Systematic Parasitology

, Volume 22, Issue 3, pp 167–187 | Cite as

A revision of Oncomegas Dollfus, 1929 (Cestoda: Trypanorhyncha: Eutetrarhynchidae), the description of two new species and comments on its classification

  • Lee M. Toth
  • Ronald A. Campbell
  • Gerald D. Schmidt


Oncomegas Dollfus, 1929 is completely defined for the first time based upon a redescription of the type-species, O. wageneri (Linton, 1890) from Dasyatis centroura (Mitchill), and the description of two new species, O. paulinae from Urolophus halleri Cooper and O. australiensis from Aetobatus narinari (Euphrasen). The three species of Oncomegas are differentiated from one another by scolex ratio, basal and metabasal armatures, testis number and arrangement, number of vaginal sphincters, form of gravid uterus, position of genital pores, and form of the osmoregulatory canals.

Diagnostic characters of Oncomegas are: acraspedote scolex, two bothridia, asymmetrical tentacular basal swelling, basal armature with macrohook, typical heteroacanthous metabasal armature, prebulbar organs, elongate bulbs, retractor muscle origin at base of bulb, external seminal vesicle present, testes in two longitudinal rows or bands, seminal receptacle, lack of a postovarian testicular space, linear gravid uterus with lateral diverticula, and osmoregulatory ducts dorsal to cirrus-sac.

The combination of heteroacanthous typical tentacle armature, two bothridia lacking ciliated pits, presence of prebulbar organs, retractor muscles originating at base of bulbs and posterior ovary warrant the placement of Oncomegas in the Eutetrarhynchidae. Oncomegas is most similar to Eutetrarhynchus Pintner, 1913 in arrangement of hooks of principal rows in opposing half-spirals which abut in ‘V’-formations on both internal and external faces, presence of a basal armature and swelling, presence of an external seminal vesicle, testes confined to the intervascular medullary zone, posterior ovary and circumcortical vitelline field. Oncomegas differs from all eutetrarhynchid genera in the possession of a single macrohook in the basal armature and all except Eutetrarhynchus in the lack of a wide space between hook files 1 and (1′) of the principal rows.


Seminal Receptacle Gravid Uterus Retractor Muscle Osmoregulatory Canal Vitelline Field 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Beveridge, I. (1990) Taxonomic revision of Australian Eutetrarhynchidae Guiart (Cestoda: Trypanorhyncha). Invertebrate Taxonomy, 4, 785–845.Google Scholar
  2. Beveridge, I. & Campbell, R.A. (1987) Trimacracanthus gen. nov. (Cestoda: Trypanorhyncha: Eutetrarhynchidae), with redescriptions of T. aetobatidis (Robinson, 1959) comb. nov. and T. binuncus (Linton, 1909) comb. nov. Transactions of the Royal Society of South Australia, 111, 163–171.Google Scholar
  3. Beveridge, I. & Campbell, R.A. (1988) A review of the Tetrarhynchobothriidae Dollfus, 1969 (Cestoda: Trypanorhyncha) with descriptions of two new genera, Didymorhynchus and Zygorhynchus. Systematic Parasitology, 12, 3–29.Google Scholar
  4. Caira, J.N. & Gavarrino, M.M. (1990) Grillotia simile (Linton, 1908) n. comb. (Cestoda, Trypanorhyncha) from nurse sharks in the Florida Keys. Journal of the Helminthological Society of Washington, 57, 15–20.Google Scholar
  5. Campbell, R.A. & Carvajal, J. (1975) A revision of some trypanorhynchs from the western North Atlantic described by Edwin Linton. Journal of Parasitology, 61, 1,016–1,022.Google Scholar
  6. Carvajal, J. & Rego, A.A. (1985) Critical studies on the genus Callitetrarhynchus (Cestoda: Trypanorhyncha) with recognition of Rhynchobothrium speciosum Linton, 1897 as a valid species of the genus Callitetrarhynchus. Systematic Parasitology, 7, 161–167.Google Scholar
  7. Dollfus, R.Ph. (1929) Sur les Tétrarhynques. I. Définition des genres. Bulletin de la Société Zoologique de France, 54, 308–342.Google Scholar
  8. Dollfus, R.Ph. (1942) Etudes critiques sur les tétrarhynques du Muséum de Paris. Archives du Muséum National d'Histoire Naturelle, 19, 1–466.Google Scholar
  9. Dollfus, R.Ph. (1946) Notes diverses sur des tétrarhynques. Memoires Muséum National d'Histoire Naturelle, 22, 179–220.Google Scholar
  10. Dollfus, R.Ph. (1974) Enumération des cestodes du plancton et des Invertébrés marins. Annales de Parasitologie Humaine et Comparée, 49, 381–410.Google Scholar
  11. Linton, E.B. (1890) Notes on entozoa of marine fishes of New England, with descriptions of several new species. Part II. Annual Report of the Commissioner of Fish and Fisheries, 1887, 15, 719–899.Google Scholar
  12. Mamaev, Y.L. (1970) [Helminths of fish of the Gulf of Tong King.] In: Oshmarin, P.G. (Ed.) [Helminths of animals of south-eastern Asia.] Moscow: Nauka, 127–190 (In Russian).Google Scholar
  13. Rudolphi, C.A. (1819) Entozoorum synopsis cui accendunt mantissa duplex et indices locupletissimi. Berolini, x+811 pp.Google Scholar
  14. Schmidt, G.D. (1986) CRC handbook of tapeworm identification. Boca Raton, Florida: CRC Press, 675 pp.Google Scholar
  15. Southwell, T. (1924) Notes on some Tetrarhynchid parasites from Ceylon marine fishes. Annals of Tropical Medicine and Parasitology, 18, 459–491.Google Scholar
  16. Thatcher, V.E. (1961) Studies on the Cestoda of elasmobranch fishes of the northern Gulf of Mexico. Part I. Proceedings of the Louisiana Academy of Science, 23, 65–74.Google Scholar
  17. Wagener, G.R. (1854) Die Entwickelung der Cestoden nach eigenen Untersuchungen. Nova acta Akademiae Caesaraeae Leopoldino-Carolinae Naturae Curiosorum, 24, (Suppl.), 21–91.Google Scholar
  18. Yamaguti, S. (1934) Studies on the helminth fauna of Japan. Part 4. Cestodes of fishes. Japanese Journal of Zoology, 6, 1–112.Google Scholar
  19. Yamaguti, S. (1952) Studies on the helminth fauna of Japan. Part 49. Cestodes of fishes, II. Acta Medica Okayama, 8, 1–78.Google Scholar
  20. Yamaguti, S. (1959) Systema helminthum. Vol. II. The cestodes of vertebrates. New York: Interscience Publishers, 860 pp.Google Scholar

Copyright information

© Kluwer Academic Publishers 1992

Authors and Affiliations

  • Lee M. Toth
    • 1
  • Ronald A. Campbell
    • 1
  • Gerald D. Schmidt
    • 2
  1. 1.Department of BiologyUniversity of Massachusetts DartmouthNorth DartmouthUSA
  2. 2.Department of ZoologyUniversity of Northern ColoradoGreeleyUSA

Personalised recommendations