Tylodelphys mashonensis (Sudarikov, 1971)

Maraganga, Joan M., Rindoria, Nehemiah M., Morara, George M., Kimani, Veronica N., Wyk, Coret van, Jos, Dumbo, e C., Smit, Nico J. & Luus-Powell, Wilmien J., 2024, Tegumental topography and molecular characterisation of two trematodes (Platyhelminthes: Digenea) from Clarias gariepinus (Burchell, 1822) in Kenya, International Journal for Parasitology: Parasites and Wildlife 23, pp. 100897-100897 : 100897-

3.2. Metacercariae: Tylodelphys mashonensis ( Fig. 4 )

3.2.1. Taxonomic summary

Host: Clarias gariepinus (Burchell, 1822) ( Siluriformes , Clariidae ).

Site of infection: Vitreous humour.

Prevalence and mean intensity: 7%; 3.2.

Locality/collection date: Lake Ol’ Bolossat , Kenya, May 2022 .

Deposition of sequences: Sequence data obtained were deposited in GenBank: cox 1 (OR892362 – OR892364).

Morphological characterisation with SEM: Body elongate, wide in anterior region narrowing toward posterior extremity. Tegument without spines, corrugations in entire body. Anterior extremity comprises a subterminal well-developed oral sucker; Oral sucker spherical surrounded by dense row of papillae ( Fig. 4A ). Three (3) pairs of symmetrical papillae arranged in uniform bilateral pattern underneath rim of oral sucker. Two pseudosuckers close to oral sucker, bilaterally positioned at anterior end of the body. Tegument armed with papillae, sensory structures or non-ciliated receptors ( Fig. 4B ). Ventral sucker oval to spherical-shaped, smaller in size than oral sucker, placed midventral on body; Its rim exhibits surface corrugations arranged radially and bears 4 large papillae and other 4 small papillae ( Fig. 4C ). Tegument around ventral sucker contain many non-ciliated receptors and papillae. Holdfast organ partially covered without well recognized shape with fissure placed between ventral sucker and the posterior extremity ( Fig. 4D ).

Molecular analysis: Sequences of T. mashonensis analyzed in the present study are identical to other available sequences in GenBank (KR863378 and KR863381) ( Fig. 5 ) from the same host. The present sequences and those available in GenBank diverged by a 0–2 base pair difference ( Table 2), thus indicating that the sequences are related. The clade comprising T. mashonensis and its congeners ( T. clavata and T. excavata ) is supported by high bootstrap value meaning that they are evolutionary-related species. Unlikely the present parasite collected in a freshwater host ( C. gariepinus ), T. clavata was from an estuarine fish ( Perca fluviatilis ) and T. excavata from the anuran Pelophylax ridibundus .

Figures

Fig. 4. Scanning electron micrographs of Tylodelphys mashonensis. (A) ventral surface ultrastructure, (B) sensory papillae surrounding the oral sucker (C) ventral sucker surrounded by small and large papillae, (D) well organized holdfast organ with spines (abbreviations: ps-pseudo suckers, os-oral sucker, ho- holdfast organ, vs-ventral sucker, pp-papillae, sp-symmetrical papillae, lp- large papillae, hf-holdfast fissure).

Fig. 5. Phylogenetic relationships of Tylodelphys mashonensis (Sudarikov, 1971) to other Diplostomidae based on cox1. Phylogram was reconstructed using Bayesian Inference (BI) with Diplostomum spathaceum (Rudolphi, 1819) as an outgroup. Nodal values <0.90 (BI) are indicated by dashes (sequences of the present study are highlighted in bold).