Undeuchaeta bispinosa   Esterly,  1911 (Copepod)
Organism information awaits expert curation
Taxonomy
Kingdom:Animalia
Phylum:Arthropoda
Class: Maxillopoda
Order:Calanoida
Family:Aetideidae

Description
Size (female): length 3.56 – 4.25 mm
Size (male): 3.62-3.69 mm

Female: The proportional lengths of the cephalothorax and abdomen are as 50 to 13, so that the abdomen is contained 3.85 times in the length of the anterior region of the body.The forehead is rounded and is devoid of any crest. The rostrum is well developed and is directed downwards and forwards. The posterior thoracic margin is as a rule very slightly asymmetrical and is in most cases produced backwards on both sides in a sharp point, but in a few instances this projection was absent on one side of the body. The margin on the right side of the body being rounded and that on the left pointed. A group of small needle-like spines is situated on the postero-lateral region.

The abdomen is composed of four segments. The genital segment is almost symmetrical but bears on its right side a short, blunt and straight spine or rod. The ventral genital protuberance is well marked and at the right side of the genital aperture is a sharp curved spine directed backwards. On the left side of the genital aperture is a second and much smaller spine, also directed backwards. The posterior part of the genital segent is armed on the left side with a band of spines running along the margin and there is a patch of spines in the dorso-lateral region of the right side. A similar, though smaller, patch of spines is situated on the posterior margin of the 2nd segment on the right side.

The 1st antenna reaches back to the posterior thoracic margin and consists of 23 free joints, segments 8 and 9 and 24 and 25 respectively being fused. The first segment of the antenna bears a tuft of hairs on the posterior aspect. On the 2nd segment there are two tufts of hair on the posterior aspect and three on the anterior aspect on the proximal side of the base of the proximal three setae.

In the 2nd antenna, the endopod is comparatively short, being only about one-half the length of the exopod; eight setae arise from the outer lobe and six from the inner. The exopod consists of 7 segments.
The mandible is of the usual type.

In the 1st maxilla, 12 setae arise from lobe 1; lobe 2 bears 4 long setae, of which two are thick and closely resemble the setae arising from lobe 1, and in addition, a fifth delicate seta; lobe 3 bears three setae. The basal segment bears 5 setae, endopod 1 bears 4 and endopod 2 and 3 together bear 7. The exopod bears 11 setae, which arise in two groups; that at the extreme distal end is composed of 5 setae and form the outer margin arise 6. The outer lobe bears 5 large setae and 4 smaller ones.In the 2nd maxilla the proximal part of the basal segment is much constricted. Lobe 5 bears a stout serrated spine that is comparatively short, being but little more than the length of the lobe itself.In the maxilliped the 2nd basal segment is more than twice as long as the first.

The number of setae borne on basal 1 are: lobe 1,1; lobe 2,2; lobe 3,3; and lobe 4,3. Basal 2 bears one seta about the middle of its length and 2 others at the junction of the third and fourth quarters; the proximal half of the anterior border is fringed with a row of needle-like spines.The first swimming leg consists of a two-jointed basal part in which both segments are fringed on their inner margins with long hairs; basal 2 bears the usual inner seta. The exopod consists of only two free segments, segments 1 and 2 being fused, though a trace of the line of division between them caneasily be seen. The marginal spine, corresponding to the proximal segment has been completely suppressed, so the combined segment only bears a single spine at its distal angle. The endopod consists of a single joint with a well-marked swelling on its outer margin which is fringed with long hairs; five setae are borne on the margin.

Male: The 1st antenna shows a distinct tendency towards the fusion of certain segment. Segments 8 and 9 are completely fusednand segments 11 and 12 and 18 and 19 are partially so; segments 24 and 25 are separate.
The mouth-parts are much reduced.

The 1st swimming leg possesses a three-jointed exopod, the lines of division between the segments being clearly visible; but the proximal segment bears no marginal spine.

The 2nd-4th swimming legs are as in the female. In the fifth pair of legs, the exopod of the right leg is composed of only two joints. In the right leg the 1st segment of the exopod bears a well-marked spine on its lateral border at about the junction of the proximal and middle thirds, and opposite this there is on the inner aspect a pair of small swellings. The inner aspect of the proximal third of the segment is finely etched with wavy parallel striae. The distal half of the segment is grooved, apparently for the reception of the endopod, which is curved to fit it. In the left leg the endopod reaches to the distal end of the 1st segment of the exopod, whereas in the males it is considerably shorter. The 2nd segment of the endopod bears a spinous process at its outer distal angle, and the inner proximal angle of the 3rd segment is produced in a retroverted process.



Synonym (s)
Undeuchaeta bispinosa Esterly, 1911

Common Name (s)
Economic Importance and Threats

Ecology

Biogeography


• INDIA (Record: 21/10/1911, 23/04/1924)

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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