Gaertner’s spoon worm (Thalassema thalassema)
|Researched by||Saskiya Richards||Refereed by||Admin|
|Other common names||-||Synonyms||-|
Thalassema thalassemum is an unsegmented, soft-bodied spoon worm. The main body, or trunk, is bilaterally symmetrical and reaches a length of up to 2-7 cm. The colour of the trunk varies between individuals and may be blue, grey, yellow, pink or purple. On the surface of the trunk are numerous papillae that are arranged in rings around the body, and which increase in number towards the posterior. Along the middle of the ventral surface of the body there is sometimes a single white line. The mouth is positioned at the base of the proboscis and behind this lies a pair of chaetae. The proboscis is coloured peach or cream, can extend up to 10-20 cm and may appear to have a ventral channel when its lateral margins roll inwards during feeding.
Recorded distribution in Britain and IrelandThalassema thalassemum is recorded from south-west England, south-west Wales, southern and western Ireland and south-west Scotland. In addition, it has been recorded at Strangford Lough, Northern Ireland, Isle of Man and off north Wales.
Global distributionThalassema thalassemum has been found in the Mediterranean, Japan, Louisiana, Sierre Leone and France.
HabitatThalassema thalassemum inhabits sandy or muddy sediments and rock crevices at both low and shallow water. It creates a u-shaped burrow within the sediment that is lined with mucus.
- Soft, plump, bilaterally symmetrical, cylindrical body of up to 2-7 cm.
- Proboscis of up to 10-20 cm.
- Mouth at base of proboscis.
- One pair of hooked chaetae located behind mouth.
- Numerous wart-like papillae arranged in rings.
- Colour of body blue, grey, yellow, pink or purple.
- Colour of proboscis peach or cream.
- End of proboscis either round or pointed.
Thalassema thalassemum is the smallest of the Echiurans. Its main body is capable of contracting to 2-3 cm. It is a deposit feeder, using its proboscis to secrete a mucus sheet that traps detritus. Thalassema thalassemum is gonochoristic, although there is no sexual dimorphism, and reproduces by external fertilization in the summer. A free-swimming planktonic larva stage develops from fertilized eggs before developing into the adult form. Thalassema thalassemum is mainly nocturnal.
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Last Updated: 03/07/2009