''Osedax roseus'' is a species of bathypelagic

polychaete worm Polychaeta () is a paraphyletic class of generally marine annelid worms, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are mad ...

that lives at abyssal depths and is able to sustain itself on the bones of dead

whale Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...

s. The species is found in the North East Pacific.

Behavior

When a whale dies, its carcass falls to the seabed. Here it provides a feast for many deep-sea invertebrates. Worms such as ''Osedax roseus'' make use of the bones when only the skeleton remains. The worms produce a branching network of "roots" which house

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

bacteria which enable the worms to utilise the bones' nutrient content. This worm was first described from a whale carcase that fell to the seabed in

Monterey Bay, California Monterey Bay is a bay of the Pacific Ocean located on the coast of the U.S. state of California, south of the San Francisco Bay Area and its major city at the south of the bay, San Jose. San Francisco itself is further north along the coast, by a ...

, settling at a depth of . Time lapse photography shows that female ''Osedax roseus'' were present on the remains of the carcase two months later and that they were fecund three months after that. These worms are sexually dimorphic, the male and female forms being markedly different. The females are large and the males are microscopic and live inside the parchment-like tubes which the female worms create. The authors of this study hypothesise that the sex of an egg may be determined by environmental factors, all eggs hatching near a new carcase being females, but these being heavily outnumbered by males at a later stage. This allows the females to produce many fertilised eggs which are able to disperse widely across the ocean. Few of these will land close enough to a sunken carcase to be able to develop into adult worms.

References

{{Taxonbar, from=Q2338983 Sabellida Animals described in 2008