Paracalanus indicus
Wolfenden, 1905
Download a factsheet for Paracalanus indicus (PDF 485KB)
Taxonomy
| Phylum | Arthropoda |
| Subphylum | Crustacea |
| Class | Maxillopoda |
| Subclass | Copepoda |
| Order | Calanoida |
| Family | Paracalanidae |
| Genus | Paracalanus |
| Species | indicus |
Size
- Male: 0.85-1.02 mm.
- Female: 0.85-0.95 mm.
Distinguishing characteristics
- Small oval copepods
- Cephalosome fused with first pedigerous somite
- A1 extends beyond prosome
- Rostrum composed of 2 fine filaments
- Posterior prosome segments rounded
- Exopodites of P3 and P4 with serrated outside margin
- P4 exopod segment 3 with a spine which is closer to the end of the segment than the start
- Small P5, which is slender, short, uniramous, symmetrical and 2-segmented
- Genital somite and caudal rami symmetrical
Male
- A1 extends to about the distal border of urosome somite 2
- P5 uniramous, asymmetrical, with 5 segments on left and 2 on right. P5 extends beyond posterior border of urosome somite 3, right leg extends beyond distal border of left leg segment 2
- Anal somite longer than urosome somite 4
- Caudal rami 2x as long as wide
Female
- Urosome 4-segmented
- Short genital somite
- P5 distal segment cylindrical , terminal spine longer than its joint, outer distal spine short, about ¼ length of terminal segment
- Genital somite widest anteriorly in dorsal view
- Caudal rami 2x as long as wide with short inner seta
- A1 extends just beyond the anal somite, all segments separate
(Boltovskoy 1999, Taw 1978)
Distribution
- Epipelagic
- Coastal
- Widespread in tropical and subtropical waters of the Atlantic, Pacific and Indian Oceans, also found in subantarctic waters
- Common in coastal waters around Australia including Tasmania
Ecology
-
Suspension feeders
-
Common prey for planktivorous fish in shallow estuaries
-
Not tolerant of high particulate loads found in shallow estuaries
-
One of several neritic species that are commonly parasitized by protists
-
Suspension feeders that cannot tolerate the high particulate loads found in some shallow estuaries, and in those cases are often out-competed by Acartia tranteri.
-
Predation rate on Paracalnus indicus by small planktivorous fish is approximately twice that of Acartia tranteri, especially in shallow waters where seagrass beds are prominent.
-
Appears that Paracalanus indicus has greater visibility and lesser ability to avoid capture than Acartia tranteri (Kimmerer and McKinnon 1987).
References
Bradford-Grieve, J. M. and Markhaseva, E.L.(1999) Copepoda. South Atlantic Zooplankton. D. Boltovskoy. Leiden, The Netherlands. Backhuys Publishers.1: 869-1098.
Bradford-Grieve, J. M. (1994) The marine fauna of New Zealand: Pelagic Copepoda: Megacalanidae, Calanidae, Paracalanidae, Mecynoceridae, Eucalanidae, Spinocalanidae, Clausocalanidae. National Institute of Water and Atmospheric Research. Wellington, New Zealand.
Conway DVP, White, R.G., Hugues-Dit-Ciles, J., Gallienne, C.P. and Robins, D.B. (2003) Guide to the coastal and surface zooplankton of the south-western Indian Ocean, Vol Occasional Publications No. 15. Marine Biological Association of the United Kingdom.
Kimmerer, W.J. and McKinnon, A.D. (1990) High mortality in a copepod population caused by a parasitic dinoflagellate. Marine Biology 107: 449-452.
Taw, N. (1978) Some common components of the zooplankton of the southeastern coastal waters of Tasmania. Papers and Proceedings of the Royal Society of Tasmania 112: 69-136.