(Eschscholtz, 1829)
Description
Anterior nectophore of polygastric stage [C.appendiculata-polygastr ]: very rigid in construction. Only three ridges reach the apex, one of the latter as well as the dorsal being incomplete. The angular mouth plate is divided. The hydroecium is claw-shaped, extending to about one sixth of the nectophoral height. The somatocyst arises at the apex of the hydroecium, and is long and spindle-shaped.
Posterior nectophore [C.appendiculata-postnect ]: slightly asymmetrical, with one basoventral process longer than the other. The basal parts of the ventral ridges are strongly serrated, each with a small but obvious tooth approximately at the ostial level. The apex of the nectophore is pointed.
Eudoxid [C.appendiculata-eudox ]: the bract is roughly conical with a small-shield, and a thickened, elongated phyllocyst. The gonophore has four longitudinal ridges, which bear small serrations basally.
Colour
The nectophores often become opaque on preservation.
Size
Anterior nectophore up to 20 mm in height.
Depth range
Occurring particularly in the upper 300 m.
Distribution in the North Sea
Probably not in the North Sea. Chelophyes appendiculata is found in occasional incursions of warmer waters on to the European Continental Shelf towards the northern North Sea. The species is often collected together with other species of siphonophore from warmer waters.
World distribution
Chelophyes appendiculata is probably the commonest species of siphonophore, and is abundant in the warmer waters of the World’s oceans. In the NE Atlantic this species is found rarely north of the frontal region of approximately 42°-46°N, which represents the boundary between those waters with a permanent thermocline, to the south, and the northerly waters where only a seasonal thermocline is developed.
[After Kirkpatrick and Pugh, 1984]