Macrogyrodactylus karibae Douëllou et Chishawa, 1995

Truter, Marliese, Acosta, Aline A., Weyl, Olaf L. F. & Smit, and Nico J., 2021, Novel distribution records and molecular data for species of Macrogyrodactylus Malmberg, 1957 (Monogenea: Gyrodactylidae) from Clarias gariepinus (Burchell) (Siluriformes: Clariidae) in southern Africa, Folia Parasitologica (027) 68, pp. 1-14 : 8-9

Macrogyrodactylus karibae Douëllou et Chishawa, 1995

Figs. 2G–I , 3C,D (iii); Table 6

T y p e h o s t: Clarias gariepinus (Burchell) ( Siluriformes : Clariidae ).

Ty p e l o c a l i t y: Lake Kariba, Zimbabwe.

O t h e r r e c o r d s: Clarias gariepinus . South Africa – Khalil and Mashego (1998), Olivier et al. (2009), Matla (2012); Zimbabwe – Douëllou and Chishawa (1995), Barson et al. (2008, 2010).

L o c a l i t i e s (p r e s e n t s t u d y): SouthAfrica: KuShokwe Pan and Usuthu River, Ndumo Game Reserve, KwaZulu-Natal Province; Zambia: Barotse floodplain, Zambezi River, Northwestern Province.

S i t e o f i n f e c t i o n: Skin and gills.

Vo u c h e r m a t e r i a l: Four voucher specimens deposited in, NMB P 818–821.

R e p r e s e n t a t i v e D N A s e q u e n c e s: 715–741 bp long sequence of the ITS1-5.8S-ITS2 region of the rRNA gene of two isolates. GenBank accession numbers: MZ869845 , MZ869851 . Hologenophore, NMB P 829.

S p e c i m e n s s t u d i e d: n = 8 (KuShokwe Pan, SA), n = 1 (Usuthu River, SA), n = 2 (Barotse floodplain, ZM).

I n f e c t i o n r a t e: KuShokwe Pan (SA): P = 20%, IF = 1–2; Usuthu River (SA): P = 66%, IF = 1; Barotse floodplain (ZM) P = 6%, IF = 1.

Morphological observations (measurements provided in Table 6): General morphology of the haptoral sclerites is similar to the description of Douëllou and Chishawa (1995). Marginal hook sickle blade slender and inwardly curved point, distal side slightly convex as it joins sickle blade. Base of sickle presents noticeable curvature toward anterior end of sickle, has a convex distal side with an indentation as it joins sickle blade that sharply curve inward, tapering into a sharp point that stops before proximal side of sickle base; proximal side of sickle base curved. Cirrus observed in two specimens from KuShokwe Pan ( SA) and Barotse floodplain (ZM), respectively, armed with 15 small spines and one large spine ( Fig. 2I ) .

Remarks. Macrogyrodactylus karibae can be easily distinguished from M. congolensis in having a ventral bar with short anterolateral processes and a short central arm. It can also be distinguished from M. clarii in having slender hamuli that is sharply curved into the point and root and in having a single uniform dorsal bar, wider than long (see Figs. 2G–H , 3C ). Additionally, M. karibae presents a curved proximal side of sickle base, opposed to the absence of a curved appearance in M. clarii and M. congolensis ( Fig. 2H and Fig. 3D (iii)).

Dimensions for the hamuli (total length, point, shaft and root length) for specimens in the present study from NGR (SA) and Barotse floodplain (ZM) are within the ranges reported for the same species from other localities in southern Africa ( Table 6) ( Douëllou and Chishawa 1995, Khalil and Mashego 1998, Barson et al. 2010). The size of the dorsal and ventral bars is within the size ranges previously reported. The marginal hook size and morphology are comparable to previously reported data, specimens from NGR seem to have a slightly larger marginal hook sickle than previously reported. In the description and re-evaluation of M. karibae, Douëllou and Chishawa (1995) and Khalil and Mashego (1998) did not provide details on the morphology of the marginal hooks, which are provided in the present study. Comparative measurements are presented in Table 6.

Figures

Fig. 2. Micrographs showing the morphological features of Macrogyrodactylus clarii Gussev, 1961 (A–C), M. congolensis (Prudhoe, 1957) (D–F), and M. karibae Douëllou et Chishawa, 1995 (G, H). A, D, G – hamuli complex; B, E, H – sickle of marginal hook; C, F, I – cirrus with spines.

Fig. 3. Illustrations of the hamuli of Macrogyrodactylus clarii Gussev, 1961 (A); M. congolensis (Prudhoe, 1957) (B); M. karibae Douëllou et Chishawa, 1995 (C). D – sickle of marginal hooks of M. clarii (i), M. congolensis (ii), and M. karibae (iii). Abbreviations: Ham – hamuli, Vbar – ventral bar, Dbar – dorsal bar, R1 and R2 – ventral bar rod-like sclerites.