Bug FAQBlunt-tailed Isopod
Idotea urotoma · Order: Isopoda · Family: Idoteidae
The blunt-tailed isopod matches the colour of the seaweed or seagrass it lives on, from yellow-gold to reddish brown or black. It inhabits low intertidal and shallow subtidal zones along the Pacific coast from Washington’s Puget Sound to Baja California. It is gonochoric, with males and females mating before or sometimes during molting.
Source: Wikipedia
How to recognize it
The rear edge of the tail forms a broad triangle where the sides meet without a central point.
Source: Wikipedia
Size
Its body colour matches the seaweed or seagrass it lives on, ranging from yellow-gold to reddish brown or black.
Source: Wikipedia
Life cycle
The species is gonochoric, with males and females mating before or sometimes during molting.
Source: Wikipedia
Where it comes from
Its native range includes the Pacific coast of the United States from Washington to Mexico.
Source: Wikipedia
Where it is found in the US
Recorded in 4 of 51 states and DC. Most records: California, Washington, Alaska, Oregon.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in United States; native in Canada. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Same family (Idoteidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Idotea_urotoma
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-26 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-26.