Jassa marmorata is a species of tube-building amphipod. It is native to the northeast Atlantic Ocean but has been introduced into northeast Asia. J. marmorata are greyish in colour with reddish brown markings. The can grow to a length of up to 10 millimetres (0.39 in). They are generally found in fouling communities and intertidal areas where they build tubes of detritus and algae fragments using silky mucus secretions.[1][2][3] They are remarkable for having two distinct morphs of males with two different mating strategies. The 'major' morphs are fighter males, while the 'minor' morphs are sneaker males.[4]
^Mario de Kluijver; Sarita Ingalsuo. "Jassa marmorata". Macrobenthos of the North Sea – Crustacea. Marine Species Identification Portal. Retrieved February 6, 2012.
^Jocelyn Nelson. "Jassa marmorata Holmes, 1905". Marine Biodiversity of British Columbia, LifeDesks. Archived from the original on April 15, 2013. Retrieved February 6, 2012.