Planctosphaera pelagica
| Planctosphaera pelagica | ||||||||||||
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Planctosphaera pelagica | ||||||||||||
| ( Spengel , 1932) |
Planctosphaera pelagica is the only known representative of the Planctosphaeroidea, besides the acorn worms (Enteropneusta) and the wing gills (Pterobranchia), the gill lobsters (Hemichordata) within the new mouths (Deuterostomia). So far only larvae of these animals are known, which is why an exact assignment is not possible.
Planctosphaera pelagica was first discovered in 1910 during the Norwegian deep-sea expedition of the "Michael Sars". The crew fished small transparent and spherical organisms from a depth of 270 meters, which were only described as larval forms in 1932 . It has not yet been possible to assign it to a full-grown animal species, but it is assumed that an acorn worm lives in the deep sea. The Planctosphaeroidea would no longer be a separate taxon, but would be classified in the acorn worms.
The larvae are relatively large with a diameter of 10 to 27 millimeters and are characterized by branched eyelash bands. The mouth field takes up about 2/3 of the surface of the animals, the intestine is V-shaped.
literature
- A. Goldschmid: Hemichordata (Branchiotremata). in: Wilfried Westheide: Special Zoology. Part 1. Protozoa and invertebrates. Gustav Fischer, Stuttgart- Jena 1996, Akademie Verlag, Heidelberg 2004, ISBN 3-8274-1482-2