About Osedax fenrisi

Osedax fenrisi is a species of bone-eating worm in the family Siboglinidae, discovered on a whale carcass in the deep sea near Antarctica. This species is adapted to extreme environments, feeding on the lipids within whale bones through root-like structures that penetrate the bone. It relies on symbiotic bacteria housed in these root structures to metabolize the organic material. Named after the Norse god Fenrir, this species highlights the unique adaptations of deep-sea organisms to nutrient-limited habitats.

Animalia (Kingdom); Annelida (Phylum); Polychaeta (Class); Sedentaria (Subclass); Canalipalpata (Infraclass); Sabellida (Order); Siboglinidae (Family); Osedax (Genus); Osedax fenrisi (Species)

Osedax fenrisi Eilertsen, Dahlgren & Rapp, 2020

1. Eilertsen M H, Dahlgren T G, Rapp H T. A new species of Osedax (Siboglinidae: Annelida) from colonization experiments in the Arctic deep sea[J]. Frontiers in Marine Science, 2020, 7: 443. (Eilertsen et al., 2020)

Holotype female; preserved trunk 2.4 mm long, 0.3 mm wide; crown of palps 1.7 mm long. Pinnules long, some extending up to half the length of the palps, inserted dorsally, with a distal bulb or knob. Oviduct short, emerging from the rim of the trunk, extending between the base of the dorsal palps a quarter of the length of palps. Trunk with inconspicuous collar on anterior margin, thicker on the ventral side including a “bump”. No demarcation of upper and lower trunk. Live specimen with red palps. Color of trunk pale or white. Color of the collar not observed. Preserved specimens without pigmentation. Tube cylindrical and not very gelatinous. Root structure bulbous. Ovisac an ellipsoidal mass. Males not observed in 10 preserved specimens investigated with dissecting microscope.

named after the Fenris wolf, son of the Norse god Loki, for whom the vent field where the species was discovered is named

Aegirs Kilde Hydrothermal vent area, Arctic Mid-Oceanic Ridge 2340 m depth at 73.5671, 8.15881 (73 34' 01.6" N, 8 09' 31.70" E )