Scolecithrix nicobarica   (Sewell,  1929 ) (Copepod)
Organism information awaits expert curation
Class: Maxillopoda

Image copyrights: Biotech Books

a. The whole animal from above (female)

Size (male & female): length 1.08 mm.

Female: The proportional lengths of the cephalothorax and abdomen are as 46 to 11, so that the abdomen is contained 4.2 times in the length of the anterior region of the body. The cephalothorax is moderately robust and tapers somewhat towards the anterior end the broadest part being in the neighbourhood of the posterior margin of the 1st thoracic segment. The cephalon and 1st thoracic segment are fused, as also are the 4th and 5th thoracic segments. The rostrum is composed of two short stout spines, each terminating in a fine flagellum. The posterior thoracic margin is curved and is slightly indented.The abdomen consist of four segments. The furcal rami are short and broad and bear four setae on their distal margin, of which the 2nd is twice as long as the 3rd.

The 1st antenna reaches back to slightly beyond the posterior margin of the thorax and consists of only 20 free segments. Segments 1 and 2 are fused together and so are segments 8 to 10 and segments 12 and 13; segments 24 and 25 are also fused. Segment 3 bears a long and a short ‘aesthetask’ as also does segment 7; segment 9 bears a single long sensory filament and segments 18, 19 and 21 each bear a short sensory filament.

In the 2nd antenna the exopod is twice the length of the endopod. The 1st swimming leg possesses a three-jointed exopod and a single jointed endopod. The 1st basal segment bears a row of fine spines across its outer surface. The 1st segment of the exopod is devoid of a marginal spine; exopod 2 and 3 each bears a marginal spine, the two being subequal, and the end-spine is long and slender and is more than the length of the two end-segments. Exopod 3 bears only three setae. The endopod exhibits onits outer margin a rounded swelling which is fringed with needle-like spines.

The 2nd, 3rd and 4th swimming legs are armed with numerous spines on the surface of the segments.

The 5th pair of legs is completely absent in this sex.

Male: The proportional lengths of the cephalothorax and abdomen are in this sex 43 to 14, so that the abdomen is contained only 3.1 times in the length of the anterior region of the body. The general form of the body is as in the female.

The abdomen consists of five segments.
The swimming legs are as in the female.

Synonym (s)

Common Name (s)
Economic Importance and Threats

Habitat:  Pelagic


• Andaman and Nicobar Islands, Nicobars, Nankauri Harbour INDIA
• Bay of Bengal INDIA

Literature Source(s)
  • Sewell, RBS (1999) The copepoda of Indian seas Biotech Books, Delhi, India 407 pp Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Sealifebase Available at -
  • Fernandes, V (2008) The effect of semi-permanent eddies on the distribution of mesozooplankton in the central Bay of Bengal Journal of Marine Research Sears Foundation for Marine Research 66 465–488 Available at - NIO,Goa

Page last updated on:2011-03-15

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