Sipunculus (Sipunculus) robustus Keferstein, 1865
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.
Uea, Wallis Island, Pacific Ocean (Stephen and Edmonds, 1972).
Type: Zoologische Institut Zoologisches Museum, Universitat von Hamburg, Hamburg, ZMUH (Cutler, 1985).
(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.
26-30 longitudinal muscle bands, usually 28-29.
A pair of free nephridia.
Brain with long and stringy lateral processes.
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
This species is found in warm shallow waters in the Indo-West Pacific Ocean, Red Sea, and Caribbean.