Saduria entomon

Saduria entomon is a benthic isopod crustacean of the family Chaetiliidae.^[2][3] It is distributed along the coasts of the Arctic Ocean and of the northern Pacific Ocean. It is also found in the brackish Baltic Sea, where it is considered a glacial relict.^[4] Moreover, it is present in a number of North European lakes, including Ladoga, Vänern and Vättern. It has been introduced into the Black Sea.^[5]

Saduria entomon
Dead Saduria entomon washed up on the beach
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Isopoda
Family:	Chaetiliidae
Genus:	Saduria
Species:	S. entomon
Binomial name
Saduria entomon (Linnaeus, 1758) [2][3]
Synonyms
Oniscus entomon Linnaeus, 1758 Mesidotea entomon (Linnaeus, 1758)[3]

Biology

Saduria entomon is one of the largest crustaceans in the Baltic Sea. The largest ones are found in the depths of the Gulf of Bothnia,^[6] reaching a maximum length of nearly 9 cm (4 in).^[4] S. entomon are sexually dimorphic, with males growing larger and maturing at larger sizes than females.^[7] Most individuals die after reproduction, and the species might be functionally semelparous, but it is probably capable of iteroparity. Its lifespan is 3 years, possibly much longer.^[7]

Saduria entomon is a predator that feeds on other benthic animals, such as Monoporeia affinis. It is also a scavenger and a cannibal.^[4]