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Oithona tenuis

Rosendorn (1917)

Download a fact sheet for Oithona tenuis (PDF 239KB)


Phylum Arthropoda
Subphylum Crustacea
Class Maxillopoda
Subclass Copepoda
Order Cyclopoida
Family Oithonidae
Genus Oithona
Species tenuis


  • Female: 1.11 - 1.25 mm

Distinguishing characteristics

  • Very long and narrow prosome
  • Rostrum is more attenuated than other Oithona


  • Very difficult to identify


  • Prosome elongate oval in dorsal view
  • Cephalosome produced anteriorly into small rostral process in dorsal view
  • Cephalosome in lateral view bent ventrally into sharply pointed rostrum
  • Slender, greatest width at posterior end of cephalosome
  • Pr length 3.2-3.5 width
  • Pr:Ur 1.0-1.1
  • Genital somite slender, only slightly swollen laterally
  • Dorsal setae and inner medial apical setae on caudal rami thick
  • Differentiated from other large Oithona as is long and narrow and the rostrum more attenuated




  • Mckinnon pers. comm.
  • Nishida, S. (1985). "Taxonomy and distribution of the family Oithonidae (Copepoda, Cyclopoida) in the Pacific and Indian oceans." Bulletin of the Ocean Research Institute, University of Tokyo. Tokyo. no. 20: 1-167.
  • Nishida, S. (1986). "A new species of Oithona (Copepoda, Cyclopoida) from the neritic waters of Australia." Journal of Plankton Research 8(5): 907-915.