Drepanopsis frigidus   Wolfenden,  1911 (Copepod)
Organism information awaits expert curation
Taxonomy
Kingdom:Animalia
Phylum:Arthropoda
Class: Maxillopoda
Order:Calanoida
Family:Clausocalanidae

Description
Size (female): length 2.28 mm.

The proportional lengths of the cephalothorax and abdomen are as 98 to 23, the abdomen thus being contained 4.26 times in the length of the anterior region of the body.
The head is rounded and terminates ventrally in a curved and backwardly-directed median spine instead of in a bifid rostrum. The head and 1st thoracic segment are fused. Thoracic segments 4 and 5 are separate and the 5th segment is produced back in a sharply pointed wing.
The abdomen consists of four segments. The full length of each segment being in the proportions 39: 13: 12: 15: 21. The furcal rami are somewhat longer than the anal segment and the length is 1.75 times the breadth. There are a few scattered hairs on the inner margin of the ramus.
The 1st antenna reaches to the posterior thoracic margin, or about half way along the genital segment. It consists of 24 free segments, segments 8 and 9 being fused together. In the 2nd antenna the two rami are of nearly equal length, the endopod being slightly longer and the proportional lengths being 72 to 77. In the exopod the 1st and 2nd segments are separate, and the 2nd segment bears three rounded prominences on its anterior margin, of which the 2nd and 3rd each bear a short stiff seta. The 1st basal segments bears a row.
The mandibular palp consists of a swollen basal segment and the usual two rami, of which the endopod is about half the length of the exopod and consists of two segments.
In the 1st maxilla, the 2nd and 3rd inner lobes each bear 4 setae and the 3rd lobe bears a number of hair-like spines on its anterior aspect. The basal segment bears 5 setae and is armed on its anterior and outer aspects with a number of short hair-like spines. The endopod is clearly marked off from the basal segment, and the three segments bear 4, 5 and 7 setae respectively. In the 2nd maxilla, the 2nd, 3rd and 4th lobes each bear a row of spines. All the setae arising from the endopod are unmodified.
The maxilliped bears a row of needle-like spines on the proximal part of the anterior border of the 2nd basal segment.
The 1st swimming leg has three-jointed exopod and a single –jointed endopod. Each segment of the exopod bears a single marginal spine, and the endopod possesses the usual swelling on its outer margin, which is crowned with a row of short spines.
In the 2nd swimming leg the exopod consists of three segments and the endopod is two-jointed; the 1st basal bears a number of hair-like spines on the posterior and outer aspects of the proximal and a series of smaller spines along the outer aspect of the middle third. Basal 2 bears a series of small spines on its posterior aspect. The 1st segment of the endopod bears two coarse spines, and the distal segment is armed with three groups of 3, 2 and 3 spines respectively.
In the 3rd swimming leg, the 1st basal segment bears a number of hair-like spines on the outer margin of the proximal third and a series of smaller spines along the margin of the middle third. The 2nd basal bears a number of small spines on its posterior aspect. The exopod and endopod each consist of 3 segments. All the marginal spines on the exopod are sub-equal. Exopod 1 bears 2 spines near the base of the marginal spine, and the distal margin of exopod 2 is armed with a row of small needle-like spines. The end-spine is considerably longer than the distal segment. The endopod bears 2 spines on the posterior aspect of the 1st segment; a curved row of spines, 6 in all, on the 2nd segment, and a group of 3 small spines proximally and a pair of larger spines distally on the 3rd segment.
The 4th swimming leg closely resembles the 3rd in its general form but there are no spines on any of the segments, except a row of small needle-like spines along the distal margin of the 2nd segment of the exopod. The third segment of the exopod in the 2nd-4th swimming legs bears 4 setae.


Synonym (s)
Drepanopsis frigidus Wolfenden, 1911
Drepanopsis frigidus Farran, 1929

Common Name (s)
Economic Importance and Threats

Ecology

Biogeography


• Kerala, Off Kochi (Lat: 10.43) (Long: 74.54) INDIA (Record: 28/04/1925)

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 - http://www.marinespecies.org

Page last updated on:2011-03-11

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