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Acrocalanus gracilis

Giesbrecht (1888)

Download a fact sheet for Acrocalanus gracilis (PDF 332KB)


Phylum Arthropoda
Subphylum Crustacea
Class Maxillopoda
Subclass Copepoda
Order Calanoida
Family Paraclanidae
Genus Acrocalanus
Species gracilis


  • Female: 1.2-1.32 mm
  • Male: 0.88-1.00 mm

Distinguishing characteristics

  • Distal toothed outer border of exp3 P4 is 80% of length of proximal part
  • Female P5 is rudimentary
  • Male P5 only present on left


  • A1 reaches just beyond caudal rami
  • No hump on cephalosome
  • P5 left 5 segmented and reaches to end of urosome somite 2
  • P5 right is vestigial or absent


  • Cephalosome evenly rounded in lateral view
  • A1 exceeds end of caudal rami by 3-4 segments
  • Line between cephalosome and first pedigerous somite is rarely visible
  • Distal toothed outer border of exp3 P4 is 80% of length of proximal part


  • Epipelagic, sometimes deeper
  • Coastal and oceanic
  • Distribution in Australia includes Great Barrier Reef, Moreton Bay, North West Cape and New South Wales
  • World distribution: recorded from tropical regions of all oceans


  • Can be transported into temperate regions via warm water currents
  • More abundant offshore on the Great Barrier Reef
  • Herbivorous filter feeder


  • Bradford-Grieve, J. M. (1994). The marine fauna of New Zealand: Pelagic Copepoda: Megacalanidae, Calanidae, Paracalanidae, Mecynoceridae, Eucalanidae, Spinocalanidae, Clausocalanidae. National INstitue of Water and Atmospheric Research, Wellington, New Zealand.
  • Bradford-Grieve, J. M., E. L. Markhaseva, et al. (1999). Copepoda. South Atlantic Zooplankton. D. Boltovskoy. Leiden, The Netherlands, Backhuys Publishers. 1: 869-1098.
  • Conway DVP, White, R.G., Hugues-Dit-Ciles, J., Gallienne, C.P. and Robins, D.B. (2003). Guide to the coastal and surface zooplankton of the south-western Indian Ocean, Vol Occasional Publications No. 15. Marine Biological Association of the United Kingdom.
  • Dakin, W. J. & Colefax, A. N. (1940). The plankton of the Australian coastal waters off New South Wales, Volume 1, Australasian Medical Publishing Company, Limited.
  • Razouls C., de Bovée F., Kouwenberg J. et Desreumaux N., 2005-2009. Diversity and Geographic Distribution of Marine Planktonic Copepods. Available at
  • Thorrold, S. R. (1993). "Zooplankton community structure and copepod egg production in coastal waters of the central Great Barrier Reef lagoon." Journal of Plankton Research 15(12): 1387-1411.