Eurobdelloides, Bolotov & Pešić, 2025

Genus Eurobdelloides gen. nov.

https://zoobank.org/ urn:lsid:zoobank.org:act:4FA0F90E-E973-424E-A076-0B0C971F5FA8

Type species: Batracobdelloides moogi Nesemann & Csányi, 1995 .

Diagnosis — Small leeches; two pairs of eyespots on somites III and IVa1; mid-body somites triannulate; dorsal surface smooth, without papillae; mouth pore subapical in the anterior half of the oral sucker; the vector tissue covers the oviducts and is located between the ovaries; seven pairs of crop caeca; six pairs of testisacs; male and female gonopores separated by two annuli: male gonopore on XII a1/a2, female gonopore on XII/XIII ( Nesemann and Csányi 1995; Nesemann and Neubert 1999; Bielecki 2004; Grosser and Pešić 2005; Bielecki et al. 2011).

Diagnostic remarks — Phylogenetically, the new genus represents a separate lineage, which is distant from the Batracobdelloides clade, including its type species, B. tricarinatus (Blanchard, 1897) . Morphologically, it could be distinguished from Batracobdelloides by a combination of the following characters: smooth dorsum (vs dorsum with longitudinal series of papillae and tubercles); two pairs of eyespots on somites III and IV a1 (vs two pairs of eyespots on somite III, the first pair is strongly reduced); male gonopore on XII a1/a2 and female gonopore on XII/XIII (vs XI/XII in male and XII a2/a 3 in female); the vector tissue present (vs absent); and eggs are attached to the venter (vs egg cluster is placed into a tube-like, enclosed cavity in the median section of the abdomen).

Etymology — The name of the new genus is combined from two words: ‘Euro’ (reference to its range restricted to Europe) and ‘bdelloides’ (reference to the former generic placement of this clade in the genus Batracobdelloides ).

Host — Freshwater snails Planorbarius corneus (Linnaeus, 1758) (preferred host) and Bithynia transsilvanica (Bielz, 1853) (occasional host) ( Nesemann and Neubert 1999).

Distribution — Austria, Greece, Hungary, Italy, Lithuania, Montenegro, Serbia, Slovakia, and Poland ( Nesemann and Neubert 1999; Bielecki et al. 2000; Grosser and Pešić 2005; Zettler and Daunys 2007; Juhász et al. 2008; Koperski 2010; Csabai et al. 2015; Marinković et al. 2021; Jueg and Zettler 2022).

Comments — The presence of the vector tissue in Eurobdelloides is a unique feature among the Glossiphoniidae , because this trait is characteristic for other families such as the Piscicolidae and Acanthobdellidae ( Bielecki 2004; Bielecki et al. 2011). In fish leeches, the presence or lack of the vector tissue is a diagnostic feature of genus- and tribe-group taxa ( Bielecki 2004). Salivary glands of Eurobdelloides are still undescribed.