Bigelow, 1911
Description
Nectophore [Nectopyramis thetis ]: a single, pyramidal definitive nectophore. The deep but narrow hydroecium extends almost the length of the ventral surface. The shallow nectosac has thick enclosing lips around its ostium and its radial canals arise separately from the somatocyst. The latter also has two hydroecial branches, which themselves divide further, arising close to a central organ.
Eudoxid: bract resembles nectophore in shape and canal system. The dorsal canal is forked characteristically near its apex, and there is a prominent central organ. The large asexual nectophore is nearly enclosed by the bract.
Size
Nectophore up to 20 mm in height.
Depth range
Mesopelagic depths, commonly between 400 and 700 m.
Remarks
The Genus Nectopyramis contains a group of prayid siphonophores with asymmetric nectophores, bearing rounded ridges of serrations. The eudoxid bracts resemble the nectophores in appearance, and may bear special nectophores.
Distribution in the North Sea
Regarding its usual depth distribution unlikely to occur in the (northern) North Sea; a few records are known from north-west off Scotland.
World distribution
Nectopyramis thetis is best known from the North Atlantic Ocean, but it also occurs in the Indian and Pacific Oceans.
[After Kirkpatrick and Pugh, 1984]