Variable de estudio

A wide range of Centropages spp are recorded from the Indian Ocean. They are small to medium sized copepods and tend to have quite square cephalosomes. Some have the lateral corners of the posterior metasome segment ending in a spine, with a characteristic undulating edge on the section between the spine and the urosome. The males have a complex P5 with one side forming a large claw. One side of the male A1 is typically very thickened along part of its length.

Genus Centropages

Centropages calaninus (Dana, 1849)

Length: females: 1.72-2.18 mm; males: 1.80-2.06 mm.

Female: The last metasome segment is rounded. Both the female genital segment and furca are slightly asymmetric. The genital segment swells laterally in dorsal view. The anal segment is almost twice as long as urosome segment 2. A1 extends beyond furca by its last 2 segments. P5 exopodite segment 2 inner edge spine is straight and longer than exopodite segment 3. There is a notch on the proximal inner margin of exopodite segment 1.

Male: The last metasome segment is rounded. Right P5 exopodite segment 3 claw is longer than the inner extension of exopodite segment 2 and is sharply bent.

Recorded: Rodrigues, Seychelles, Madagascar, Aldabra.

Centropages calaninus: Female. A, dorsal; B, urosome dorsal; C, exopod of P5. Male. D, dorsal; E, P5. Figures B-D from Giesbrecht (1892), A, E from Mori (1937).

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Centropages elongatus Giesbrecht, 1896

Length: females: 1.50-1.90 mm; males: 1.74-2.0 mm.

Female: Last metasome segment is quite rounded; genital segment almost symmetrical. A1 passes the furca by the last 2 segments. The spine- like extensions of the exopodite segment 2 of the P5 exceed the distal end of exopodite segment 3. Notch in proximal internal part of segment 1 of P5. The furca are as long as the 2 preceding segments together.

Male: Last metasome segment quite rounded. Long external spine terminating the right exopodite; distinctive shape to end of left exopodite.

Recorded: Rodrigues, Seychelles, Zuza, Madagascar, Aldabra.

Centropages elongatus: Female. A, dorsal; B, urosome lateral; C, P5. Male. D, dorsal; E, urosome dorsal; F, P5; G, terminal segments of exopodite of P5 left; H, terminal exopodite of left P5 other side; I, geniculate A1 segments 17-21. From Grice (1962).

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Centropages furcatus (Dana, 1849)

Length: females: 1.60-1.78 mm; males: 1.55-1.65 mm.

Female: Quite transparent species. Cephalosome has a conspicuous ventral ball- like eye, obvious even in young stages. Prominent second spines between the lateral spines on the last metasome segment and the urosome. Strong spines on segments 1, 2 and 5 of the A1. P5 exopodite segment 2 inner edge spine does not reach the distal border of exopodite segment 3. No spines on genital segment. Anal segment not quite symmetrical, long, around twice the length of urosome segment 2. The furca are long and slender

Male: Posterior metasome border asymmetrical. Prominent second spines between the lateral spines on the last metasome segment and the urosome. P5 right extension on exopodite segment 2 has a rounded protrusion on the proximal portion; exopodite segment 3 claw is stout and has a spine on inner margin and 2 spines on outer margin; left exopodite segments 2 and 3 with long terminal fixed appendages. The furca are very long and slender.

Recorded: Rodrigues, Seychelles, Zuza, Madagascar, Aldabra.

Centropages furcatus: Female. A, dorsal; B, head lateral; C, urosome ventral; D, anterior A1: E, exopodite segments 2 and 3 of P5. Male. F, dorsal ; G, urosome dorsal: H, P5; I, right P5 exopodite segments 2 and 3; J, left exopodite segments 2 and 3 of P5. Figures A-E, G, I, J from Giesbrecht (1892), F, H from Mori (1937).

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Centropages gracilis (Dana, 1849)

Length: females: 1.85-2.00 mm; males: 1.81-2.04 mm.

Female: The lateral angles of the last metasome segment are rounded. The second urosome segment has lateral knobs covered in short spines. The furca is symmetrical. The A1 extends beyond the furca by about the last 5 segments. The inner marginal spine on exopodite 2 of the P5 does not reach the end of segment 3.

Male: The terminal claw of the grasping right P5 is longer than the thumb and has a pronounced triangular protrusion, absent in other species of the genus.

Recorded: Rodrigues, Seychelles, Zuza, Madagascar.

Centropages gracilis Female. A, dorsal; B, urosome ventral; C, P5. Male. D, dorsal ; E, P5. Figures A, B. D from Mori (1937), C, E from Grice (1962).

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Centropages orsinii Giesbrecht, 1889

Length: females: 1.40-1.60 mm; males: 1.25-1.30 mm.

Female: The last metasome segment corners are pointed, but not sharply. The furca are around twice as long as wide. The genital segment is symmetrical and has an offset spine on the ventral surface, which points backwards. The A1 does not have spines on segments 1, 2 and 5 and reaches the end of the furca. P5 are nearly symmetrical and the inner marginal spine on exopodite 2 is curved, is usually covered in small spines and does not reach the end of segment 3.

Male: The last metasome segment corners are weakly pointed. The terminal claw of the grasping right P5 is longer than the thumb. The terminal portion of exopodite segment 3 of the left P5 projects into a spine.

Recorded: Rodrigues, Seychelles, Madagascar.

Centropages orsinii: Female. A, dorsal; B, urosome ventral; C, P5; D, exopodite segments 2 and 3 of P5. Male. E, dorsal ; F, P5; G, left exopodite segments of P5; H, right exopodite of P5. Figures B, D, E, G, H from Giesbrecht (1892), A, C, F from Mori (1937).

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Centropages violaceus (Claus, 1863)

Length: females: 1.76-2.04 mm; males: 1.77-1.92 mm.

Female: Posterior metasome segments rounded. Genital segment moderately swollen, without seta or spines but with a patch of spinules on right side and a ventral downward facing projection. Urosome segment 2 with a centrally placed ventral protrusion. A1 without spines on proximal segments; extends beyond the furca. P5 exopodite segment 2 does not reach distal border of exopodite segment 3.

Male: Right geniculate A1 segments 15 and 16 without spines. Right P5 exopodite segment 2 bulbous, with an inner process with a narrow base, which is situated at mid-segment; exopodit e segment 3 long and s-shaped, 3 times the length of the inner process on exopodite segment 2. The second segment of the exopodite of the left P5 has 2 outer marginal appendages.

Recorded: Madagascar

Centropages violaceus:Female. A, dorsal; B, urosome ventral; C, urosome lateral; D, P5. Male. E, dorsal ; F, P5. Figures B-D from Giesbrecht (1892), A, E, F from Mori (1937).

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