Siphonosoma cumanense (Keferstein, 1867)
General description:
Cumana, Venezuela (Stephen and Edmonds, 1972).
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Sipuncula
Siphonosoma cumanense (Keferstein, 1867)
Siphonosoma cumanense (Keferstein, 1867)
General description:Siphonosoma cumanense is widespread and is the most common species of the genus. It is morphologically plastic and has a long list of synonyms reflecting its convoluted history in sipunculan literature (Cutler, 1994). This species is in general of medium size, but may exceed 400 mm in length. The semi-transparent skin allows the LMBs and, in live worms, the ocher-colored nephridia to be visible through the trunk wall. An internal characteristic differentiating this species is the origin of the dorsal and ventral retractor muscles at the same level.
Morphology:(From Stephen and Edmonds, 1972; Cutler, 1994)
External anatomy
Introvert shorter than the trunk, 1/3 of the trunk length, with no hooks, but has rings of fine papillae.
Skin is smooth, whitish or shades of grey (Kawauchi observed a pinkish color in specimens collected in Fort Pierce, Florida).
Tentacular crown surrounds the mouth.
Internal anatomy
18-26 anastomosing longitudinal muscles bands (LMBs) visible through the trunk wall.
Nuchal organ outside the ring of peripheral tentacles.
Ventral retractor muscles (VRM) and dorsal retractor muscles (DRM) originate at the same level.
Contractile vessel with many villi.
Nephridia short; nephridiopores open anterior to the anus.
Spindle muscle with 3 anterior roots and one posterior root attached to the posterior end of the trunk.
Size:Worms usually 100-200 mm long, but may exceed 400 mm (Cutler, 1994).
Associations:This species is found in Fort Pierce, Florida, in the same area as Sipunculus nudus (Kawauchi, personal observation).
Distribution:Widespread species found in tropical and subtropical oceans. Western Atlantic (Venezuela to Florida), many records from western Pacific and Indian oceans and Red Sea (Cutler, 1994).
Habitat:Specimens were recently collected in Fort Pierce, Florida in an exposed intertidal sand flatduring low tide (Kawauchi, personal observation).