Ditrichicorycaeus dahli
Tanaka (1957)
Download a fact sheet for Ditrichocorycaeus dahli (PDF 470KB)
Taxonomy
Phylum | Arthropoda |
Subphylum | Crustacea |
Class | Maxillopoda |
Subclass | Copepoda |
Order | Cyclopoida |
Family | Corycaeidae |
Genus | Ditrichocorycaeus |
Species | dahli |
Size
- Female: 0.85 - 1.21 mm
- Male: 0.68 - 0.99 mm
Distinguishing characters
- Peg like endopod of P4 with 2 setae and a small posterior projection
- Proportional length of urosome somites and caudal rami
- Female genital somite with pronounced dorsal lump or folding and ventral hook
- Male has oval genital somite with small ventral hook
Male
- Antenna terminal claw longer than 2nd basal joint
- Prosome 1.4 times as long as urosome
- Prosome 1.5 times as long as wide
- Apical spines on first 3 legs are straight
- Genital somite oval, 1.6 times as long as wide
- Small ventral hook on genital somite
- Caudal rami nearly 2 times as long as anal somite
- Caudal rami 8 times as long as wide
- Longest caudal rami setae longer than rami
- Urosome somites and caudal rami in the proportional lengths 50:18:32
Female
- Basal spine on antenna 2 times as long as spine on next segment
- Prosome 1.7 times as long as urosome
- Prosome points extend beyond middle of genital somite
- Apical spine of exopodite of P2 curved, with ~6 teeth on inner, anterior side
- Genital somite 1.3 times as long as wide, vaulted on dorsal surface or a folding on the distal 2/3 of somite, ventral surface flat
- Anal somite wider at proximal than distal margin
- Caudal rami divergent, 16 times as long as wide, nearly 2 times as long as anal somite
- Urosome somites and caudal rami in the proportional lengths 35:23:42
Distribution
- Epipelagic
- Coastal and oceanic
- Subtropical and tropical
- Indian and Pacific Oceans
Ecology
- Visual predators using raptorial appendages to capture small prey
- Undertakes diel vertical migration, where it spends most of its time near the bottom and ascends to the upper layers close to midnight
References
- Bradford-Grieve, J. M., E. L. Markhaseva, et al. (1999). Copepoda. South Atlantic Zooplankton. D. Boltovskoy. Leiden, The Netherlands, Backhuys Publishers. 1: 869-1098.
- Tanaka, O. (1957[1959]). On copepoda of the family Corycaeidae in Japanese waters 1957. Contx Dep Fish Kyushu Univ 3
- Chen Q.-c. & Zhang S.-z. , 1974. The pelagic copepods of the South China Sea. I.. Studia mar. sin., 9: 101-124.
- Dahl, M. (1912). Die Copepoden der Plankton-Expedition. I. Die Corycaeinen. Mit Berucksichtigung aller bekannten Arten bearb. (Ergebnisse der Plankton-Exp. Bd II. G. f. 1.). Pages: (iv + 136)
- Owens, L. Rothlisberg, P.C. 1991. Vertical migration and advection of bopyrid isopod cryptoniscid larvae in the Gulf of Carpentaria, Australia, Journla of plankton research, 13:4:279