Exploring the garage’s arachnofauna: first record of Psilochorus simoni (Berland, 1911) (Araneae: Pholcidae) in Madrid (Spain), with an updated discussion of its worldwide distribution

Explorando la aracnofauna del garaje: primer registro de Psilochorus simoni (Berland, 1911) (Araneae: Pholcidae) en Madrid (España), con una discusión actualizada de su distribución mundial

Javier Sánchez-Álvarez

Universidad Complutense de Madrid (UCM), Facultad de Ciencias Biológicas,
Departamento de Biodiversidad, Ecología y Evolución. C/ José Antonio Novais 12, 28040 Madrid, España

Corresponding author: javsan17@ucm.es, https://orcid.org/0009-0005-3658-5308

Pablo Olivares

Universidad Complutense de Madrid (UCM), Facultad de Ciencias Biológicas,
Departamento de Biodiversidad, Ecología y Evolución. C/ José Antonio Novais 12, 28040 Madrid, España

paboli02@ucm.es, https://orcid.org/0009-0008-9707-1185

Alexander Bladimir Cisneros-Avilés

Universidad Complutense de Madrid (UCM), Facultad de Ciencias Biológicas,
Departamento de Biodiversidad, Ecología y Evolución. C/ José Antonio Novais 12, 28040 Madrid, España

alexcisn@ucm.es, https://orcid.org/0009-0002-6717-2889

Milene Godfroid

Universidad Complutense de Madrid (UCM), Facultad de Ciencias Biológicas,
Departamento de Biodiversidad, Ecología y Evolución. C/ José Antonio Novais 12, 28040 Madrid, España

milenego@ucm.es, https://orcid.org/0009-0003-0978-9239

Laura Sanz-Sobrino

Universidad Complutense de Madrid (UCM), Facultad de Ciencias Biológicas,
Departamento de Biodiversidad, Ecología y Evolución. C/ José Antonio Novais 12, 28040 Madrid, España

lsanz.sobrino@gmail.es, https://orcid.org/0009-0002-1539-4113

Eduardo Morano

Universidad Complutense de Madrid (UCM), Facultad de Ciencias Biológicas,
Departamento de Biodiversidad, Ecología y Evolución. C/ José Antonio Novais 12, 28040 Madrid, España

emhbio@gmail.com, https://orcid.org/0000-0003-1239-8370

ABSTRACT

Urban ecosystems can harbor a surprising diversity of arthropods, including spiders that have adapted to human-modified environments. As part of a bioblitz conducted by the spider seminar at the Complutense University of Madrid, a survey was carried out in an underground parking lot to document synanthropic spider species. Among the six species recorded, Psilochorus simoni (Berland, 1911) was identified for the first time in the province of Madrid. This American-origin cellar spider is considered both troglophilic and synanthropic, and has spread across much of Europe, yet records from the Iberian Peninsula remain scarce. An updated distribution map was generated using literature records and data from BOLD and GBIF. The species’ presence in a garage, along with its limited dispersal capacity, suggests passive introduction via vehicles. These findings expand the known distribution of P. simoni in the Iberian Peninsula and suggest that other populations may be going unnoticed. Further monitoring of human-associated environments is encouraged to improve our understanding of arachnid biodiversity in cities.

Keywords: Araneae, Pholcidae, Psilochorus simoni, Synanthropic spiders, Urban biodiversity, Species distribution, Arthropod monitoring.

