Endangered Transsylvanian wingless groundhopper (Tetrix transsylvanica) is not extinct in Croatia and requires urgent protection

The Transsylvanian wingless groundhopper, Tetrix transsylvanica (Bazyluk et Kis, 1960) is a flightless pygmy grasshopper (Orthoptera: Tetrigidae) known only from a few fragmented localities and thus considered an endangered (EN) species in the IUCN Red List. The species consists of two subspecies, the nominal T. t. transsylvanica inhabiting the southern Carpathians in Romania, and T. transsylvanica hypsocorypha Skejo, 2014, until now known from a single locality in Slovenia (Mt Boč) and a single locality in Croatia where it was caught last time in the 1940s in Hrvatsko Zagorje (Gornja Pačetina, Trnovec). It is possible that the two subspecies represent separate species. The species has been considered extinct in Croatia. In this paper, we report the discovery of several subpopulations in Croatia, the largest one being at Siljevec on Ivanščica mountain. In addition, small subpopulations are reported on three other mountains (Strahinjčica, Medvednica and Zelinska gora), and two of them are suspected to be under threat of extinction: the subpopulation on the peak of Medvednica, Sljeme, and the subpopulation on Strahinjčica. The latter was discovered in a proximity of a quarry. The species is a (Pleistocene) relic and may be the only groundhopper endemic to Central Europe. Herewith, we appeal for its inclusion in the Ordinance on Strictly Protected Species of the Republic of Croatia, and for T. transsylvanica to be proposed as a candidate for the list of species protected through the Habitats Directive.