Osedax priapus
From Wikipedia, the free encyclopedia
| Osedax priapus | |
|---|---|
Scientific classification  | |
| Kingdom: | Animalia |
| Phylum: | Annelida |
| Clade: | Pleistoannelida |
| Clade: | Sedentaria |
| Order: | Sabellida |
| Family: | Siboglinidae |
| Genus: | Osedax |
| Species: | O. priapus |
| Binomial name | |
| Osedax priapus Rouse et al., 2015,[1] | |
Osedax priapus is a species of annelid polychaete worms that consume the nutrients inside the bones of dead whales or other vertebrates.
Unlike other species of Osedax, males of this species grow to full size and can feed independently of females, thus demonstrating reversal of sexual size dimorphism (SSD).[1][2]
Etymology
Anatomy
Like the females of other Osedax species, both sexes of O. priapus show three regions: the roots, the trunk, and the palps. The epidermis of the roots act as a 'drill' that secretes acid to burrow into the bone. The roots also contain symbiotic bacteria to absorb nutrients. This region also contains the gonads, either an ovary or testis in the case of O. priapus. The trunk is in a gelatinous tube that surrounds the main body of the worm which they can retract into. The trunk is muscular to allow the worm to pull into the tube when in danger. The palps act as gills for gas exchange. Individuals of O. priapus have a yellow patch of pigment on the prostomium, just under the palps. The males have been shown to stretch their trunk from lengths of 2 mm to 15 mm.[1]
The female worms have an ovisac below the trunk, and an oviduct among the four palps, like the females of other Osedax species. [1] They tend to be smaller than other species on average, with other O. priapus males still being one-third of their size.
The O. priapus males have testis sacs surrounded by the roots and a sperm duct connected to a seminal vesicle that opens just below the palps. The males have two palps rather than four, possibly to allow efficient sperm transfer. [1]