RESUMEN

Los ecosistemas urbanos pueden albergar una sorprendente diversidad de artrópodos, incluidas arañas que se han adaptado a entornos modificados por el ser humano. En el marco de un bioblitz realizado por el seminario de arañas de la Universidad Complutense de Madrid, se llevó a cabo un muestreo en un aparcamiento subterráneo con el objetivo de documentar especies de arañas sinantrópicas. Entre las seis especies recogidas, Psilochorus simoni (Berland, 1911) fue encontrado por primera vez para la provincia de Madrid. Esta araña de origen americano, considerada tanto troglófila como sinantrópica, se ha expandido por buena parte de Europa, si bien los registros en la península ibérica siguen siendo escasos. Presentamos un mapa de distribución actualizado a partir de registros recogidos en la literatura científica y datos obtenidos de BOLD y GBIF. Su presencia en un garaje, junto con su limitada capacidad de dispersión, sugiere una introducción pasiva a través de vehículos. Estos hallazgos amplían el rango de distribución conocido de P. simoni en la península ibérica y ponen de manifiesto la probabilidad de que otras poblaciones estén pasando desapercibidas. Se anima a incrementar el monitoreo de ambientes asociados al ser humano para mejorar nuestro conocimiento sobre la biodiversidad de arácnidos en las ciudades.

Palabras clave: Araneae, Pholcidae, Psilochorus simoni, Arañas sinantrópicas, Biodiversidad urbana, Distribución, Seguimiento de artrópodos.

Supplementary information ↓

CONTENIDO

1. INTRODUCTION

2. MATERIAL AND METHODS

3. RESULTS AND DISCUSSION

REFERENCES

1. INTRODUCTION

As part of the activities conducted in the “Seminario de Arañas” of the “Grupo de Seguimiento de la Biodiversidad” (https://www.ucm.es/segbiodiversidad/) at the Complutense University of Madrid (UCM), a bioblitz was conducted in the garage of the Faculty of Biological Sciences to identify synanthropic spiders. This initiative aimed to both familiarize students with the most common spider species coexisting with humans in urban settings such as the university campus, and to expand the existing knowledge of synanthropic arachnofauna in the area, including data on species composition and their phenological stages.

Although urban environments pose challenges for many organisms, some species, particularly those adapted to stable, low-light habitats like caves or underground spaces, find suitable conditions in cities. Troglophilic spiders are a notable example, many of which have successfully colonized human-made structures (Huber & Acurio, 2022Huber, B.A. & Acurio, A.E., 2022. Are introduced spiders displacing native species on Galápagos? Observations on pholcid spiders (Araneae: Pholcidae). Arachnology, 19 (sp1): 191-198. https://doi.org/10.13156/arac.2022.19.sp1.191). Nevertheless, despite increased attention to urban ecology and considerable research on some groups such as birds, pollinators or ants (Cabrero-Sañudo et al., 2023Cabrero-Sañudo, F.J., Alemany, D., Asenjo, Á., Cañizares, R., Carballo, M., García, A., Gil-Tapetado, D., Grzechnik, S., López-Collar, D., Mateos, E., Molina, J.A., Ortega, L., Patán, C., Quintana, J.R., & Tribaldos, C., 2023. Contribución al conocimiento del inventario de Biodiversidad del Campus Moncloa (Proyecto de Innovación nº 338). Universidad Complutense de Madrid. Available from https://hdl.handle.net/20.500.14352/92477 [accessed 28 Feb. 2005].), synanthropic spiders remain comparatively understudied, especially in Southern Europe (Fusco et al., 2024Fusco, T., Fattorini, S., Fortini, L., Ruzzier, E. & Di Giulio, A., 2024. Ground spiders (Chelicerata, Araneae) of an urban green space: intensive sampling in a protected area of Rome (Italy) reveals a high diversity and new records to the Italian territory. Biodiversity Data Journal, 12: e122896. https://doi.org/10.3897/BDJ.12.e122896).

