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On the genus Dinobothrium van Beneden (Cestoda), with a description of two new species from sharks, and a note on Monorygma sp. from the electric ray

Published online by Cambridge University Press:  06 April 2009

Nora G. Sproston
Affiliation:
From the Marine Biological Laboratory, Plymouth

Extract

A new species of the giant phyllobothriid genus Dinobothrium (D. keilini n.sp.) is described from the blue shark (Carcharinus glaucus); it is compared with D. planum Linton, found for the first time from British waters, in the basking shark (Cetorhinus maximus), and the structure of both is discussed in relation to that of the genotype, D. septaria van Beneden. A fourth species, D. paciferum n.sp., also from the basking shark, is described, and though only a tenth the size of the other species, it shares most of their diagnostic scolex characters. It has eight true suckers above the four pendent bothria: in D. planum there are four true suckers and four pseudo-suckers, while in D. keilini there are only four true suckers, and D. septaria is said to have four pseudo-suckers alone. The nomenclature of the older species is revised, and the genus redefined.

Attention is directed to the adaptations in these large cestodes which facilitate interchange with the substratum: the development of lateral furrows through which the main excretory canals open to the exterior. There is also a ventral furrow, which in the nascent segments is an open cleft: this accommodates the growing uterus and permits a protracted gravid phase of the proglottides in situ. The effect is of five longitudinal hinges, which allow of considerable lateral expansion of the thick-walled strobilus. The smaller D. paciferum lacks these modifications, and the cylindrical segments are apparently detached in the gravid state. An explanation is offered for the conflicting accounts of the lateral extent of the vitellaria in this genus: there is a lateral contraction of the ventral vitelline reticulum as the ovarian phase waxes. In D. paciferum the vitellaria completely encircle the proglottis at the inception of the ovarian phase.

Notes are given on the selachiàn hosts examined, their food and the other parasites present. The relationships of Dinobothrium to other phyllobothriid genera and to Tetrabothrius are discussed.

In one electric ray, Torpedo nobiliana, a single immature strobilus of another kind of phyllobothriid was found; it is probably a new species of Monorygma, though it has slight resemblances to Calyptrobothrium—a genus characteristic of electric rays. The boat-shaped bothria are held at an angle from the scolex by contractile buttress-like wings, and at their proximal end there is a relatively large and complex sucker. Affinities with related genera are discussed and the nomenclature of Monorygma angusta (Linton) is emended.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1948

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References

REFERENCES

Baylis, H. A. (1926). J. Linn. Soc. (Zool.), 36, 161.CrossRefGoogle Scholar
van Beneden, P.J. (1871). Mém. Acad. Roy. Belg. 38, (4).Google Scholar
van Beneden, P. J. (1889). Bull. Acad. Roy. Belg. Sér. 3, 17, 68.Google Scholar
Dollfus, R. P. (1936). (In Joyeux, C. & Baer, J. G. 1936.) Cestodes des invertébrés marins et thalassoides, pp. 509–39.Google Scholar
Fage, L. (1923). Bull. Soc. zool. Fr. 48, 280.Google Scholar
Hart, J. F. (1936). Trans. Amer. Micr. Soc. 55, 488.Google Scholar
Joyeux, C. & Baer, J. G. (1936). Cestodes. Faune de France, 30, 1613.Google Scholar
Lebour, M. V. (1917). J. Mar. Biol. Ass. U.K. 11, 201.CrossRefGoogle Scholar
Legendre, R. (1923). Bull. Soc. zool. Fr. 48, 257.Google Scholar
Linton, E. (1889). Rep. U.S. Fish Comm. for 1886, 14, 453.Google Scholar
Linton, E. (1897). Proc. U.S. Nat. Mus. 19, 787.CrossRefGoogle Scholar
Linton, E. (1907). Proc. U.S. Nat. Mus. 32, 275.CrossRefGoogle Scholar
Linton, E. (1922). Proc. U.S. Nat. Mus. 60 (Art. 6).CrossRefGoogle Scholar
Linton, E. (1924). Proc. U.S. Nat. Mus. 64 (Art. 21).CrossRefGoogle Scholar
Linton, E. (1927). Proc. U.S. Nat. Mus. 70 (Art. 7).CrossRefGoogle Scholar
Lönnberg, E. (1892). Kgl. Sv. Vet.-Akad. Handl. 24, 28 pp.Google Scholar
Lönnberg, E. (1898). Bergens Mus. Aarb. no. 4, 23 pp.Google Scholar
Marshall, S. M., Nicholls, A. G. & Orr, A. P. (1934). J. Mar. Biol. Ass. U.K. 19, 793.CrossRefGoogle Scholar
Masi, L. (1912). Boll. Soc. zool. Ital. ser. 3, 1, 323.Google Scholar
Meggitt, F. J. (1924). The Cestodes of Mammals. 282 pp. London.Google Scholar
Mola, P. (1906). Ann. Mus. Zool. Univ. Napoli (n.s.), 2, (6), 1.Google Scholar
Nybelin, O. (1914). Zool. Bidr. Uppsala, 3, 225.Google Scholar
Rees, G. (1946). Parasitology, 37, 163.CrossRefGoogle Scholar
Scott, A. (1929). 37th Ann. Rep. Lane. Sea Fish. Lab. (for 1928), p. 81.Google Scholar
Scott, Th. (1909). 26th Ann. Rep. Fish. Bd Scotl. (for 1908), Pt. iii, pp. 84–5.Google Scholar
Southwell, T. (1925). A Monograph on the Tetra-phyllidea, with notes on Related Cestodes. Pp. ixv + 1368. Liverpool.Google Scholar
Woodland, W. N. F. (1927 a). J. Parasitol. 13, 231.CrossRefGoogle Scholar
Woodland, W. N. F. (1927 b). Proc. Zool. Soc. Lond. Pt. 2, 1927, 519.CrossRefGoogle Scholar
Yamaguti, S. (1934). Jap. J. Zool. 6, 1.Google Scholar
Yoshida, S. (1917). Parasitology, 9, 560.CrossRefGoogle Scholar