On a collection of spiders (Arachnida: Araneae) from the island of Seili, with a new record for the Finnish fauna and a list of species from the island

Abstract. The results of a recent collection effort on the island of Seili (located in the Archipelago Sea, off the southwest coast of Finland in the Baltic Sea, Swedish name Själö) are reported herein. Out of 709 specimens collected at two sites using four different collection methods, 173 were adults (26 males, 147 females) and identifiable to species-level, resulting in 33 species from 13 families, including five species newly reported from the island. A male of Cheiracanthium punctorium (Villers, 1789), separately collected at a different place, represents the first record of this species in Finland and its northernmost record across its whole known range. An updated list of spider species reported from Seili (215 species from 25 families) is included as an appendix. Zusammenfassung. Die Ergebnisse einer kürzlich durchgeführten Sammelaktion auf der Insel Seili (im Schärenmeer südwestlich der finnischen Südostküste in der Ostsee gelegen, schwedischer Name Själö) werden vorgestellt. Von 709 gesammelten Exemplaren von zwei Orten, gesammelt mit verschiedenen Methoden, waren 179 adult (26 Männchen, 147 Weibchen) und auf Artniveau bestimmbar. 33 Arten aus 13 Familien, darunter fünf Erstnachweise für die Insel, wurden erfasst. Ein Männchen von Cheiracanthium punctorium (Villers, 1789), gesondert an einer anderen Stelle gesammelt, stellt den Erstnachweis für Finnland und den nördlichsten Nachweis der Art insgesamt dar. Eine aktualisierte Artenliste der Spinnen von Seili (215 Arten aus 25 Familien) wird in einem Appendix präsentiert. Abstrakti. Saaristomerellä sijaitsevan Seilin (Själö) saarella hiljattain tehdyn hämähäkkikeräyksen tulokset esitetään tässä. Kahdelta tutkimuspaikalta kerättiin neljällä eri menetelmällä 709 hämähäkkiyksilöä, joista 173 aikuista (26 koirasta ja 147 naarasta) voitiin määrittää lajitasolle. Tuloksena oli 33 lajia 13 heimosta; näistä viisi lajia on uusia Seilin saarelle. Erikseen saarelta kerätty lajin Cheiracanthium punctorium (Villers, 1789) koirasyksilö on ensimmäinen havainto lajista Suomesta ja pohjoisin löytö koko leveinneisyysalueelta. Julkaisun liitteenä on Seilin saarelta löydettyjen hämähäkkilajien luettelo (215 lajia 25 heimosta).


4) Broadleaf woodland
: Six sets of shaking ten branches inside the sweeping net, four sets of sieving detritus, five pitfall traps. The collecting was systematically randomized within the area to cover it more evenly. Sweeping nets were medium-sized standard nets. One branch was shaken per tree (pine or spruce in the heath forest, common hazel or small-leaved linden in the broadleaf woodland). A square of 0.25 m 2 was used for each set of sieving and the detritus was sieved three times through a medium-sized sieve. The pitfall traps were planted on the starting date and removed on ending date; each cup, with an upper diameter of 6.5 cm, was accompanied with a rain cover and filled with 70% denatured alcohol. All of the specimens were preserved in 70% denatured alcohol and deposited in the Zoological Museum of the University of Turku (ZMUT). The specimens were identified by the second author, using the keys and illustrations provided in Nentwig et al. (2022).
The specimen of Cheiracanthium punctorium was photographed using a Canon EOS 7D camera attached to an Olympus SZX16 stereomicroscope. Digital images were montaged using CombineZP and edited using Photoshop.

Results
A total 709 specimens were collected at the two aforementioned sites (Tab. 1), out of which 173 were adults (26 males, 147 females) and identifiable to the species-level, resulting in 33 species from 13 families (Tab. 2).
Additionally, a single specimen was collected separately and at a different location from those listed above, and represents a new record for the Finnish fauna: Description. See Almquist (2006). Collection method. This specimen was collected as a bycatch from one of several light traps for moths that had been set up for approximately 24 h. The light traps were located within one hectare in which all but one were located in a grassy heath forest, with the remaining light trap located on a nearby rocky meadow.
is the first record of the species from Finland, and its northernmost record across its known range. Medical significance. Although C. punctorium is capable of causing very painful human envenomations, often resulting in an immediate burning sensation that may last for a few hours, reports of such cases are rare and often written in local languages, for local people and local practitioners (e.g. Krumpálová 1997, Chalupský 2011, despite the widespread and expanding distribution of this species in Europe (Nentwig et al. 2013, Varl et al. 2017. In most cases only local symptoms (pain, swelling, redness) have been reported, with a mild dermonecrosis developing on very rare occasions (Vetter et al. 2006).

Conclusions
The material collected during this field course contained mainly common species. Besides C. punctorium, which is a new record for Finland, only the record of the crab spider Diaea dorsata is somewhat interesting, as it is a southern, rarely collected and apparently spreading species in Finland that was recently removed from the Red List of Finnish spiders (Koponen et al. 2013, Pajunen et al. 2019). However, apart from these two species, Cyclosa conica, Panamomops mengei, Philodromus collinus and Tetragnatha obtusa are also new for the list of Seili spiders, which now comprises 215 species from 25 families (Appendix). This, as well as the large number of common species absent from the list, shows the need for further arachnological research in Seili. The number of reported species is about a third of what is currently known for the whole of Finland (Koponen et al. 2016).