The recent expansion of Chilean recluse Loxosceles laeta (Nicolet) (Arachnida: Araneae) in Southern Patagonia

: e recent expansion of the Chilean recluse Loxosceles laeta (Nicolet, 1849) in southern Patagonia is commented and discussed in the light of current global change. New records are provided from both Región de Aysén and Región de Magallanes. In addition, Isla Dawson in Magallanes is the southernmost record for a sicariid spider in South America. Identiﬁcation tips for health providers are included.

In Chile, Loxosceles laeta (Nicolet, 1849) is the most medically important species in this genus (Taucare-Ríos, 2012).It has been cited in all Chilean regions except Aysén.In Patagonia (Chile-Argentina) this species has experienced a recent expansion towards the south, which was not expected (Canals et al., 2016).e purpose of this contribution is to report the presence of L. laeta in Aysén as well as discuss its recent expansion in Southern Patagonia.
Records were obtained from specimens received for identification at Secretaría Regional Ministerial (SEREMI) de Salud, Aysén as well as collections made by the authors and specimens received for identification at Instituto de la Patagonia, Magallanes and citizen science platform ¨Insectos y Arácnidos de importancia médica y sanitaria en Patagonia¨.Identifications were made following Brescovit et al. (2017) andCarvajal &Faúndez (2017).e map was developed with Photoscape®.Photos were taken with a camera adapted to a stereomicroscope.Table I.Annual frequency of Loxosceles laeta reports in Chilean southern Patagonia.

Aysén Region
Up to 2017, considering the recent revision of Chilean Loxosceles and faunistics reports from Magallanes (Brescovit et al., 2017;Carvajal & Faúndez, 2017), L. laeta was absent in the Aysén Region.Even if it was recorded previously in Magallanes which is far southern than Aysén, it is not obvious to assume that the species is present in the distributional gap by two main reasons.First, most of the trade and human movement from and to Magallanes with the rest of Chile are either by airplane or ship.us, some invasive species, especially arthropods, may reach Magallanes but not Aysén (Faúndez & Carvajal, 2014).Second, records from Magallanes are all from Punta Arenas and neighboring localities, which are east of the Andes mountains, contrary to the majority of Chile.However, these Magellanic localities are contiguous with Argentinean Patagonia.erefore, species can passively reach Magallanes from Argentina, without extending to any Chilean Patagonian Region.
In Aysén, as well as Magallanes, we have recorded some isolated specimens in urban areas, indoors, since 2010, with no indication of naturalized populations.However, since 2016 the number and frequency of reports increased (Table I), having at least monthly records.From 2019 to early 2020 (Table I), several specimens have been collected from indoors of buildings and homes, including two females, one male and several immatures from Coyhaique.Additionally, three adult females have been recorded in 2019 from Puerto Ibañez from citizen science.
Four voucher specimens remain in the collection of the SEREMI de Salud Aysén (one male, one female, and two juveniles) and two males and one female at Instituto de la Patagonia collection.With these records, the current presence and naturalization of L. laeta in Aysén region is confirmed.is species can be recognized by the following combination of characters: six eyes disposed in pairs forming a triangle in frontal view; cephalothorax with a distinct design with a violin shape, sometimes diffuse in specimens; abdomen lacking any protuberances.In addition, specific identity must be confirmed by examination of genitalia, especially male pedipalp (Fig. 1)  In Magallanes, aer its presence was confirmed (Carvajal & Faúndez, 2017), we received periodical records confirming its establishment.At this point, it is one of the less common spiders in homes in the region, but the situation may change over time.Additionally, we received specimens from an infestation at Puerto Harris (53º49'S; 70º27'W), Isla Dawson, Tierra del Fuego Archipelago (Chilean part), becoming the first record for this species in Tierra del Fuego, as well as the southernmost record for a sicariid spider in the continent (Fig. 2).