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Oithona atlantica

Farran (1908)

Download a fact sheet for Oithona atlantica (PDF 436KB)


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


  • Female: 1.14 - 1.43 mm

Distinguishing characters

  • Very similar to O. plumifera but no tuft of hairs on genital somite
  • Very similar to O. longispina but usually larger
  • P4 endopod segment 3 outer marginal distal spine is straight and as half as long as apical spine


  • Very difficult to identify


  • Prosome rounded, fusiform in dorsal view, greatest width at posterior end of cephalosome
  • Head narrowing anteriorly to pointed rostrum in dorsal view
  • A1 long, 1.4-1.6 times prosome
  • Prosome length 2.2-3.1 times width
  • Prosome:urosome 1.1 -1.3
  • Re3 of P4 outer marginal spine curved at base and shorter than apical spine (cf O. longispina where Re3 of P4 outer marginal spine is straight and as long as the apical spine)
  • Anterior third of genital somite swollen laterally
  • Spermathecae spherical




  • 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.