Conservation profile of the largest Palearctic silverfish and Europe's largest cave-adapted terrestrial insect: Squamatinia algharbica (Zygentoma, Nicoletiidae)

Squamatinia algharbica Mendes & Reboleira, 2012 is an iconic gigantic troglobiont silverfish, which was recently listed endangered in the Portuguese Red List of Invertebrates. It is endemic from caves of the Algarve, the southernmost part of Portugal - a karst area known as Barrocal. This area faces severe threats to cave biodiversity, such as pollution, groundwater overexploitation, land-use change at surface, intensive agriculture and aridity, associated with the lack of concrete protection measures for cave-adapted species. Biological prospection of caves in the Algarve karst massif (Portugal) increased the knowledge on the distribution of S. algharbica . We provide new distributional data that enlarge the area of occurrence and the first phylogeny for this species. Based on new molecular data, the genus Squamatinia appears with an isolated position within the Nicoletiidae family, highlighting Squamatinia algharbica as a biological relict with particularly high conservationist value. We assess the conservation status, evaluating the anthropogenic threats to its habitat and present the IUCN Red List profile, based on this new information.