Stauroteuthis syrtensis

This species has been frequently observed in waters off the continental shelf of eastern North America, but has also been found in locations in the northeastern Atlantic. (Collins and Henriques, 2000; Collins, 2002)

Stauroteuthis syrtensis is described as "benthopelagic" -- being found in open water, but near the bottom. and can be found in depths of the ocean ranging from 500-4000m. This large range seems to relate to water temperature. Stauroteuthis syrtensis prefers a temperature of 3.0 - 3.3 degrees Celsius. (Collins and Henriques, 2000; Collins, 2002)

This species belongs to the cirrate octopods, distinguished by fins used for swimming, an internal shell (to which the fins attach) and cirri, paired filaments or papillae, on each sucker. Like other species in the Stauroteuthidae, S. syrtensis has a u-shaped internal shell, and secondary webbing that connects the arms to the primary web. This allows the arms to move inwards towards the mouth without collapsing the large bell-shaped web of skin that forms around arms. The web covers nearly two thirds of their total length ending at sucker 25, with each arm bearing between 55 to 65 suckers. The average arm length is about 70-85% of its total length with total lengths ranging from 280-500mm.

The body of these animals is soft and gelatinous, and is often heavily damaged in trawls and collections. It is often found hanging in the water with its webbed arms forming a bell shape. There are large glands near the mouth that may produce mucous to trap small prey animals.

Males have sexually dimorphic suckers. The first 8 suckers are barrel shaped, suckers 9 to 22-25 are enlarged and pointed. Suckers 9 to 12 are very closely packed and suckers 13 to 18 are the largest with a diameter of about 6.5 mm. Females have smaller suckers with suckers 1 to 3 as the largest with a diameter of 2.2 mm. Suckers 1 to 4 are very tightly packed, but suckers 5 to 24 are well separated. In both sexes, the suckers diameter decreases dramatically after sucker 25 nearing where the web ends. Both male and females have three kinds of suckers, proximal, mid arm, and distal. This sexual dimorphism in the size and shape of the suckers is unique to the species, and is probably related to sperm transfer or other reproductive activity. (Collins and Henriques, 2000)

Because juvenile specimens have not been found, little is known about how Stauroteuthis syrtensis develops. However, the large size of the eggs suggests direct development. (Collins and Henriques, 2000)

The longevity of Stauroteuthis syrtensis is unknown.

Staurotheuthis syrtensis have mostly been found in a bell posture with their arms extending and their web spread. In the bell posture, they use their fins to swim. They can also move by expanding their web and then contracting it to expel water and propel them through the ocean. Live animals in the wild have only been found alone, not in groups. (Collins, Young, and Vecchione, 2008; Vecchione, 2000)

Communication in Stauroteuthis syrtensis has not been observed. The species has large eyes, and is likely sensitive to chemicals and touch.

Stauroteuthis syrtensis are unique among other cirrate octopods in that they have modified suckers that are capable of producing blue-green bioluminescence with a maximum wavelength of 470nm. These modified suckers are unlike other suckers because they are not able to attach. Their use is not well understood, but it is suggested that they may be used to attract prey or be used to attract a mate. (Collins, Young, and Vecchione, 2008; Johnsen et al., 1999)

No specimens have been seen capturing prey, but the stomach of preserved specimens contained small crustaceans, mostly copepods. The bell shape of the web, along with mucus produced by glands around the mouth, maybe be used to capture zooplankton. The bioluminescence of the suckers is also thought to be used to attract prey, but this has not yet been confirmed. (Collins and Henriques, 2000; Collins, Young, and Vecchione, 2008; Johnsen et al., 1999)

Because little has been witnessed in the wild about this species, its predators have not been observed. When observed, Staurotheuthis syrtensis is normally in a bell posture. When disturbed though, the animal goes into a balloon posture with the arms closed at the tips. In the balloon posture, the fins remain motionless. Staurotheuthis syrtensis has also been seen in a pumpkin posture when threatened which is like the balloon posture, but smaller. When trying to escape, the Staurotheuthis syrtensis will go back in to the bell posture and move its fins vigorously. (Collins, Young, and Vecchione, 2008; Johnsen et al., 1999)

There are no known adverse effects of Stauroteuthis syrtensis on humans.

S. syrtensis does not appear to have any positive importance for humans at this time.

The population size of this species is unknown. It has not been evaluated by the IUCN, and is not listed in CITES or under the U.S. Endangered Species Act.