Monday, September 14, 2015

A new tubeworm: Lamellibrachia sagami

Worms of the genus Lamellibrachia are related to the giant tube worm, Riftia pachyptila, which is known to live close to black smokers. All these worms can tolerate extremely high hydrogen sulfide levels and many of them are known to grow quite large (3 m). Like other tube worms, they are marine and benthic. Their primary food is derived from the sulphide-rich fluids emanating from the environment they live in. The sulphides are metabolized by symbiotic bacteria living in an internal organ, the trophosome.

Today's species was found off the coast of Japan in a cold seep at about 1100 m depth.  A cold seep is an area of the ocean floor where hydrogen sulfide, methane and other hydrocarbon-rich fluids slowly pass through small openings in the sea floor. They often form a brine pool. The word cold has nothing to do with the temperature. Actually, the temperature of a cold seep is often slightly higher than its surroundings. Cold seeps constitute a biome supporting several endemic species.

The species name refers to the coastal area of Sagami Bay, the type locality. 

For the experts: A new vestimentiferan tubeworm species of the genus Lamellibrachia Webb, 1969 is described. It was collected from cold seep areas off Hatsushima in Sagami Bay and at the Daini Tenryu Knoll in the Nankai Trough (606–1170 m depth). Lamellibrachia sagami sp. nov. differs from seven congeneric species in the following character states; showing a wider range of diameter of vestimental and trunk plaques than L. barhami, L. luymesi, L. satsuma and L. anaximandri; and having more numerous sheath lamellae (3–6 pairs) than L. juni (2–3 pairs) but fewer than L. victori (7 pairs) and L. columna (8–16 pairs).

No comments:

Post a Comment