Uteropolystomoides, Tinsley, 2017

Chaabane, Amira, Preez, Louis Du, Johnston, Gerald & Verneau, Olivier, 2022, Revision of the systematics of the Polystomoidinae (Platyhelminthes, Monogenea, Polystomatidae) with redefinition of Polystomoides Ward, 1917 and Uteropolystomoides Tinsley, 2017, Parasite (Paris, France) 29 (56), pp. 1-19 : 12

Uteropolystomoides , a valid taxon?

Uteropolystomoides , as its generic name indicates, is characterized by the possession of a uterus containing a few eggs (up to 12 eggs in the present study). This feature was not found in Polystomoides or any other chelonian polystomes which possess an oötype where a single egg is often retained. The uterus is sacciform and pre-ovarian. Based on the phylogenetic relationship of polystomes infecting anurans, it was shown that Polystoma , the most widespread polystome genus, could represent a polyphyletic group, including a subgroup of species infecting specifically Asian frogs of India, China and Japan [ 1, 44]. By investigating the morphology of these species more in depth, Chaabane et al. [ 6] found some specific characters of these taxa that were used for describing a new genus, i.e. Indopolystoma, Chaabane, Verneau & Du Preez 2019 within the Polystomatidae . On the contrary, given the phylogenetic position of Metapolystoma which is nested within Polystoma, Bentz et al. [ 2] considered that Metapolystoma might be not valid. However, based on the morphology and life cycle of the monophyletic Metapolystoma, Landman et al. [20] concluded that this genus should be kept as a valid taxon within the Polystomatidae . Although we follow a cladistic approach in general to name groups and although Uteropolystomoides is nested in the Polystomoides clade, we propose to retain Uteropolystomoides as a valid genus based on its unique morphological characteristics.