Glossidium pedatum, Loos, 1899

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-

3.1. Adult: Glossidium pedatum ( Fig. 2 )

3.1.1. Taxonomic summary

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

Site of infection: Intestine.

Prevalence and mean intensity: 14%; 4.0.

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

Deposition of sequences: Sequence data obtained were deposited in GenBank: 28S LSU rDNA (OR892322); cox 1 (OR892362 –OR892364).

Additional SEM morphological characterisation: Tegument covered with spines; sharp pointed spines from ventral sucker decreasing in number and size to posterior extremity but absent at region of excretory pore. Two papillae lappet-like and 10 symmetrically arranged papillae surround the oral sucker aperture ( Fig. 2A ). Dome-shaped papillate sensory endings occur on the entire surface. Tegument anterior to the oral sucker possesses spines and dome papillae ( Fig. 2B ). Genital atrium in the anterior margin of ventral sucker, slightly dextral. Genital pore dextral of the median line close to anterior margin of ventral sucker ( Fig. 2 C-D). Protruding cirrus unarmed and tip blunt; cirrus surface smooth with posterior portion larger, shorter, laterally folded with tip blunt, enclosing bipartite seminal vesicle ( Fig. 2D ).

Systematic analysis: In the present study, both cox 1 (mtDNA) and the 28S LSU rDNA were employed to confirm the identity of specimens of G. pedatum . There being no cox 1 sequence of this genus in GenBank comparison could not be made but the sequence generated was deposited in GenBank under accession number OR892362–OR892364. For the 28S LSU rDNA the sequences of G. pedatum of the present study formed a well-supported clade with a sequence available with 100% bootstrap support ( Fig. 3 ). Specimens of G. pedatum from Mozambique (MK496888.1) and those from Kenya had 2 bp difference ( Table 1). Interestingly, the sequence of G. pedatum from Kenya also represented a clade closest to Haematoloechus sp. (MH285261.1) with 0.99 bootstrap support through BI. Herein, combining the characters reported by Dumbo et al. (2019b) and those observed in the present study, enrich the diagnosis of the genus Glossidium .

Figures

Fig. 2. Scanning electron micrographs of Glossidium pedatum. (A) Round oral sucker, (B) spine surrounding the oral sucker (C) location of the genital pore and a protruding cirrus, (D) structure of the cirrus sac (abbreviations: pl-papillae like lappet; os-oral sucker; pp-papillae; dp-dome papillae; vs-ventral sucker; gp-genital pore; c -cirrus; rp-rows of small papillae).

Fig. 3. Phylogenetic relationships of Glossidium pedatum Loos, 1899 to other members of Plagiorchioidea based on 28S rDNA. Phylogram was reconstructed using Bayesian Inference (BI) with Alloglossidium corti (Lamont, 1921) as an outgroup. Nodal values <0.90 (BI) are indicated by dashes (sequences of the present study are highlighted in bold).