Among the species identified during the bioblitz, Psilochorus simoni (Berland, 1911Bayram, A., Allahverdi, H., Danışman, T., Yiğit, N. & Kunt, K.B., 2008. A new genus and species record from Turkey: Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae). Turkish Journal of Arachnology, 1 (1): 91-97.) was particularly noteworthy. This troglophilic species, considered native to the Americas, is believed to have been accidentally introduced in Paris in the early 1900s (Fürst & Blandenier, 1993Fürst, P.A. & Blandenier, G., 1993. Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae): Découvertes de nouvelles stations suisses et discussion de son écologie. Bulletin de la Société neuchâteloise des Sciences naturelles, 116 (1): 76-86.). Since then, it has expanded across much of Europe (Benhadi-Marín, 2010Benhadi-Marín, J., 2010. First records of Psilochorus simoni (Berland, 1911) (Araneae: Pholcidae) in the Iberian Peninsula. Revista Ibérica de Aracnología, 18: 101-104.), though records from the Iberian Peninsula remain scarce (de Biurrun et al., 2025de Biurrun, G., Prieto, C. & Baquero, E., 2025. ArachnoMap, una herramienta para difundir el conocimiento del taxón Araneae en la Península Ibérica y Baleares. Revista Ibérica de Aracnología, 40: 2–3. Available from http://sea-entomologia.org/gia/map [accessed 28 Feb. 2025].).

This study aims to contribute new data on synanthropic spiders obtained from the bioblitz, thereby enriching the arachnological catalog of the Community of Madrid. Additionally, it provides a brief analysis of the geographic expansion of P. simoni at global, European, and Iberian scales, accompanied by an updated distribution map.

2. MATERIAL AND METHODS

Specimens were collected manually and using an entomological sweep net on February 12 and 26, 2025, between 11:20 and 11:40 AM, in the garage of the Faculty of Biological Sciences at the Complutense University of Madrid (Madrid, Spain) (40°26′55.7″ N, 03°43′36.8″ W; 638 m a.s.l.), a space with constant human activity. All specimens were preserved in 70% ethanol and deposited in the entomological collection of the Department of Biodiversity, Ecology, and Evolution. Identification was carried out using the taxonomic keys provided by Nentwig et al. (2025)Nentwig, W., Blick, T., Bosmans, R., Hänggi, A., Kropf, C. & Stäubli, A., 2025. Spiders of Europe. Version 03.2025. Available from https://www.araneae.nmbe.ch [accessed 28 Feb. 2025]..

A literature review was conducted focusing on synanthropic spider species, with special emphasis on records of P. simoni at the global, European, and Iberian levels (de Biurrun et al., 2025de Biurrun, G., Prieto, C. & Baquero, E., 2025. ArachnoMap, una herramienta para difundir el conocimiento del taxón Araneae en la Península Ibérica y Baleares. Revista Ibérica de Aracnología, 40: 2–3. Available from http://sea-entomologia.org/gia/map [accessed 28 Feb. 2025].). For the distribution map, historic records were extracted from open-access scientific literature, along with georeferenced data obtained from the Barcode of Life Data Systems (BOLD, 2025BOLD (2025). Barcode of Life Data Systems. Taxonomy browser: Psilochorus simoni. Available from https://v3.boldsystems.org/index.php/Public_SearchTerms?query=”Psilochorus%20simoni”[tax] [accessed 28 Feb. 2025].) and the Global Biodiversity Information Facility (GBIF.org, 2025GBIF.org, 2025. GBIF Occurrence Download. https://doi.org/10.15468/dl.rddk3f). All records were filtered, and only those with precise coordinates, based on collected specimens and identified by recognized experts, were included in the map. As a result, some countries where the species is known to be widespread —such as the United Kingdom (Lavery, 2019Lavery, A., 2019. A revised checklist of the spiders of Great Britain and Ireland. Arachnology, 18 (3): 196-212.
https://doi.org/10.13156/arac.2019.18.3.196)— are represented by only a few citations, due to the lack of precise coordinates given in the available literature. In this regard, we highlight the importance of providing accurate and detailed data, including coordinates, collection dates, and identification references, when reporting species occurrences.

Morphological examination and imaging were performed using a Motic® SMZ-171 stereomicroscope equipped with a Motic® Moticam S6 digital camera. Photographs were taken using Motic Images Plus 3.0 software, and image compositions were processed with Adobe® Photoshop 2022.

