Paraeuchaeta malayensis   Sewell,  1929 (Copepod)
Organism information awaits expert curation
Taxonomy
Kingdom:Animalia
Phylum:Arthropoda
Class: Maxillopoda
Order:Calanoida
Family:Euchaetidae

Description
Size (male): 5.6 mm.
Size (female): Length 7.0-7.5 mm.

Female: The proportional lengths of the cephalothorax and abdomen are as 201 to 95, so that the abdomen is contained 2.115 times in the length of the anterior region of the body. The progile of the anterior end of the cephalothorax and abdomen are as 201 to 95, so that the abdomen is contained 2.115 times in the length of the anterior region of the body.
The profile of the anterior end of the cephalothorax is curved and the rostrum is directed downwards and slightly forwards,but much more in vertical direction. The posterior thoracic margin is rounded and is provided with the usual tuft of hairs.

The 2nd and 3rd abdominal segments are armed along the posterior margin with a row of small spines and in the 3rd segment some of these in the mid-dorsal line are considerably enlarged. Segments 2, 3 and 4 are provided with tufts of hairs on their ventral surfaces.There is no extra tubercle on the left of the genital orifice in the 1st abdominal segment.The 2nd furcal seta and the accessory seta on both sides are considerably elongated.

The 1st antenna reaches back to the posterior thoracic margin.
In the 2nd antenna, basal 1 bears a row of long hairs and basal 2 carries a single seta. The exopod is longer than the endopod in the proportion of 31 to 25. The exopod consists of seven segments; segment 1 bears no seta, segment 2 has a small seta distally, segments 3 to 6 inclusive each bear a single long seta and the terminal segment has one seta about the middle of its length and a group of three at the extreme distal end.
The mandible is of the usual type.

In the 1st maxilla the masticatory lobe bears 13 setae; the basal segment appears to bear 5 setae and the endopod carries 8; the exopod has, in all, 11 setae, of these the proximal three are comparatively short but increase in length distally, then come 7 long setae and finally the distal seta is small; the distal portion of the inner border of the ramus is fringed with short hairs. The outer lobe bears 7 long and 2 short setae.

In the 2nd maxilla there is a patch of small spinules at the proximal end of the posterior margin; in the basal segments all 5 lobes bear three setae and the first and second lobes are fringed with needle-like spines on the posterior aspect. The endopod bears 5 setae.

In the maxilliped, basal 1 has a thin fringe of short hairs on the proximal part of the posterior margin; each of the lobes bears 3 setae; at the base of the 2nd lobe, there is a patch of needle-like spines along the anterior margin and another patch of needle-like hairs runs along the distal part of the 3rd lobe. On the 2nd basal segment there is a fringe of short needle-like spines along the proximal part of the anterior margin; three setae arise from the region of the anterior border near the junction of the middle and distal thirds; of these setae the middle one is , as usual, short and has a swollen basal part, the distal seta is somewhat longer and reaches back to the joint between the basal segments. A row of long hair-like spines runs along the distal part of the anterior margin. Two unequal setae arise from the extreme distal end. The endopod consists of the usual 5 segments bearing setae.
In the 1st swimming leg, basal 2 has its inner margin somewhat produced and fringed with long hairs; it bears the usual seta at the distal inner angle. In th exopod segments 1 and 2 are fused together but the line of separation is visible across the inner half of the joint. A minute spinule arises from the outer margin, corresponding to the marginal spine of segment 1. The outer border of the combined segment is moderately concave. Exopod 2 bears a slender marginal spine that does not quite reach to the base of the spine on exopod 3; there is a short comb of minute hair-like spines along the outer part of the distal border of the segment. The duct of a gland opens on the outer margin of exopod 3 and appears to be connected with a group of cells lying in the 2nd segment. The endopod is, as usual, one-jointed and the outer margin is produced in a rounded swelling that is crowned with short spines.

In the 2nd swimming leg basal 1 bears a seta on the distal part of the inner margin. Basal 2 has a plain inner border. Exopod 1 bears a short marginal spine and the inner border has a single seta and is fringed with hairs. The marginal spine on the 2nd segment is long and reaches to the tip of the proximal spine on the 3rd segment. A single seta arises from the inner margin. In the 3rd segment the proximal spine reaches half-way to the base of the 2nd spine and the 2nd spine reaches to the distal margin of the segment. The sinus at the base of the 2nd spine is deep, so that a line drawn between the base of the proximal spine and the bottom of the sinus and produced inwards cuts the inner margin well on the proximal side of the origin of the second seta.

The endopod consists of a single joint and the distal one-fourth is clad in short hairs.

The 3rd and 4th legs present no differences from other species. The terminal part of the 3rd segment of the endopod is like the endopod of the 2nd leg clad in short hairs.

Male: The cephalothorax and abdomen present the proportional lengths of 62 to 30, so that the abdomen is contained 2.066 times in the length of the anterior region of the body.

The anterior end of the body is rounded and the rostrum projects vertically downwards and there is no eminence above the rostral base. The posterior margin of the thorax is produced backwards somewhat and is rounded and in the dorso-lateral region bears a small spine-like projection.

The abdomen consists of five segments, of which the 5th is very short.
The posterior margina of segments 2, 3 and 4 are armed dorsally with coarse teeth. The 1st segment is crossed about the middle of its length by an overhanging ridge and furrow that runs transversely across the dorsal aspect and on the right side it bears a curved and thickened ridge of chitin . the 2nd furcal seta is about twice as long as the others, but the accessory seta is quite short, much shorter than the rest.

The 1st antenna reaches to at least the middle of the abdomen; it consists of only 21 separate segments, segments 8, 9 and 10 being fused together, as also are segments 12 and 13, though in the case of these latter segments traces of the line of separation between them can be detected.
The mouth-parts are somewhat reduced.

The 1st swimming leg consists of a three-jointed exopod and a single jointed endopod. The 2nd basal segment is somewhat produced internally and closely resembles the condition found in the female. Exopod 1 bears a minute external spine and the spine arising from exopod 2 is bent inwards across the posterior aspect of the third segment.

The 2nd swimming leg exhibits certain differences from the female in the development of the spines on the external margin of exopod 3. The middle marginal spine of exopod 3 is the largest, but even so it only reaches half-way to the base of the 3rd marginal spine. The marginal spines on the 1st and 2nd segments are small.




Synonym (s)
Paraeuchaeta barbata A. Scott, 1909

Common Name (s)
Economic Importance and Threats

Ecology

Biogeography


• 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 - http://www.marinespecies.org

Page last updated on:2011-03-14

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