Marine Biology

, Volume 101, Issue 2, pp 195–203 | Cite as

Functional feeding morphology of the euphausiid Nyctiphanes australis

  • D. D. Dalley
  • S. McClatchie


The structure of the feeding basket, mandible and stomach armature of the krill Nyctiphanes australis (G. O. Sars, 1883) was examined by scanning electron microscope with the aim of predicting its diet. N. australis were collected during February 1986 and October 1986 to February 1987 in Otago Harbour, New Zealand (45° 50′ S; 170° 37′ E). Predictions based on the functional morphology were tested by examining stomach contents with SEM. Intersetule distances of the feeding basket (1 to 7.5 μm) are finer than in other krill species, suggesting that N. australis can efficiently collect nanoplankton-sized particles (2 to 20 μm). The mandibular edge index (0.74) matched the edge index of Meganyctiphanes norvegica. This indicates, in contrast to the fine feeding-basket setulation, that N. australis has a mandible resembling that of predominantly carnivorous krill species. The ratio of mandibular palp length to mandible width is 3.2±0.2, or relatively longer than the elongate palp thought to be indicative of herbivorous habit in Euphausia superba. The fine structure of the molar shows specialized surfaces which differ from those of other krill species. The internal armature of the stomach is heavily spinose, as is common in krill of herbivorous habit. Layers of various-shaped spines at differing densities were observed. The functional morphology suggests that N. australis is an opportunistic omnivore. The stomach contents tentatively support this prediction, containing fragments of phytoplankton and detrital material. However, stomach contents were generally amorphous, making identification of dietary components in the field difficult.


Electron Microscope Scanning Electron Microscope Phytoplankton Fine Structure Stomach Content 
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Literature cited

