University of Tasmania, Australia

UTAS Home | UTAS Staff | UTAS Contacts


UTAS Home > IMAS Home > Image Key > Copepoda > Calanoida > Clausocalanidae >  Clausocalanus farrani

Clausocalanus farrani

Sewell (1912)

Download a fact sheet for Clausocalanus farrani (PDF 366KB)


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


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

Distinguishing characteristics

  • Female C. farrani is distinct from all other Clausocalanus spp. (except C. jobei) in having a ventral protuberance of genital somite anterior to genital pores
  • Shape of forehead and rostrum, C. jobei and C. farrani differ in form of rostrum in lateral view
  • Prosome : Urosome ratio
  • Male similar to but stouter in body than C. arcuicornis


  • Rostrum in lateral view knoblike and protruding ventrally
  • Longer ramus of P5 and genital pore on left side
  • Left P5 longer than urosome, 5th segment armed distally with slender, usually straight setae
  • Right P5 short, 2 segmented, segment 2 very small


  • Rostrum in lateral view straight or slightly curved, short, thick and directed ventrad or slightly ventroposteriad
  • Terminal points of P5 segment 3 divergent and always spinulate only in inner margins
  • Prosome:Urosome ratio 2.3-2.64:1
  • Ventral profile of genital somite in lateral view protuberant anterior to genital pores
  • Separation of seminal receptacle dorsal and ventral lobes weak both in lateral and ventral view
  • Genital somite more than 1.5 times as long as urosome somite 3





  • 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