An inventory of the spider species of "La Mandria" Regional Natural Park (NW Italy) (Arachnida: Araneae)

We present an inventory of the spider species of the "La Mandria" Regional Natural Park (Province of Turin, Piedmont, Italy), mostly based on original data collected between 2022 and 2023. Spiders were sampled by means of pitfall traps and beating trays in the most representative habitats of the Park. Few additional species were included to the inventory from iNaturalist observations and from available literature data. We reported a total of 149 species, representing 100 genera and 28 families. Thirty-seven species are recorded for the first time in the Province of Turin and 12 are new for Piedmont. The most represented families were Lycosidae and Linyphiidae, followed by Gnaphosidae and Thomisidae. The highest number of species (60) was recorded in woodland edges, followed by mown meadows (57) and mixed broadleaved woods (50). The composition of the spider assemblages aligns with those found in similar habitats in the frame of other studies conducted in the Po Valley. Most of the species have a Palaeartic distribution, followed by Turanic-European-Mediterranean and European elements. Noteworthy, we recorded two endemic species (Nemesia pedemontana and Dysdera lantosquensis) and three alien species (Mermessus trilobatus , Erigone autumnalis and Theridula gonygaster). We also provide new taxonomic illustrations of two riparian Gnaphosidae (Gnaphosa dolosa and G. rhenana). Besides the faunistic contribution, this inventory aims at providing a basis for further studies on the conservation ecology of spiders in NW Italy.