3. RESULTS AND DISCUSSION

The two sampling sessions yielded six synanthropic spider species (Table 1), belonging to three families. Among them, Pholcidae C. L. Koch, 1850 was by far the most abundant, representing the majority of collected individuals. Commonly known as cellar spiders, pholcids can be easily recognized by their markedly long legs in proportion to their body size (Nentwig et al., 2025Nentwig, W., Blick, T., Bosmans, R., Hänggi, A., Kropf, C. & Stäubli, A., 2025. Spiders of Europe. Version 03.2025. Available from https://www.araneae.nmbe.ch [accessed 28 Feb. 2025].). These spiders are typically sedentary, inhabiting cryptic environments such as beneath rocks, logs, and within caves. Certain species have adapted to human dwellings, where similar conditions are replicated, facilitating their global spread (Huber & Acurio, 2022Huber, B.A. & Acurio, A.E., 2022. Are introduced spiders displacing native species on Galápagos? Observations on pholcid spiders (Araneae: Pholcidae). Arachnology, 19 (sp1): 191-198. https://doi.org/10.13156/arac.2022.19.sp1.191).

In the Iberian Peninsula, the family comprises only 13 cited species (Nentwig et al., 2025Nentwig, W., Blick, T., Bosmans, R., Hänggi, A., Kropf, C. & Stäubli, A., 2025. Spiders of Europe. Version 03.2025. Available from https://www.araneae.nmbe.ch [accessed 28 Feb. 2025].), three of which are considered endemic (World Spider Catalog, 2025World Spider Catalog, 2025. World Spider Catalog. Version 26. Natural History Museum Bern. Available from http://wsc.nmbe.ch [accessed 28 Feb. 2025].). Within the Community of Madrid, five species have been recorded to date (de Biurrun et al., 2025de Biurrun, G., Prieto, C. & Baquero, E., 2025. ArachnoMap, una herramienta para difundir el conocimiento del taxón Araneae en la Península Ibérica y Baleares. Revista Ibérica de Aracnología, 40: 2–3. Available from http://sea-entomologia.org/gia/map [accessed 28 Feb. 2025].): Holocnemus caudatus (Dufour, 1820), H. hispanicus Wiehle, 1933, H. pluchei (Scopoli, 1763), Pholcus phalangioides (Fuesslin, 1775), and Spermophora senoculata (Dugès, 1836). Three of these species were detected during the present survey, along with P. simoni, which constitutes a new provincial record.

P. simoni can be easily distinguished from other Iberian pholcid species by its morphology (Huber, 1994Huber, B.A., 1994. Genital morphology, copulatory mechanism and reproductive biology in Psilochorus simoni (Berland, 1911) (Pholcidae; Araneae). Netherlands Journal of Zoology, 44: 85-99. https://doi.org/10.1163/156854294X00079; Slowick, 2009Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1; Nentwig et al., 2025Nentwig, W., Blick, T., Bosmans, R., Hänggi, A., Kropf, C. & Stäubli, A., 2025. Spiders of Europe. Version 03.2025. Available from https://www.araneae.nmbe.ch [accessed 28 Feb. 2025].). It differs from Holocnemus and Pholcus in its small size (<3 mm), a globose opisthosoma and the anterior position of the spinnerets (Fig. 1A). Unlike the similarly sized genera Spermophora and Spermophorides, P. simoni possesses a pair of median eyes between the lateral groups and a prominent median furrow on the prosoma (Fig. 1B-C). Regarding its differentiation from other species within the genus, the genitalia and male chelicerae play a fundamental role (Slowik, 2009Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1). Male individuals have a characteristic spur on the central part of the chelicerae (Fig. 1D) and, in the pedipalp, the procursus has a sinuous tip (Fig. 1E-F). In the females, the epigyne is simple, not bisected nor ridged (Fig. 1G). Since juveniles lack these structures, they are theoretically impossible to identify at species level. However, as P. simoni is currently the only species recorded on the Iberian Peninsula and adults were found in the same location and on the same date, the juveniles were assigned to this species.

Table I. Results of the bioblitz. Key for the abreviatures: (f) adult female,
(j) juvenile, (m) adult male, (sf) subadult female, (sm) subadult male.

