Image Key > Copepoda > Calanoida > Calanidae > Nannocalanus minor
Nannocalanus minor
Claus 1863
Taxonomy
| Phylum |
Arthropoda |
| Subphylum |
Crustacea |
| Class |
Maxillopoda |
| Subclass |
Copepoda |
| Order |
Calanoida |
| Family |
Calanidae |
| Genus |
Nannocalanus |
Size
- Male: 1.2-1.8 mm.
- Female: 1.8-2.2 mm.
Distinguishing characteristics
- Bullet shaped.
- Readily recognized from other Calanus species by the small size.
- Cephalosome is rounded anteriorly.
- Head and 1st leg-bearing segment of the metasome are fused.
Male
- Asymmetrical 1st urosomal segment.
- Caudal rami are divergent in dorsal view.
- Longest inner edge seta on the right endopod of segment 3 of leg 5 extends to the distal border of right exopod segment 3.
Female
- As in general features.
- Pronounced ventral swelling of the genital segment.
Distribution
- Epipelagic (occurs in the upper 200 metres).
- Occurs in inshore, coastal and oceanic waters.
- Common inhabitant of tropical and subtropical waters.
- New Zealand (Jillett 1971), south-eastern Australian waters (Dakin and Colefax 1933, 1940), south-east Tasmania (Nyan Taw 1978).
- Widespread species, common to Pacific and Atlantic.
Ecology
- 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 south-eastern Australian waters.
- Life cycle includes continuous reproduction by adults and appears that increased algae in water column encourages reproduction (Ashjian and Wishner 1993).
Additional notes
- This genus is similar to Calanus spp., in which it was placed in earlier literature (Farran 1929, Bradford-Grieve 1999).
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