[2] Lacking an intermediate web is what causes the indentations in the outer edge of their arms that make them look like an umbrella.

Another defensive mechanism that Opisthoteuthidae have been observed using is web-inversion which is when they have their arms turned upwards and their web with the oral surface facing outwards.

It has been noted that these defensive behaviors are the positions the octopuses may go into while feeding as well, but it is possible that this could be because of the stress of being captured and placed in an aquarium to be observed.

It will erect its mantle, curve the outer edges of its arms inwards to have them be the only part making contact with the floor.

Family Opisthoteuthidae has classically contained a single genus, Opisthoteuthis, which has recently been split into three genera on the basis of differences in enlarged suckers on male specimens.