Macrogyrodactylus clarii Gussev, 1961

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 : 6-7

Macrogyrodactylus clarii Gussev, 1961

Figs. 2A–C , 3A,D (i); Table 4

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

T y p e l o c a l i t y: Lake Awasa, Ethiopia.

O t h e r r e c o r d s: Clarias gariepinus : Egypt – El-Naggar and Serag (1987), El-Naggar (1993), Hagras et al. (1995, 1999), El-Naggar et al. (1997, 2001a,b, 2004a,b, 2016, 2017, 2019, 2020), El-Naggar and Cable (2007), Arafa et al. (2009, 2012), Radwan et al. (2009), El-Seify et al. (2011), Mashalay et al. (2019); Ethiopia – Gussev (1961), Beletew et al. (2016); Ghana – Paperna (1969, 1979); Kenya – Barson et al. (2010); Nigeria – Obiekezie and Ajah (1994), Eyo et al. (2015); South Africa – Khalil and Mashego (1998), Olivier et al. (2009), Madanire-Moyo et al. (2010, 2012), Matla (2012), Mahlatji (2014); Uganda – Paperna (1979); Zimbabwe – Barson et al. (2008, 2010), Madanire-Moyo and Barson (2010). Clarias anguillaris (Linnaeus) ; Nigeria – Shotter (1980).

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, 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: Twenty-three voucher specimens deposited in NMB (Coll. Nos. P 800–809, 820–822).

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: 710–753 bp long sequences of the ITS1-5.8S-ITS2 region of the rRNA gene of four isolates (GenBank accession numbers: MZ869846 , MZ869850 , MZ869847 , MZ869849 ). Hologenophores: NMB (P 824–827).

S p e c i m e n s s t u d i e d: n = 48 (KuShokwe Pan, South Africa - SA); n = 25 (Barotse floodplain, Zambia - ZM).

I n f e c t i o n r a t e: KuShokwe Pan (SA): Prevalence (P) of 80% and intensity of infection (IF) 1–12; Barotse floodplain (ZM) P = 64%, IF = 1–4.

Morphological observations (measurements provided in Table 4 ): Morphology of haptoral sclerites conform to description of Gussev (1961) and redescription of El-Naggar and Serag (1987). Individuals armed with 16 marginal hooks, two positioned in anterolateral lobes, 14 in posterior edge of haptor. Basal part of sickle has small indentation near anterior end of base, anterior end of sickle base thin, sharply rounded. Base of sickle rounded with slight curvature on distal side into slender sickle blade curving inward and tapering into a fine, sharp point that stops in line with anterior end of sickle base (see Figs. 2B , 3D (i)). Hamulus complex consisting of a pair of robust hamuli with curvature into point, sharp inward curved root, small dorsal bar consisting of two articulating sclerites, Y-shaped ventral bar with short anterolateral processes and long posterior central arm. Two narrow rod-like sclerites (R1 and R2) accompany ventral bar ( Figs. 2A–C , 3A ). Cirrus observed in 24 (SA) and 11 (ZM) specimens studied, each armed with 13–15 small spines and one large spine ( Fig. 2C ).

Remarks. The dimensions of the hamulus (total length and length of the shaft, root and point) from specimens studied from NGR (SA) and Barotse floodplain (ZM) ( Table 4 ) are similar to those of specimens from the Middle Letaba Dam (SA) and localities in Kenya and Egypt ( El-Naggar and Serag 1987, Khalil and Mashego 1998, Barson et al. 2010). Dimensions obtained for the dorsal bar in the present study do not deviate from the ranges found in other studies. Marginal hook size also conforms to previously recorded measurements. The marginal hook sickle morphology is identical to that illustrated for M. clarii specimens collected from Zimbabwe and M. clarii × Macrogyrodactylus heterobranchii from Kenya (see Barson et al. 2010). Gussev (1961) and El-Naggar and Serag (1987) reported 16 and 12 cirrus spines, with one large spine in their descriptions, respectively. Additionally, this study provides details on the morphology of the sickle, which was not described by Gussev (1961) and El-Naggar and Serag (1987). Comparative measurements are presented in Table 4 .

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.