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Clausocalanus furcatus

Brady (1883)

Dowload a fact sheet for Clausocalanus furcatus (PDF 312KB)


Phylum Arthropoda
Subphylum Crustacea
Class Maxillopoda
Subclass Copepoda
Order Calanoida
Family Clausocalanidae
Genus Clausocalanus
Species furcatus


  • Female: 0.94 - 1.31 mm
  • Male: 0.70 - 0.92 mm

Distinguishing characteristics

  • The only Clausocalanus with genital somite shorter than next two somites in female
  • Form of seminal receptacle
  • Shape of forehead and rostrum
  • Prosome: urosome ratio
  • Males differ from all other species of Clausocalanus in the shape of the rostrum and in usually having the longer leg of the pereiopod 5 and genital pore on the right side.


  • Rostrum not well developed and not protruding ventrally
  • Longer pereiopod 5 and genital pore usually on right side (sometimes left). This is different to most other Clausocalanus males
  • Longer leg of pereiopod 5 longer than urosome; shorter leg of pereiopod 5 usually bimerous, distal segment small
  • Prosome:Urosome ratio 2.24-2.50:1
  • Urosome somite 2 a little longer than other urosome somites


  • Rostrum in lateral view is thick, short and slightly curve, bifurcated at tip
  • Pereiopod 5 coxa very short
  • Prosome:Urosome ratio 2.24-2.50:1
  • Urosome longer than 4th legs
  • Genital somite shorter than next two somites
  • Genital somite profile in lateral view rather uneven
  • Seminal receptacle is large and bulbous
  • Caudal rami twice as long as wide


  • Epipelagic
  • Inshore coastal, coastal and oceanic
  • Australian distribution includes Tasmania, North West Cape, New South Wales and Great Barrier Reef
  • World distribution: widespread in tropical and subtropical waters of the Pacific, Indian and Atlantic Oceans


  • Tropical-subtropical, circumglobal
  • Can be found in temperate regions with warm water movement
  • Found in Tasmania from February - July, most abundant between March and May, coinciding with the extension of the East Australian Current
  • C. furcatus females carry their eggs in a cylindrical mass wrapping the abdomen
  • C. furcatus feeds, reproduces and develops at low phytoplankton concentrations, ideal for open ocean environments
  • Development times for C. furcatus from hatching to adulthood is 13 - 21 days at 20°C
  • Herbivorous filter feeder


  • Frost B, Fleminger A (1968). A revision of the genus Clausocalanus (Copepoda: Calanoida) with remarks on distributional patterns in diagnostic characters. Bulletin of Scripps Institution of Oceanography 12:1-235
  • Razouls C., de Bovée F., Kouwenberg J. et Desreumaux N., 2005-2009. Diversity and Geographic Distribution of Marine Planktonic Copepods. Available at
  • Kimmerer et al (1985)
  • Mazzocchi & Paffenhöfer (1998)