Gyrodactylus milleri Harris & Cable 2000

Gyrodactylus milleri Harris & Cable, 2000

(Figures 15, 47–52; Tables 4, 6 and 7)

Type host: Poecilia caucana Steindachner (“Cauca molly”, “piponcita”).

Site of infection: Body surface.

Type locality: La Concepción, Venezuela.

Type material examined: Holotype (BMNH 1999.4.12.1).

Comments: The original description of G. m i l l e r i by Harris & Cable (2000) was based on three specimens and contained limited morphological measurements. We provide new measurements based on the holotype deposited in the BMNH (reg. no. 1999.4.12.1), although some morphological details were not visible as the specimen was bisected and mounted on two slides. Thus, the anterior pharynx, posterior pharynx and MCO were not visible. The holotype possesses three morphologically different marginal hooks of various sizes (Figures 47–52): 10 small (S), 4 medium (M), 2 large (L) hooks (the exact measurements of the three types of marginal hooks are given in Table 6, while the mean values are presented in Table 4). This is the second known species of Gyrodactylus to have noticeably different shaped and sized marginal hooks (Figures 47–52). Previously, Gyrodactylus heterodactylus Rogers & Wellborn, 1965 collected from banded pygmy sunfish, Elassoma zonatum Jordan, was shown to possess marginal hooks of two different sizes (Rogers & Wellborn 1965).

The PCA presented in Figure 30 shows three different points (labelled k) on the scatterplot, reinforcing the idea that G. milleri marginal hooks differ markedly within the same individual (as only the holotype was available, the specimen was measured and entered in PCA analyses as three individuals with the same hamuli measurements, but different marginal hooks, using data given in Table 6).

The marginal hook sickles of G. m i l l e r i are morphologically most similar to those of G. gambusiae and G. turnbulli - large, angular, open faced sickles, both of which can be readily discriminated from G. j a ro c h o sp. nov. and G. xalapensis sp. nov. (Figures 16, 17). Figure 15 depicts and contrasts the sickles of the small marginal hooks of G. m i l l e r i, as these are the most abundant. Although the marginal hook sickles of G. milleri are morphologically similar to those of G. gambusiae and G. turnbulli, its discrimination from the other two species is possible by virtue of its three differently shaped and sized marginal hooks.

milleri Harris & Cable, 2000 (holotype BMNH 1999.4.12.1).