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Clausocalanus pergens

Farran (1926)

Download a fact sheet for Clausocalanus pergens (PDF 343KB)


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


  • Female: 0.87 - 1.22 mm
  • Male: 0.65 - 0.99 mm

Distinguishing characteristics

  • Form of seminal receptacle, ventral lobe large in lateral view, dorsal lobe short and finger like
  • Shape of forehead and rostrum
  • Prosome : Urosome ratio
  • Similar to females of C.brevipes & C.parapergens.
  • Similar to males of C.paululus but C. pergens is more slender, longer and the prosome is less tapered


  • Rostrum in lateral view knoblike and protruding ventrally
  • Longer ramus of P5 and genital pore on left side
  • Left P5 longer than urosome, right P5 2 segmented, distal segment small


  • Rostrum in lateral view slender and curved ventroposteriad
  • P5 segment 3 more than twice as long as segment 1
  • Prosome:urosome ratio 2.57-3.00:1
  • Ventral profile of genital segment in lateral view somewhat convex, but without a definite step
  • Genital somite more than1.5 times as long as urosome somite 3
  • Ventral lobe of seminal receptacle in lateral view large and visible anterior to base of seminal receptacle dorsal lobe
  • Dorsal lobe short and finger like
  • Dorsal and ventral lobes visible in ventral view


  • Epipelagic, bathypelagic.
  • Warm temperate, circumglobal.
  • The distribution in Australia includes the south east



  • 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