  1. Artiges, J. M., Pagano, M., Thiriot, A. (1978). Morphologie fonctionnelle des appendices nutritionnels de Meganyctiphanes norvegica (M. Sars, 1856) et Euphausia kroknii (Brandt, 1851) (Crustacea Euphausiacea). Archs. Zool. exp. gén. 119: 95–106Google Scholar
  2. Barkley, E. (1940). Nahrung und Filterapparat des Walkrebschens Euphausia superba Dana. Z. Fisch. (Beih.). 1: 65–156Google Scholar
  3. Boyd, C. M., Heyraud, M., Boyd, C. N. (1984). Feeding of the Antarctic krill, Euphausia superba. J. Crustacean Biol. 4 (Spec. No. 1): 123–141Google Scholar
  4. Dzik, J., Jazdzewski, K. (1978). The euphausiid species of the Antarctic region. Polskie. Archwm Hydrobiol. 25 (3): 589–605Google Scholar
  5. Hamner, W. M. (1988). Biomechanics of filter feeding in the Antarctic krill Euphausia superba. Review of past work and new observations. J. Crustacean Biol. 8: 149–164Google Scholar
  6. Hosie, G. W. (1982). Biology and production of Nyctiphanes australis G. O. Sars in the coastal waters of S. E. Tasmania. Unpublished M. Sc. thesis. University of Tasmania, HobartGoogle Scholar
  7. Ikeda, T., Nash, G. V., Thomas, P. G. (1984). An observation of discarded stomach with exoskeleton moult from Antarctic krill Euphausia superba Dana. Polar Biol. 3: 241–244Google Scholar
  8. Kittel, W., Ligowski, R. (1980). Algae found in the food of Euphausia crystallorophias (Crustacea). Pol. polar Res. (Warsaw) 1 (2–3): 129–137Google Scholar
  9. Lomakina, N. B. (1973). Euphausiids of the world ocean (Euphausiacea). In: Strelkova, A. A., Vacilenko, C. V. (eds.) Studies of the USSR. Zoological Institute of the Academy of Science, USSR, p. 5–84Google Scholar
  10. Marschall, H. P. (1985). Structural and functional analyses of the feeding appendages of krill larvae. In: Siegfried, W. R., Candy, P. R., Laws, R. M. (eds.) Antarctic nutrient cycles and food webs. Springer-Verlag, Berlin, Heidelberg, p. 346–354Google Scholar
  11. Mauchline, J. (1966). The biology of Thysanoessa raschii (M. Sars), with a comparison of its diet with that of Meganyctiphanes norvegica (M. Sars). In: Barnes, H. (ed.) Some contemporary studies in marine science. Allen & Unwin, London, p. 493–510Google Scholar
  12. Mauchline, J. (1967). Feeding appendages of the Euphausiacea (Crustacea). J. Zool. Lond. 153: 1–43Google Scholar
  13. Mauchline, J. (1980a). The biology of mysids and euphausiids. Adv. mar. Biol. 18: 1–681Google Scholar
  14. Mauchline, J. (1980b). Measurement of body length of Euphausia superba Dana (SCAR/SCOR/IABO/ACMRR. Group of specialists on living resources of the Southern ocean). Biomass Handb. Ser. 4: 1–9Google Scholar
  15. Mauchline, J., Fisher, L. R. (1969) The biology of euphausiids. Adv. mar. Biol. 7: 1–454Google Scholar
  16. McClatchie, S. (1985). Feeding behaviour in Meganyctiphanes norvegica (M. Sars) (Crustacea: Euphausiacea). J. exp. mar. Biol. Ecol. 86: 271–284Google Scholar
  17. McClatchie, S., Boyd, C. M. (1983). Morphological study of sieve efficiencies and mandibular surfaces in the Antarctic krill, Euphausia superba. Can. J. Fish. aquat. Sciences 40: 955–967Google Scholar
  18. McWhinnie, M. A., Denys, C. J. (1978). Biological studies of Antarctic krill, austral summer 1977–1978. Antarctic. J. U.S. 13 (4): 133–135Google Scholar
  19. Nemoto, T. (1966). Thysanoessa euphausiids, comparative morphology, allomorphosis and ecology. Scient. Rep. Whales Res. Inst. Tokyo 20: 109–155Google Scholar
  20. Nemoto, T. (1967). Feeding patterns of euphausiids and differentiations in their body characters. Inf. Bull. Planktol. Japan (Commemoration issue of Dr. Matsue) 157–174Google Scholar
  21. Nemoto, T. (1977). Food and feeding structures of deep sea Thysanopoda euphausiids. In: Anderson, N. R., Zahuranec, B. J. (eds.) Oceanic sound scattering prediction. Plenum Press. New York, p. 457–480Google Scholar
  22. Omori, M., Fleminger, A. (1976). Laboratory method for processing crustacean zooplankton. In: Steedman, H. F. (ed.) Zooplankton fixation and preservation. Unesco Press, Paris, p. 281–286Google Scholar
  23. Pavlov, V. Y. (1971). On the quantitative consumption of food for Euphausia superba Dana. Trud y vses. nauchno-issled. Inst. morsk. ryb. Khoz. Okeanogr. 86 (6): 42–54Google Scholar
  24. Ponomareva, L. A. (1976). Some data on the feeding ecology of Euphausiacea from far Eastern Seas. In: Filatova, Z. A., Kuznetsov, A. P. (eds.) Bottom fauna of the seas surrounding the USSR. Academy Nauk, Moscow, p. 106–111Google Scholar
  25. Price, H. J., Boyd, K. R., Boyd, C. M. (1988). Omnivorous feeding behavior of the Antarctic krill Euphausia superba. Mar. Biol. 97: 67–77Google Scholar
  26. Sars, G. O. (1885). Report on the Schizopoda collected by H. M. S. Challenger during the years 1873–76. Rep. scient. Results Voyage HMS Challenger 13 (37): 1–228Google Scholar
  27. Scotto, L. E. (1980). Studies on decapod Crustacea from the Indian river region of Florida. XIV. A method for rapid preparation of brachyuran larvae for scanning electron microscopy. Crustaceana 38: 99–101Google Scholar
  28. Suh, H.-L., Nemoto, T. (1988). Morphology of the gastric mill in ten species of euphausiids. Mar. Biol. 97: 79–85Google Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • D. D. Dalley
    • 1
  • S. McClatchie
    • 1
  1. 1.Portobello Marine LaboratoryPortobelloNew Zealand

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