title: Myrtoessa hyas, a new valvatiform genus and a new species of the Hydrobiidae (Caenogastropoda, Truncatelloidea) from Greece.
abstract: A new to science valvatiform hydrobiid,Myrtoessa hyasRadea,gen. n. & sp. n., from southern Greece, is described and illustrated. The new genus is a tiny gastropod thriving in a stream and is differentiated from the other known European and circum-Mediterranean valvatiform hydrobiid genera by a unique combination of the male and female genitalia features i.e. penis long, flat, blunt, with wide wrinkled proximal part and narrow distal part with a sub-terminal eversible papilla on its left side, bursa copulatrix well-developed, pyriform, fully protruding from the posterior end of the albumen gland and two seminal receptacles respectively. The new monotypic and locally endemic genus is narrowly distributed and its single known population nearby a coastal bustling village is vulnerable to anthropogenic stressors.
authors.affiliation: Department of Ecology and Systematics, Faculty of Biology, National and Kapodistrian University of Athens, 15784 Panepistimiopolis, Greece.
authors.forename: Canella
authors.initials: C
authors.lastname: Radea
authors.affiliation: Department of Ecology and Systematics, Faculty of Biology, National and Kapodistrian University of Athens, 15784 Panepistimiopolis, Greece.
authors.forename: Aristeidis
authors.initials: A
authors.lastname: Parmakelis
authors.affiliation: Department of Biology, University of Patras, 26500, Patras, Greece.
authors.forename: Sinos
authors.initials: S
authors.lastname: Giokas
keywords: Endemicity; freshwater diversity; hydrobiids; taxonomy