Tabla I. Resultados del bioblitz. Clave para las abreviaturas: (f) hembra adulta,
(j) juvenil, (m) macho adulto, (sf) hembra subadulta, (sm) macho subadulto.

Family	Species	Date	Specimens
Filistatidae Ausserer, 1867	Filistata insidiatrix (Forsskål, 1775)	12/II/2025	1j
Pholcidae C. L. Koch, 1850	Holocnemus hispanicus Wiehle, 1933	12/II/2025	2f, 1j
		26/II/2025	3f, 1sf 2j
	Holocnemus pluchei (Scopoli, 1763)	12/II/2025	2m
		26/II/2025	1m, 4j
	Pholcus phalangioides (Fuesslin, 1775)	12/II/2025	2f, 2j
		26/II/2025	4f, 11j
	Psilochorus simoni (Berland, 1911Bayram, A., Allahverdi, H., Danışman, T., Yiğit, N. & Kunt, K.B., 2008. A new genus and species record from Turkey: Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae). Turkish Journal of Arachnology, 1 (1): 91-97.)	12/II/2025	1f
		26/II/2025	1f, 1m, 1sm, 1j
Theridiidae Sundevall, 1833	Steatoda grossa (C. L. Koch, 1838)	26/II/2025	1m, 3j

Figure 1. Morphological structures of P. simoni (A-G), along with photographs of a live juvenile (H-I) and a microhabitat where individuals were predominantly found (J). The depicted structures correspond to a subadult male (A), two different females (B,G; C) and a male (D-F). A) Lateral view of the body. B) Dorsal view of the prosoma. C) Frontal view of the prosoma. D) Frontal view of the chelicerae. E) Left pedipalp, prolateral. F) Left pedipalp, retrolateral. G) Ventral view of the female; epigyne. H) Juvenile individual on its irregular web. I) Zoom on the individual. J) Some briks where the species was predominantly found. Scale: 1 mm (black), 0.5 mm (grey).

Figura 1. Estructuras morfológicas de P. simoni (A-G), junto a fotografías de un juvenil vivo (H-I) y el microhábitat en el que la mayoría de los individuos fueron encontrados (J). Las estructuras representadas se corresponden con las de un macho subadulto (A), dos hembras distintas (B,G; C) y un macho (D-F). A) Vista lateral del cuerpo. B) Vista dorsal del prosoma. C) Vista frontal del prosoma. D) Vista frontal de los quelíceros. E) Pedipalpo izquierdo en vista prolateral. F) Pedipalpo izquierdo en vista retrolateral. G) Vista ventral de la hembra; epigino. H) Individuo juvenil en su telaraña irregular. I) El mismo ejemplar visto de cerca. J) Los ladrillos en los que la mayoría de ejemplares fueron encontrados. Escala: 1 mm (negro), 0.5 mm (gris).

This species was first described in the basement of the Sorbonne University in Paris by Berland (1911)Bayram, A., Allahverdi, H., Danışman, T., Yiğit, N. & Kunt, K.B., 2008. A new genus and species record from Turkey: Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae). Turkish Journal of Arachnology, 1 (1): 91-97., who suspected it to be an alien species of American origin, based on its initial classification in Physocyclus Simon, 1893Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1, a genus native to the Americas (World Spider Catalog, 2025World Spider Catalog, 2025. World Spider Catalog. Version 26. Natural History Museum Bern. Available from http://wsc.nmbe.ch [accessed 28 Feb. 2025].). Since then, P. simoni was documented throughout France and other European countries (de Dalmas, 1915de Dalmas, R., 1915. Capture à Paris d’un Physocyclus simoni femelle et description d’un Harpactocrates nouveau des Alpes maritimes. Bulletin de la Société Entomologique de France, 20 (19): 303-306. https://doi.org/10.3406/bsef.1915.25838; Bristowe, 1933Bristowe, W.S., 1933. Notes on the biology of spiders. X. British cellar spiders, with the description of a species new to Britain. Annals and Magazine of Natural History (10), 11 (64): 509-514. https://doi.org/10.1080/00222933308673680; Fürst & Blandenier, 1993), as well as in the United States (Chamberlin & Ivie, 1942), supporting its presumed American origin. Interestingly, despite this, there have been very few additional records in North America (Slowik, 2009Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1).

