Gyrodactylus magadiensis, Santos & Maina & Avenant-Oldewage, 2019

Santos, Quinton Marco Dos, Maina, John Ndegwa & Avenant-Oldewage, Annemariè, 2019, Gyrodactylus magadiensis n. sp. (Monogenea, Gyrodactylidae) parasitising the gills of Alcolapia grahami (Perciformes, Cichlidae), a fish inhabiting the extreme environment of Lake Magadi, Kenya, Parasite (Paris, France) 26 (76), pp. 1-13 : 7-8

Molecular identity of Gyrodactylus magadiensis n. sp.

All 10 specimens produced identical sequence data for the ITS fragment analysed. The amplified region was 882 bp in length, with the size of the 18S, ITS 1, 5.8S, ITS 2, and 28S rDNA fragments 24, 385, 158, 291, and 24 bp long, respectively. Alignment of the sequence to other data retrieved from GenBank produced a 1088 bp alignment, of which 636 positions were conserved, 446 variable, and 399 parsimony informative. Gyrodactylus magadiensis n. sp. was only distantly related to most other Gyrodactylus species ( Table 4), most closely to Gyrodactylus branchicus Malmberg, 1964 (23.2%) and most distantly to Gyrodactylus katamba García-Vásquez, Guzmán-Valdivieso, Razo-Mendivil, and Rubio-Godoy 2018 (25.4%). Distances of 0.45–25.4% were observed between species included in these analyses, while intraspecific distances of 0.00–1.14% were seen. The latter would suggest that taxa with more than 1.14% sequence divergence are distinct species, indicating that sequences for distinct species with less than that (in this case G. katamba and Gyrodactylus lamothei 8

Q. M. Dos Santos et al.: Parasite 2019, 26, 76 Mendoza-Palmero, Sereno-Uribe and Salgado-Maldonado, 2009, and G. branchicus and G. rarus Wagener, 1910 ) need to be revised to produce a robust criteria to identify species based on ITS rDNA. Topologies of phylogenetic analyses based on ML and BI methods produced similar results, thus a single combined tree is shown in Figure 4 . In all cases, G. magadiensis n. sp. formed a distinct, well supported linage from its congeners. Gyrodactylus magadiensis n. sp. appeared to be most closely related to a clade of G. katamba and G. lamothei in all cases.

Figures

Figure 4. Evolutionary history of Gyrodactylus magadiensis n. sp. based on Bayesian Inference approaches using ITS sequences for selected gyrodactylids. Statistical support for Bayesian inference (BI) and maximum likelihood (ML) methods indicated at branch nodes with posterior probabilities and bootstrap support indicated, respectively (ML/BI).