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Acrocalanus gibber

Giesbrecht (1888)

Download a fact sheet for Acrocalanus gibber (PDF 389KB)


Phylum Arthropoda
Subphylum Crustacea
Class Maxillopoda
Subclass Copepoda
Order Calanoida
Family Paracalanidae
Genus Acrocalanus
Species gibber


  • Female: 0.93-1.13 mm
  • Male: 0.94-1.24 mm

Distinguishing characteristics

  • Distal toothed outer border of exp3 P4 is 60% of length of proximal part
  • Female P5 is rudimentary
  • Male P5 only present on left


  • Prominent hump on dorsal cephalosome
  • P5 only visible on left and extends to end of urosome somite 3 or start of 4
  • Left P5 very simple, 5 segmented with 2 tiny spines on end of last segment
  • Males can be confused with male Paracalanus due to small transparent swelling on dorsal profile, differs from male Paracalanus, as male A. gibber has longer 2nd urosome somite, and P5 right is absent


  • Deep body in lateral view, pronounced hump on cephalosome
  • A1 exceeds caudal rami by 2 terminal segments
  • Distinct though partial line of separation of cephalosome and 1st pedigerous somite visible
  • Distal teeth on P4 are strong when compared to A. longicornis
  • Distal toothed outer border of exp3 P4 is 60% of length of proximal part
  • Genital somite longest, with prominent ventral swelling
  • Females can be confused with Paracalanus, but in Acrocalanus P5 is absent



  • Generally found in tropical regions but can be transported into temperate regions with warm currents
  • Generally more abundant in inshore waters
  • Abundances in the Great Barrier Reef peak between January to April
  • When present, A. gibber is highly abundant
  • Herbivorous filter feeders
  • Broadcast spawners


  • 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. and A. Colefax (1940). "The plankton of the Australian coastal waters off New South Wales Part I." Publications of the University of Sydney: 210.
  • 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.