Nephasoma (Nephasoma) bulbosum (Southern, 1913)
General description:
Southern (1913) wrote: “The peculiarity of shape from which it derives its specific name is common to all the specimens.”
You are here
Home » Sipuncula » Animalia » Sipuncula » Sipunculidea » Golfingiiformes » Golfingiidae » Nephasoma » Nephasoma (Nephasoma) » Nephasoma (Nephasoma) bulbosum (Southern, 1913) -
Sipuncula
Nephasoma (Nephasoma) bulbosum (Southern, 1913)
Nephasoma (Nephasoma) bulbosum (Southern, 1913)
General description:(From Southern, 1913)
The original description of this species was based on observations of 8 specimens collected in the same haul with fifty specimens of Phascolosoma muricaudatum (= Golfingia muricaudata). The bulbous character of the anterior portion of the trunk is due to unequal expansion, and thus is not a specific character. On the other hand the filiform nature of the posterior part of the trunk is shown in all the specimens and it is probably the normal condition.
Nephasoma (Nephasoma) bulbosum (Southern, 1913)
General description:Off Southwest Ireland, N 51.8 W 12.191667 (Southern, 1913)
Nephasoma (Nephasoma) bulbosum (Southern, 1913)
General description:(From Southern, 1913)
This hookless species has a peculiar shape. The anterior part of the trunk is swollen and has a transparent thin wall. The posterior portion of the trunk is long, slender and has thicker wall resembling a tail.
Look alikes:(From Cutler & Cutler, 1986)
This species appears similar to N. flagriferum in having a tail and papillae on the posterior end of the trunk, but both structures very much smaller in this species. Apart from the shape of the body, N. bulbosum resembles N. eremita in many ways, including the apparent absence of hooks.
Morphology:External anatomy
(From Southern, 1913)
The introvert is about a third of the trunk length.
No hooks were observed on the introvert.
The anterior portion of the trunk is swollen and has a thin and transparent wall. Posteriorly the wall becomes thicker, and the trunk long and more slender, resembling a tail. However, this latter portion is not really a caudal appendage. The nerve cord extends into the distal tip of trunk, unlike the condition of other species that have a true caudal appendage (e.g. N. flagriferum).
Sixteen to 18 tentacles moderately long surround the mouth.
There are few small papillae on the introvert. On the trunk there are numerous and small cylindrical papillae, 2-6 times as long as thick, and surrounded by a delicate granular ridge.
External anatomy
(From Southern, 1913)
The trunk body wall has a continuous longitudinal muscle layer.
Two slender ventral retractor muscles attached to the trunk body wall on either side of the nerve cord behind midway between the anus and the posterior end of the trunk.
Two long and slender free nephridia, open anterior to the anus.
Intestine with about 20 coils, not attached to the posterior end of the trunk.
Size:The total length (introvert plus trunk) of the largest specimen is 55 mm, of which the trunk is 43 mm and the introvert 12 mm Southern (1913).
Associations:Golfingia muricaudata (Southern, 1913).
Distribution:Off Ireland and northeast United States, bathyal depths (Cutler & Cutler, 1986).
Habitat:Ooze (Southern, 1913).