The species has since expanded across Europe, where, although initially thought to be restricted to urban structures, it has also been reported from caves (Kostanjšek & Ramšak, 2005Kostanjšek, R. & Ramšak, L., 2005. Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae), a new record for Slovenian fauna from Postojna Cave. Natura Sloveniae, 7 (1): 37-40. https://doi.org/10.14720/ns.7.1.37-39; Isaia et al., 2011Isaia, M., Paschetta, M., Lana, E., Pantini, P., Schönhofer, A.L., Christian, E. & Badino, G., 2011. Subterranean arachnids of the western Italian Alps. Monografie – Museo Regionale di Scienze Naturali di Torino, 47: 1-325.). Its distribution now spans additional continents, including the Middle East (Ghavami et al., 2007Ghavami, S., 2007. Spider fauna in Caspian Costal region of Iran. Pakistan Journal of Biological Sciences: PJBS, 10 (5): 682-691. https://doi.org/10.3923/pjbs.2007.682.691; Bayram et al., 2008Bayram, A., Allahverdi, H., Danışman, T., Yiğit, N. & Kunt, K.B., 2008. A new genus and species record from Turkey: Psilochorus simoni (Berland, 1911) (Araneae, Pholcidae). Turkish Journal of Arachnology, 1 (1): 91-97.) and Oceania, with records in New Zealand (Paquin et al., 2010Paquin, P., Vink, C. & Dupérré, N., 2010. Spiders of New Zealand: annotated family key & species list. Manaaki Whenua Press, Lincoln, New Zealand, 118 pp.) (Fig. 2).

Additionally, we report here a record of P. simoni from northwestern France, based on material provided by Alberto González Casarrubios. The specimen, an adult female, was collected in October 2022 inside a house in Brest (Finistère, France) (48°22′56.7″ N, 4°29′55.9″ W; 19 m a.s.l.)

In Spain, the first report of P. simoni was by Benhadi-Marín (2010)Benhadi-Marín, J., 2010. First records of Psilochorus simoni (Berland, 1911) (Araneae: Pholcidae) in the Iberian Peninsula. Revista Ibérica de Aracnología, 18: 101-104., based on specimens collected in 1984 but only identified decades later during a revision of the spider collection at the University of León. Since then, additional records have emerged from residential buildings (Benhadi-Marín & Ferrández, 2012Benhadi-Marín, J., & Ferrández, M.Á., 2012. La enrevesada historia de Psilochorus simoni, una araña recientemente encontrada en España. Quercus, 314: 42-46.; Ferrández, 2023Ferrández, M.Á., 2023. Observaciones sobre una población de Psilochorus simoni (Berland, 1911) (Araneae: Pholcidae) del norte de Burgos. Revista Ibérica de Aracnología, 42: 255-258.) and in caves in the north of the Peninsula (Fernández-Pérez et al., 2014Fernández-Pérez, J., Castro, A. & Prieto, C.E., 2014. Arañas cavernícolas (Araneae) de la región Vasco-Cantábrica: Nuevos registros y actualización del conocimiento. Revista Ibérica de Aracnología, 25: 77-91.; Fernández-Pérez & Prieto, 2023Fernández-Pérez, J. & Prieto, C.E., 2023. Nuevos datos de Araneae (excl. Troglohyphantes) para las cuevas vasco-cantábricas. Revista Ibérica de Aracnología, 42: 137-158.).

