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Sagitta (arrowworm)
''Sagitta'' is a genus of Chaetognatha The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can ..., a phylum commonly known as arrowworms or arrow worms. Phylum Chaetognatha comprises small marine worms. This genus is characterized in part by the distribution of the cilia on the body, the thick rays in the fins, and hooks which are not serrated.Kassatkina, A. P. (2007)Review of the genera of the family Sagittidae with separation of a new subfamily and description of a new species of the genus ''Sagitta'' from the Sea of Japan (Chaetognatha).''Zoosystematica Rossica'', 16(2), 157-162. As of 2007 there are 15 species. More have since been described.Kassatkina, A. P. (2008)New species of the genus ''Sagitta sensu str''.(Chaetognatha) from the Sea of Japan with description of an original stain ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chaetognatha
The Chaetognatha or chaetognaths (meaning ''bristle-jaws'') are a phylum of predatory marine worms that are a major component of plankton worldwide. Commonly known as arrow worms, about 20% of the known Chaetognatha species are benthic, and can attach to algae and rocks. They are found in all marine waters, from surface tropical waters and shallow tide pools to the deep sea and polar regions. Most chaetognaths are transparent and are torpedo shaped, but some deep-sea species are orange. They range in size from . There are more than 120 modern species assigned to over 20 genera. Despite the limited diversity of species, the number of individuals is large. Arrow worms are usually considered a type of protostome that do not belong to either Ecdysozoa or Lophotrochozoa. Anatomy Chaetognaths are transparent or translucent dart-shaped animals covered by a cuticle. The body is divided into a distinct head, trunk, and tail. There are between four and fourteen hooked, grasping spines ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
