Dactylogyrus decaspirus Guégan, Lambert & Euzet, 1988

Musilová, Na Ď A, Ehulková, Eva Ř & Gelnar, Milan, 2009, Dactylogyrids (Platyhelminthes: Monogenea) from the gills of the African carp, Labeo coubie Rüppell (Cyprinidae), from Senegal, with descriptions of three new species of Dactylogyrus and the redescription of Dactylogyrus cyclocirrus Paperna, 1973, Zootaxa 2241, pp. 47-68 : 52-53

Dactylogyrus decaspirus Guégan, Lambert & Euzet, 1988

( Figure 5 )

Synonym: Dactylogyrus cf senegalensis Paperna, 1979 ( Guégan et al. 1988) .

Type host and locality: Labeo coubie , Niger River (Bamako), Mali.

Other records: Labeo coubie , Volta Lake, Ghana ( Paperna 1979); Labeo coubie, Baoulé River (Missira), Mali ( Guégan et al. 1988).

Present record: Labeo coubie , Gambia River near the Campement du Lion (13º 01.493’N; 13º 14.491’W), Niokolo-Koba National Park, Senegal.

Site: Gill lamellae.

Type specimens: Holotype MNHN HC 262; vouchers of Dactylogyrus cf senegalensis Paperna, 1979 from Labeo coubie ( Ghana) RMCA M.T. 35.515 B-C, 35.516 C and E.

Material examined: 9 unflattened and 11 flattened specimens in GAP.

Comparative material examined: Dactylogyrus decaspirus Guégan, Lambert & Euzet, 1988 : holotype MNHN HC 262 (Tj 203) from Labeo coubie ; D. cf senegalensis Paperna, 1979: 5 vouchers RMCA M.T. 35.515 B-C, 35.516 C and E from Labeo coubie .

Material deposited: Voucher RMCA 37649; 2 vouchers MNHN HEL 92 (Th 191), 93 (Th 192).

Description: Body length 413 (328–468; n = 8); greatest width 75 (59–96; n = 9) usually near midlength. Haptor 67 (55–86; n = 9) long, 92 (71–113; n = 9) wide. Single pair of anchors (dorsal): inner length 55 (52– 57; n = 10); outer length 37 (34–38; n = 10); inner root 28 (26–30; n = 10) long; outer root with small terminal denticle on its inner side, 5 (3–6; n = 10) long; point 19 (18–20; n = 10) long. Two bars: dorsal bar 25 (24–27; n = 10) long, 4 (4–5; n = 10) wide; ventral bar 9 (9–10; n = 10) long, 2 (2–3; n = 10) wide. Hooks 7 pairs, dissimilar in size; hook lengths (n = 4): pairs I, V = 25 (24–26); pair II = 28 (28–29); pair III = 29 (29–30); pair IV = 26 (26–27); pair VI = 20 (19–20); pair VII = 21 (20–22). Needles (1 pair) located near hooks of pair V. Vagina sclerotized, coiled into many rings. Copulatory organ a coiled tube of about 10 rings; total length 36 (31–40; n = 9). Accessory piece comprising serrated rod lying within rings (basally articulated to base) and terminal lobate portion guiding distal end of copulatory tube.

Remarks: Paperna (1969) originally described Dactylogyrus senegalensis on the gills of two fish hosts Labeo senegalensis and L. coubie from Ghana. Ten years later, during his re-examination of the type specimens of D. senegalensis , he revealed dissimilarities in the lengths of anchor roots between the specimens from L. senegalensis and those from L. coubie , and proposed D. cf senegalensis from the latter host ( Paperna 1979). Subsequently, Guégan et al. (1988) described D. decaspirus from L. coubie in Mali and stated Paperna’s (1979) D. cf senegalensis as its synonym. These authors clearly differentiated D. decaspirus from D. senegalensis by the former species having 2 bars (only 1 bar in D. senegalensis ), anchor with long inner root and reduced outer root (short inner and long outer root in D. senegalensis , i.e. in conformity with Paperna’s description (1979)), and a copulatory organ with about 10 rings (only 3 rings in D. senegalensis ). Comparison of our specimens from L. coubie collected in Senegal with the holotype of D. decaspirus (MNHN HC 262, Tj 203) and vouchers of D. cf senegalensis (RMCA M.T. 35.515 B-C, 35.516 C and E) clearly supports conspecificity of these specimens. Although Paperna (1979) did not depict the ventral bar in his drawings, in accordance with the description of D. decaspirus by Guégan et al. (1988), we confirmed that the ventral bar is present in the haptor of D. cf senegalensis . Also, the differentiation of hook pairs based on their sizes corresponds well with the description of Guégan et al. (1988), i.e. pair III is larger and pair VI is smaller than the other hook pairs.

Figures

FIGURE 5. Dactylogyrus decaspirus Guégan, Lambert & Euzet, 1988. A. anchor; B. ventral bar; C. dorsal bar; D. hooks; E. needle; F. vagina; G. copulatory organ.