Western Sea Roach
Ligia occidentalis
Description 7
This isopod is commonly encountered on rocks and jetties all over the Bay Area, both inside the bay and on the outer coast. Most are relatively small, between 1-2 cm, but they can grow up to 4 cm beasts. Garthwaite and Lawson report that the species was originally described from specimens collected along the Sacramento River, so it may still extend that far inland.
The only similar species in size and habitat is L. pallasii, which has eyes that are separated by a distance equal to about twice the width of one eye, whereas L. occidentalis has more closely-set eyes that are separated by about a single eye width. L. pallasii is much less common in the Bay Area (though it becomes more common further north on the eastern Pacific coast), and will probably only be encountered in protected microhabitats on the outer coast, like sea caves, while L. occidentalis can be found almost anywhere with salt water and rocks.
Sources and Credits
- no rights reserved, uploaded by Scott Loarie
- (c) Damon Tighe, some rights reserved (CC BY-NC), uploaded by Damon Tighe
- no rights reserved, http://www.flickr.com/photos/55368994@N06/12869873524/
- (c) Don Loarie, some rights reserved (CC BY), https://www.flickr.com/photos/loarie/15576358503/
- (c) Don Loarie, some rights reserved (CC BY), https://www.flickr.com/photos/loarie/16008701348/
- (c) Don Loarie, some rights reserved (CC BY), https://www.flickr.com/photos/loarie/15576359793/
- (c) Ken-ichi Ueda, some rights reserved (CC BY-SA)
More Info
iNat Map
| Number of articles in flagellum of antenna | >10 |
|---|---|
| Distance between eyes | one eye length |
| Uropod length | <2/3 the body length |
| Relative position of exopod and endopod insertion on peduncle | Both exopod and endopod inserted distally |
| Habitat | littoral |
| Status | Pacific Coast Endemic |
| Frequency | common |
| Capable of rolling up? | no |
| Present in noca? | yes |
| Present in soca? | yes |
