Osedax mucofloris Glover, Kallstrom, Smith and Dahlgren, 2005
Osedax worms are marine annelids closely related to the deep sea vent/seep-associated vestimentiferan worms. The sessile (i.e., fixed in one place) females bore into the bones of whale carcasses--and possibly bones of other vertebrates (Rouse et al. 2004; Glover et al. 2005; Vrijenhoek et al. 2008).
Osedax mucofloris, only the third Osedax species described and the first Osedax known from the Atlantic Ocean, was described by Glover et. al (2005) from an experimentally deposited carcass of a Minke Whale (Balaenoptera acutorostrata) at a depth of 125 meters in the North Sea. This species has also been collected in the North Sea from submerged Pilot Whale (Globicephala melas) bones at a depth of 30 meters and Minke Whale (Balaenoptera acutorostrata) bones at a depth of 125 meters (Dahlgren et al. 2006). Osedax worms were previously known only from deep-sea (1500 to 3000 meter) whale-falls in the northeast Pacific. Glover et al. discuss the implications of such a global distribution of the genus Osedax for understanding the phylogeography, historical biogeography, and diversification of this group. (Glover et al. 2005)
Glover et al. (2005) reported that disturbance caused the worms to retract completely into the bone. However, when placed in aquaria, with clean, chilled seawater, they would emerge from the bone and be clearly visible to the naked eye. Over a period of several minutes, the worms would first extend the palps, and then the oviduct (see video here). Any disturbance to the aquarium tank would result in the animals immediately withdrawing into the bone.
Many Osedax species have numerous pinnules on their palps that give the crown a feathery appearance. Of the known Osedax species, only O. mucofloris and O. frankpressi have pinnules oriented all inward (the pinnules in the other species being turned outward, both inward and outward, or absent). Most known Osedax species have red palps (the palps of O. frankpressi are red with two white lateral stripes in living worms), but the palps of Osedax mucofloris are white to pink. (Rouse et al. 2004; Vrijenhoek et al. 2009)
Based on available data (which are clearly very limited), Osedax mucofloris is associated with shallower depths than other known Osedax species, having been collected at 30 and 125 meters.
Detailed examination of at least 50 mature specimens indicated an absence of the dwarfed males reported for northeast Pacific Osedax species. However, O. mucofloris appeared able to reproduce and grow to maturity within one month on defaunated bones placed into aquaria. (Glover et al. 2005)