The epibranchial organ, its innervation and its probable functioning in Heterotis niloticus (Pisces, teleostei, osteoglossidae)

  • Roland Bauchot
  • Jean-Marc Ridet
  • Monique Diagne


The high level of encephalization in Heterotis niloticus is due, in part, to a voluminous lobus vagalis, which has the form of a cauliflower and receives the fibers of a strong branch of the 10th (vagal) nerve. This vagal branch comes from a special branchial apparatus, the epibranchial organ, considered to be an air-breathing organ by some, and a microphagous apparatus by others. This organ has a spiral, snail-like form and its lumen is a blind-alley. Its study in a juvenile fish 10 cm SL shows that it has two canals: a peripheric one for water entrance and a central one for food exit. The epithelium between these two canals contains numerous gustatory buds, the innervation of which constitutes the branch of the vagal nerve. This epithelium is also very rich in mucous cells, which probably correspond to a muco-microphagous feeding apparatus. The exit canal, which receives the mucous string enriched with food particles, enters directly into the oesophagus. Striated muscles, attaching along the spiral tours of the epibranchial organ, probably serve as the motor that pumps water in and out and supplies the classical ciliary apparatus of the mucophagous feeding organs.

Key words

Vagal lobe Feeding apparatus Mucophagous organ 

References cited

  1. Bauchot, R., J.E. Randall, J.M. Ridet & M.L. Bauchot. 1989. Encephalization in tropical teleost fishes and comparison with their mode of life. J. Hirnf. 30: 245–269.Google Scholar
  2. Daget, J. 1957. Mémoires sur la biologie des poissons du Niger moyen. III. Reproduction et croissance d'Heterotis niloticus Ehrenberg. Bull. I.F.A.N. 19: 297–323.Google Scholar
  3. Daget, J. & F. d'Aubenton. 1957. Développement et morphologie du crne d'Heterotis niloticus. Bull. I.F.A.N. 19: 881–936.Google Scholar
  4. D'Aubenton, F. 1955a. Sur le rle de l'organe suprabranchial d'Heterotis niloticus Ehrenberg (Téléostéen). C.R. Acad. Sci. Paris 241: 113–114.Google Scholar
  5. D'Aubenton, F. 1955b. Etude de l'appareil branchiospinal et de l'organe suprabranchial d'Heterotis niloticus Ehrenberg, 1827. Bull. I.F.A.N. 17: 1179–1201.Google Scholar
  6. D'Aubenton, F. & J. Daget. 1961. Heterotis Ehrenberg, 1829, and Clupisudis Swainson, 1839 (Pisces): proposal to place on the official list of generic names in zoology. Bull. Zool. Nomencl. 24: 291–293.Google Scholar
  7. Greenwood, P.H. 1966. The caudal fin skeleton in osteoglossid fishes. Ann. Mag. Nat. Hist. 9: 581–597.Google Scholar
  8. Greenwood, P.H. 1971. Hyoid and ventral gill arch musculature in osteo-glossomorph fishes. Bull. Brit. Mus. (Nat. Hist.) Zool. 22: 3–55.Google Scholar
  9. Hyrtl, J. 1854. Beitrag zur Anatomie von Heterotis ehrenbergii C. V Denksch. Kaiserl. Akad. Wiss. Math. Naturw. Wien 8: 73–88.Google Scholar
  10. Kershaw, D.R. 1976. A structural and functional interpretation of the cranial anatomy in relation to the feeding of osteoglossoid fishes and a consideration of their phylogeny. Trans. Zool. Soc. London 33: 173–252.Google Scholar
  11. Marlier, G. 1938. Considerations sur les organes accessoires servant à la respiration aérienne chez les Téléostéens. Ann. Soc. Roy. Zool. Belg. 69: 163–185.Google Scholar
  12. Meunier, F.J. 1984. Structure et minéralisation des écailles de quelques Osteoglossidae (Ostéichthyens, Téléostéens). Ann. Sci. Natur., Zool. 6: 111–124.Google Scholar
  13. Nelson, G.J. 1967. Epibranchial organs in lower teleostean fishes. J. Zool. 153: 71–89.CrossRefGoogle Scholar
  14. Nelson, G.J. 1968. Gill arches of teleostean fishes of the division Osteoglossomorpha. J. Linn. Soc. (Zool.) 47: 261–277.Google Scholar
  15. Nelson, G.J. 1969. Infraorbital bones and their bearing on the phylogeny and geography of osteoglossomorph fishes. Amer. Mus. Novit. 2394: 1–37.Google Scholar
  16. Ridet, J.M. & R. Bauchot. 1990. Analyse quantitative de l'encéphale des Télëostéens: caractères évolutifs et adaptatifs de l'encéphalisation. I. Généralités et analyse globale. J. Hirnf. 31: 51–63.Google Scholar
  17. Ridewood, W.G. 1905. On the cranial osteology of the fishes of the families Osteoglossidae, Pantodontidae and Phractolaemidae. J. Linn. Soc. (Zool.) 29: 252–282.Google Scholar
  18. Rüppell, J. 1829. Beschreibung und Abbildungen mehrerer neuer Fische im Nil endeckt. Frankfurt am Main. 12pp. + 3 pl.Google Scholar
  19. Taverne, L. 1967. Le squelette caudal des Mormyriformes et des Ostéoglossomorphes. Bull. Acad. Roy. Belg. 53: 663–678.Google Scholar
  20. Taverne, L. 1974. Sur la presence d'organes cérébraux inconnus chez l'ostéoglossidé africain Heterotis (Ehrenberg) Cuvier et Valenciennes, 1846. Bull. Acad. Roy. Belg. 60: 346–349.Google Scholar
  21. Taverne, L. 1976. Quelques considérations sur I'ostéologie et la phylogenése des Téléostéens fossiles et actuels du super-ordre des Ostéoglossomorphes. Rev. Trav. Inst. Pches Marit. 40: 758–761.Google Scholar
  22. Taverne, L. 1977. Ostéologie, phylogenèse et systématique des Téléostéens fossiles et actuels du super-ordre des Ostéoglossomorphes. I. Ostéologie des genres Hiodon, Eohiodon, Lycoptera, Osteoglossum, Scleropages, Heterotis et Arapaima. Mém. Acad. Roy. Belg. 42: 1–235.Google Scholar
  23. Valenciennes, A. in Cuvier G. & A. Valenciennes 1847. Histoire naturelle des Poissons. T 19, Bertrand Ed., Paris 465–479.Google Scholar

Copyright information

© Kluwer Academic Publishers 1993

Authors and Affiliations

  • Roland Bauchot
    • 1
  • Jean-Marc Ridet
    • 1
  • Monique Diagne
    • 1
  1. 1.Laboratoire d' Anatomie comparée, case 7077Université Paris VIIParis Cedex 05France

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