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UTAS Home > IMAS Home > Image Key > Copepoda > Cyclopoida > Corycaeidae >  Onychocorycaeus agilis

Onychocorycaeus agilis

Dana (1849)

Download a fact sheet for Onychocorycaeus agilis (PDF 400KB)


Phylum Arthropoda
Subphylum Crustacea
Class Maxillopoda
Subclass Copepoda
Order Cyclopoida
Family Corycaeidae
Genus Onychocorycaeus
Species agilis


  • Female: 1.00 - 1.16 mm
  • Male: 0.75 - 1.40 mm

Distinguishing characters

  • Peg like endopod of P4 with single seta
  • Proportional length of urosome somites and caudal rami
  • Female with very wide cephalosome
  • Male with long distal hook on A2 and minute ventral hook on genital somite
  • Both sexes long caudal rami compared to other Onychocorycaeus


  • May have minute median hook on ventral proximal corner of genital somite
  • Caudal rami just longer than anal somite and slightly shorter than genital somite


  • Prosome robust, 1.5 times as long as urosome
  • 2nd segment of antenna very broad, 2 teeth on inner distal margin
  • P4 endopodite has one seta
  • Urosome and caudal rami slender
  • Anal somite 2 times as long as wide
  • Caudal rami slightly longer than anal somite and same length as genital somite


  • Epipelagic
  • Coastal and oceanic
  • Australian distribution includes Christmas Island, Great Barrier Reef, New South Wales and North West Cape
  • World distribution: tropical and subtropical waters of the Pacific and Indian oceans, also found off South Africa


  • Females carry egg sacs
  • Carnivorous


  • Bradford-Grieve, J. M., E. L. Markhaseva, et al. (1999). Copepoda. South Atlantic Zooplankton. D. Boltovskoy. Leiden, The Netherlands, Backhuys Publishers. 1: 869-1098.