Gyrodactylus cytophagus Paperna, 1968

Rubio-Godoy, Miguel, Paladini, Giuseppe & García-Vásquez, Adriana, 2010, Gyrodactylus jarocho sp. nov. and Gyrodactylus xalapensis sp. nov. (Platyhelminthes: Monogenea) from Mexican poeciliids (Teleostei: Cyprinodontiformes), with comments on the known gyrodactylid fauna infecting poeciliid fish, Zootaxa 2509, pp. 1-29 : 17

Gyrodactylus cytophagus Paperna, 1968

( Figure 9 ; Tables 4 and 7)

Type host: Aplocheilichthys pumilis Boulenger (“Tanganyika lampeye”).

Site of infection: Skin.

Type locality: Akuse Lagoon, Adutor Lagoon and Nungua Dam, Ghana.

Type material examined: One paratype (MRAC-M.T.35.944) from A. pumilis collected from the swamps of Malaba river, Uganda.

Comments: This represents the only currently known gyrodactylid described from a poeciliid originating from the Afrotropics. Although the overall marginal hook sickle dimensions of G. cytophagus and G. j a ro c h o sp. nov. are similar, the two can be readily separated ( Figure 10 ). The sickle base of G. cytophagus is more slender, approximately rhomboid with a slightly curved underside rising towards the toe. The sickle base of G. jarocho sp. nov. by comparison is deeper, more triangular in shape with a heel that is roughly double the size of that of G. cytophagus . The shaft of G. cytophagus gently curves into the point region which terminates in line with the toe. The large curved open face of the marginal hook sickle of G. cytophagus is a marked contrast to the smaller, more closed aperture of G. xalapensis sp. nov. ( Figure 11 ). The PCA plots ( Figures 30 , 31 ) and the component loadings ( Table 5 ) suggest, however, that features of the hamuli are key to the separation of G. cytophagus from G. jarocho sp. nov.

Figures

FIGURE 30. Principal Components Analysis plot (Factor 1 vs Factor 2) of the 13 point-to-point measurements made on 45 gyrodactylids collected from a range of poeciliid hosts. Separation of the specimens is principally influenced by the hamulus total length (HTL), shaft length (HSL), point length (HPL) and aperture distance (HA) acting along Factor 1 in a negative direction, and the inner (CosIHAA) and outer (CosHAA) hamulus angles acting along Factor 1 in a positive direction. The total length (MHTL) and the shaft length (MHSL) of the marginal hook are key variables in the separation of specimens along Factor 2. The raw ellipses highlight the specimens of Gyrodactylus xalapensis sp. nov. from Heterandria bimaculata Heckel (1), and Gyrodactylus jarocho sp. nov. from Xiphophorus hellerii Heckel (2). Plot codes: a. Gyrodactylus bullatarudis Turnbull, 1956 from Poecilia mexicana Steindachner; b. G. bullatarudis from X. hellerii; c. G. j a ro c h o sp. nov. from X. hellerii; d. G. xalapensis from H. bimaculata; e. G. bullatarudis paratype from Poecilia sphenops Valenciennes; f. Gyrodactylus costaricensis Kritsky & Fritts, 1970 from P. sphenops; g. Gyrodactylus gambusiae Rogers & Wellborn, 1965 from Gambusia affinis Baird & Girard; h. Gyrodactylus pictae Cable, van Oosterhout, Barson & Harris, 2005 from Micropoecilia (= Poecilia) picta Regan; i. Gyrodactylus turnbulli Harris, 1986 from Poecilia reticulata Peters; j. Gyrodactylus poeciliae Harris & Cable, 2000 from Poecilia caucana Steindachner; k. Gyrodactylus milleri Harris & Cable, 2000 from P. caucana; l. Gyrodactylus cytophagus Paperna, 1968 from Aplocheilichthys pumilus Boulenger; m. Gyrodactylus rasini Lucký, 1973 from X. hellerii.

FIGURE 31. Principal components analysis plot (Factor 1 vs Factor 2) of Gyrodactylus bullatarudis Turnbull, 1956, Gyrodactylus cytophagus Paperna, 1968, Gyrodactylus poeciliae Harris & Cable, 2000, Gyrodactylys rasini Lucký, 1973 and Gyrodactylus xalapensis sp. nov. (13 ln - transformed variables; n = 29 specimens). The specimens of G. xalapensis sp. nov. (ellipse 1) are clearly separated from G. rasini (ellipse 2). Separation of the specimens is effected by the several hamulus variables acting along Factor 1 (total length (HTL), shaft length (HSL), point length (HPL), aperture distance (HA), distal shaft width (HDSW) and the proximal shaft width (HPSW )) and by point curve angle of the hamulus (CosHPCA), the total length (MHTL) and shaft length (MHSL) of the marginal hook acting through Factor 2. Plot codes: a. G. bullatarudis from Poecilia mexicana Steindachner; b. G. bullatarudis from Xiphophorus hellerii Heckel; d. G. xalapensis sp. nov. from Heterandria bimaculata Heckel; e. G. bullatarudis paratype from Poecilia sphenops Valenciennes; j. G. poeciliae from Poecilia caucana (Steindachner); l. G. cytophagus from Aplocheilichthys pumilus (Boulenger); m. G. rasini from X. hellerii.

FIGURES 1 – 14. A size invariant comparison of the marginal hook sickles of two new species of Gyrodactylus with the nine species previously recorded infecting poeciliids. 1. Gyrodactylus jarocho sp. nov.; 2. Gyrodactylus xalapensis sp. nov.; 3. Gyrodactylus bullatarudis Turnbull, 1956 (re-examination); 4. Overlay of G. bullatarudis with G. j a ro c h o sp. nov. (broken line); 5. Overlay of G. bullatarudis with G. xalapensis sp. nov. (broken line); 6. Gyrodactylus costaricensis Kritsky & Fritts, 1970 (re – examination); 7. Overlay of G. costaricensis with G. j a ro c h o sp. nov. (broken line); 8. Overlay of G. costaricensis with G. xalapensis sp. nov. (broken line); 9. Gyrodactylus cytophagus Paperna, 1968 (reexamination); 10. Overlay of G. cytophagus with G. ja ro c ho sp. nov. (broken line); 11. Overlay of G. cytophagus with G. xalapensis sp. nov. (broken line); 12. Gyrodactylus gambusiae Rogers & Wellborn, 1965 (re-examination); 13. Overlay of G. gambusiae with G. j a ro c h o sp. nov. (broken line); 14. Overlay of G. gambusiae with G. xalapensis sp. nov. (broken line). Scale bars = 3 µm.