Sipunculus robustus
Sipunculus (Sipunculus) robustus Keferstein, 1865
- kingdom Animalia
- phylum Sipuncula
- class Sipunculidea
- order Sipunculiformes
- family Sipunculidae
- genus Sipunculus
- subgenus Sipunculus (Sipunculus)
Overview
General Description
This species is sometimes confused with S. nudus, but the free nephridia, a different number of LMBs, and the characteristic digitate processes of the brain are distinguishing characters of S. robustus.
Type
Type Locality
Uea, Wallis Island, Pacific Ocean (Stephen and Edmonds, 1972).
Type Material
Type: Zoologische Institut Zoologisches Museum, Universitat von Hamburg, Hamburg, ZMUH (Cutler, 1985).
Description
Morphology
(From Stephen and Edmonds, 1972; Cutler and Cutler, 1985 and Cutler, 1994).
Introvert shorter than the trunk, with triangular papillae covering the surface.
Trunk is cylindrical and the surface is divided into a large number of small rectangles by the intersection of the longitudinal and circular muscles.
Internal anatomy
26-30 longitudinal muscle bands, usually 28-29.
A pair of free nephridia.
Brain with long and stringy lateral processes.
Similar Species
This species is similar to Sipunculus nudus, however it is differentiated by the number of LMBs, the free nephridia, and the lateral long stringy brain processes. Cutler and Cutler (1985) believe that over the years S. robustus has been mistakenly identified as S. nudus and vice versa.
Ecology and Distribution
Distribution
This species is found in warm shallow waters in the Indo-West Pacific Ocean, Red Sea, and Caribbean.