The present finding expands the known distribution of P. simoni into the central Iberian Peninsula and suggests that the species may be more widespread than currently documented, likely going unnoticed due to its small size (1.9–3.0 mm) and cryptic habits. Unlike Pholcus or Holocnemus, P. simoni does not construct extensive webs but rather small ones close to the ground (Huber, 1994Huber, B.A., 1994. Genital morphology, copulatory mechanism and reproductive biology in Psilochorus simoni (Berland, 1911) (Pholcidae; Araneae). Netherlands Journal of Zoology, 44: 85-99. https://doi.org/10.1163/156854294X00079). Consistently, individuals were observed in inconspicuous webs in floor-wall junctions and, notably, inside brick holes (Fig. 1H–J). Since the species does not rely on ballooning for dispersal (Huber, 2023Huber, B.A., 2023. Do pholcid spiders balloon?. Arachnology, 19 (6): 885-887. https://doi.org/10.13156/arac.2023.19.6.885), its occurrence in a garage suggests that it may have arrived via private vehicles. Similar patterns have been reported in other Araneae species (Chapman & Braig, 2018Chapman, M. & Braig, H.R. 2018. Spiders and car mirrors: Investigating UK spider species and their associations with the anthropogenic micro-habitat presented by modern car wing mirrors. School of Environmental & Natural Sciences, 28 pp.). Due to its small size, it could have been transported within vehicle bodywork, as it can easily fit into small gaps close to the ground.

These findings underscore the need for further exploration of urban environments, where despite their proximity to us, many species can remain undetected. The discovery of P. simoni in Madrid expands the known range of this species in the Iberian Peninsula, demonstrating the potential for further undocumented records in similar environments of the region. Continued research on synanthropic arachnids is essential for understanding their ecological roles and distribution patterns in urban ecosystems.

