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Oithona nana

Giesbrecht (1893)

Download a fact sheet for Oithona nana (PDF 319KB)

Taxonomy

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

Size

  • Female: 0.49-0.59 mm

Distinguishing characteristics

  • Cephalosome narrow and truncated anteriorly in dorsal view, bent ventrally with blunt rostrum in lateral view (almost no rostrum)
  • Genital somite remarkably swollen laterally in anterior quarter. Anterior margin of swelling nearly semicircular in dorsal view

Male

  • Very difficult to identify

Female

  • Prosome oval in dorsal view, greatest width at anterior end of pedigerous somite 1
  • Cephalosome narrow and truncated anteriorly in dorsal view, bent ventrally with blunt rostrum in lateral view.
  • Prosome length 1.9-2.1 times width
  • Prosome:Urosome 1.0-1.2
  • A1 short, as long as prosome
  • Almost no rostrum
  • Genital somite remarkably swollen laterally in anterior quarter. Anterior margin of swelling nearly semicircular in dorsal view
  • Caudal rami dorsal seta, thin and narrow compared to other setae
  • Can confuse with O. attenuata
  • Can come in plumose form with plumose setae

Distribution

Ecology

References

  • 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.