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Pleuromamma gracilis

(Claus, 1863)

Download a fact sheet for Pleuromamma gracilis (PDF 515KB)


Phylum Arthropoda
Subphylum Crustacea
Class Maxillopoda
Subclass Copepoda
Order Calanoida
Family Metridinidae
Genus Pleuromamma
Species gracilis


  • Female: 1.60 - 2.55 mm
  • Male: 1.51 - 2.25 mm

Distinguishing characteristics

  • Cephalosome with short, acute apical process
  • Rostrum massive with 2 hairy filaments
  • Typically have red/brown button on the side of body around the junction of first body somite - depending on species can be on left or right side
  • Female P5 with 3 free segments and 3 long setae or with 1 free segment and 3 short spines on distal segment
  • Male right P5, terminal segment strongly curved, round; preceding segment with long curved inner spine
  • Urosome often asymmetrical with curved somites and setal bundles


  • Pigment spot on right side
  • Left A1 geniculate, toothed ridges on segments 17, 18, 19-21, serrations variable
  • P2 endopod segment 1 with denticles on right side only
  • Distal segment of right P5 elongate, slightly less wide than other related forms, penultimate segment has a curved process with a double row of blunt tubercles


  • Pigment spot on right side
  • Proximal segments of A1 with small low denticles
  • P5 2-segmented (with 1 free segment); distal segment with 3 terminal spines and 2 thin outer spines
  • Very similar to P. borealis and P. Piseki, look at form of P5 and size

(Bradford-Grieve 1999, Zheng 1982)


  • Mesopelagic - epipelagic
  • Oceanic
  • Widespread in all oceans
  • Found throughout Australian oceanic waters


  • Produces 3-4 generations year-1
  • Forms large swarms, up to 100 m in length
  • Produces bioluminescence that is stronger at night; luminescent glands are present on prosome, the bases of the swimming legs and antennules
  • Undergoes diel vertical migration over hundreds of metres
  • Display negative phototaxis
  • Suspension feeders


  • Bradford-Grieve, J. M. and Markhaseva, E.L. (1999). Copepoda. South Atlantic Zooplankton. D. Boltovskoy. Leiden, The Netherlands. Backhuys Publishers. 1: 869-1098.
  • Buskey, E.J., Baker, K.S. and Smith, R.C. (1989). Photosensitivity of the oceanic copepods Pleuromamma gracilis and Pleuromamma xiphias and its relationship to light penetration and daytime depth distribution. Marine Ecology Progress Series¡¡55(2-3): 207-216.
  • Shmeleva, A.A. and Kovalev, A.V. (1974). Cycles biologiques des Copepods (Crustacea) de la Mer Adriatique. Bollettino Pesca Piscic Idrobiol 29: 49-70.
  • Wiebe, P.H. (1970). Small-scale spatial distribution in oceanic zooplankton. Limnol. Oceanogr. 15: 205-217.
  • Zheng, Z., Li, S., Li, S.J. and Chen, B. (1982). Marine planktonic copepods in Chinese waters. Shanghai Sc. Techn. Press.