Nannocalanus minor
Nannocalanus minor (Claus, 1863)
Download a fact sheet for Nannocalanus minor (PDF 517KB)
Taxonomy
| Phylum | Arthropoda |
| Subphylum | Crustacea |
| Class | Maxillopoda |
| Subclass | Copepoda |
| Order | Calanoida |
| Family | Calanidae |
| Genus | Nannocalanus |
| Species | minor |
Size
- Male: 1.17-2.01 mm
- Female: 1.45-2.40 mm
Distinguishing characteristics
- Cephalosome and 1st pedigerous somite fused
- In fresh specimens edges of prosome somites may be tinged red
- Male right P5 like other swimming legs, setae on inner border of the exopod
- Male P5 left endopods without setae, left exopod with outer edge spine greatly elongated
- Right and left spermathecae fused on female
Male
- A1 reaches just past urosome
- P5 slightly asymmetric and has fine serrations on inner margin of coxa
- 1st urosome somite asymmetrical
- caudal rami rami divergent in dorsal view
Female
- A1 does not reach to end of the urosome
- Last prosome somite rounded, extending ½ way down genital somite
- Fine serrations on inner margin of P5 coxa
- Short stubby urosome, characteristically inset into prosome
- Obvious genital swelling bulging when viewed from side, with small projection low on surface
- May be confused with Calanus australis. C. australis differs as it is bigger, has 5 prosome somites, and the prosome indent is not obvious
- May be confused with Canthocalanus pauper . C. pauper has no serrations on inner margin of P5 coxa
(Boltovskoy 1999, Bradford-Grieve 1999, Taw 1978)
Distribution
- Epipelagic – mesopelagic
- Widespread in tropical, subtropical, temperate, subantarctic and Antarctic waters
- Absent from the Arctic
- Found throuout Australian oceanic and coastal waters
Ecology
- Omnivorous , feeding on fine particles
- Capable of responding very quickly when productivity in coastal waters increases; moves inshore and undergoes rapid population expansion
- Continuous reproduction, can produce 2 – 5 generations year-1 (Ashjian and Wishner 1993)
- In the north Atlantic there are two genetically distinct types: Nannocalanus minor forma major and Nannocalanus minor forma minor (Bucklin et al. 1996). It is not known which of these forms is dominant in Australian waters
References
- Ashjian, C.J. and Wishner, K.F. (1993). Temporal and spatial changes in body size and reproductive state of Nannocalanus minor (Copepoda) females across and along the Gulf Stream. Journal of Plankton Research 15: 67-98
- Boltovskoy, D. (ed.) (1999). South Atlantic Zooplankton: Backhuys Publishers, Leiden, the Netherlands.
- Bradford-Grieve, J. (1999). The marine fauna of New Zealand: Pelagic Copepoda: Arietellidae, Augaptilidae, Heterorhabdidae, Lucicutiidae, Metridinidae, Phyllopodidae, Centropagiidae, Pseudodiaptomidae, Temoridae, Candaciidae, Pontellidae, Sulcanidae, Acartiidae, Tortanidae. NIWA Biodiversity Memoirs 111, 268 pp.
- Bucklin, A., LaJeunesse, TC., Curry, E., Wallinga, J., and Garrison, K. (1996). Molecular diversity of the copepod, Nannocalanus minor: genetic evidence of species and population structure in the North Atlantic Ocean. Journal of Marine Research 54: 285-310.
- 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.
- Razouls C., de Bovée F., Kouwenberg J. et Desreumaux N., (2005-2012). - Diversity and Geographic Distribution of Marine Planktonic Copepods. Available at http://copepodes.obs-banyuls.fr/en
- 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.