate the number of recorded species), >1200 in our area; 11 suborders total, 7 represented in North America
2 to >300* mm (*Bathynomus, a deep sea genus)
key to NA taxa to family level (with species keys under construction) in (2)
key to OH spp. in(3)
from deep sea to terrestrial habitats
See Also
Amphipods are usually laterally compressed (although some aquatic isopods can be too) and have 3 sets of uropods
Insects only have six legs; the isopod group with the least number of legs (Gnathiidae) has 10 legs and most isopods have 14 legs
Myriapods have numerous leg pairs and lack the strong tagmosis (formation of distinct "zones" of modified body segments) that occurs in isopods
Print References
Internet References
Coastal Isopods of California (Brusca et al. 2001)
Taxon profile (Brusca 1997)