Figure 2. Geographical distribution of P. simoni worldwide. Black dots represent previous citations, while the two white dots are the new records presented here. For a better visualization of the local presence of the species the map was divided into geographical regions: Europe (A), the Middle East (B), the Western Coast of the United States and Mexico (C), New Zealand (D) and the Iberian Peninsula (E). References of the mapped points: Austria: Kritscher, 1970; Huber, 1994; Thaler, 2000. Belgium: Kekenbosch & Ransy, 1976; Fraiture, 1973. Bulgaria: Naumova et al., 2017; BOLD, 2025. Czechia: Rezác et al., 2021. Denmark: Brændegaard, 1966; Scharff & Gudik-Sørensen, 2006. Faroe Islands: Lissner et al., 2016. Lissner, J., Jensen, J.K., Hansen, L.J., Simonsen, W., Kelduni, R. & Nissen, K., 2016. An updated checklist of spiders (Araneae) of the Faroe Islands. Norwegian Journal of Entomology, 63 (2): 197-240.Finland: Huhta, 1972; BOLD, 2025BOLD (2025). Barcode of Life Data Systems. Taxonomy browser: Psilochorus simoni. Available from https://v3.boldsystems.org/index.php/Public_SearchTerms?query=”Psilochorus%20simoni”[tax] [accessed 28 Feb. 2025].. France: Berland, 1911; de Dalmas, 1915; Comellini, 1954; Bristowe, 1933; Ledoux, 1967; le Peru, 2011; Fernández-Pérez & Prieto, 2023. Germany: Moritz, 1973; BOLD, 2025. Greece: Bosmans et al., 2013. Bosmans, R., van Keer, J., Russell-Smith, A., Kronestedt, T., Alderweireldt, M., Bosselaers, J. & de Koninck, H., 2013. Spiders of Crete (Araneae). A catalogue of all currently known species from the Greek island of Crete. Nieuwsbrief van de Belgische Arachnologische Vereniging, 28 (supplement 1): 1-147.Hungary: Szinetár, 1992. Szinetár, C., 1992. Our new lodgers, new immigrants in the building dweller spider fauna in Hungary. Állattani Közlemények, 78: 99-108.Iran: Ghavami et al., 2007. Ghavami, S., 2007. Spider fauna in Caspian Costal region of Iran. Pakistan Journal of Biological Sciences: PJBS, 10 (5): 682-691. https://doi.org/10.3923/pjbs.2007.682.691Ireland: BOLD, 2025.BOLD (2025). Barcode of Life Data Systems. Taxonomy browser: Psilochorus simoni. Available from https://v3.boldsystems.org/index.php/Public_SearchTerms?query=”Psilochorus%20simoni”[tax] [accessed 28 Feb. 2025]. Italy: Brignoli, 1979; Caoduro et al., 1994; Isaia et al., 2007; Isaia et al., 2011. Luxembourg: Kreuels et al., 2019. Kreuels, M., Staudt, A. & Christian, S., 2019. Die Spinnenfauna von Luxemburg–eine Zusammenstellung der Nachweise aus den Jahren 1906-2018 (Arachnida: Araneae). Bulletin de la Société des naturalistes luxembourgeois, 12: 203-230.Mexico: Slowik, 2009.Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1 Netherlands: Vossen, 1983; Koomen, 1988; Prinsen, 1989; Helsdingen, 2010; Bloem & Noordijk, 2021. New Zealand: Paquin et al., 2010.Paquin, P., Vink, C. & Dupérré, N., 2010. Spiders of New Zealand: annotated family key & species list. Manaaki Whenua Press, Lincoln, New Zealand, 118 pp. North Macedonia: Komnenov, 2014. Komnenov, M., 2014. Spider fauna of the Osogovo Mt. Range, Northeastern Macedonia. Fauna Balkana, 2: 1-267Norway: Klausen, 1972. Klausen, F.E., 1972. Physocyclus simoni Berland (Araneae, Pholcidae) new to Norway. Norsk Entomologisk Tidsskrift, 19: 123-125.Poland: Dziabaszewski, 1967; Bielak-Bielecki & Rozwalka, 2007; Rozwalka et al., 2013; Rozwalka et al., 2016. Serbia: Komnenov & Pavićević, 2009. Sweden: Jonsson, 1990. Jonsson, L.J., 1990. Tre för Sverige nya spindelarter (Araneae). Entomologisk Tidskrift, 111: 83-86.Switzerland: Comellini, 1954; Fürst & Blandenier, 1993; Altherr, 2007. Slovakia: Svatoň et al., 2009. Svatoň, J., Gajdoš, P., Černecká, L., Franc, V., Korenko, S., Kovalčík, R. & Krumpálová, Z., 2009. Pavúky – Araneae.  In: Mašán. P. & Mihál, I. (Eds.). [Arachnids of the Cerová Vrchovina Highland (Arachnida: Araneae, Pseudoscorpiones, Opiliones, Acari)]: 21–123. Institute of Forest Ecology, Zvolen. [In Czech.]Slovenia: Kostanjšek & Ramšak, 2005; Čandek et al., 2013; BOLD, 2025. Spain: Benhadi-Marín, 2010; Benhadi-Marín & Ferrández, 2012; Fernández-Pérez et al., 2014; Fernández-Pérez & Prieto, 2023; Ferrández, 2023. Turkey: Bayram et al., 2008. United Kingdom: Bristowe, 1933. Bristowe, W.S., 1933. Notes on the biology of spiders. X. British cellar spiders, with the description of a species new to Britain. Annals and Magazine of Natural History (10), 11 (64): 509-514. https://doi.org/10.1080/00222933308673680United States of America: Slowik, 2009Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1.

Figura 2. Distribución geográfica global de P. simoni. Los puntos negros representan citas previas, mientras que los dos puntos blancos son los nuevos registros presentados en la presente publicación. Para una mejor visualización de la presencia de la especie a nivel local, el mapa está dividido en varias regiones: Europa (A), Oriente Medio (B), la costa oeste de Estados Unidos y México (C), Nueva Zelanda (D) y la península ibérica (E). Referencias de los puntos del mapa: Alemania: Moritz, 1973; BOLD, 2025. Austria: Kritscher, 1970; Huber, 1994; Thaler, 2000. Bélgica: Kekenbosch & Ransy, 1976; Fraiture, 1973. Bulgaria: Naumova et al., 2017; BOLD, 2025. Chequia: Rezác et al., 2021. Dinamarca: Brændegaard, 1966; Scharff & Gudik-Sørensen, 2006. Eslovaquia: Svatoň et al., 2009. Svatoň, J., Gajdoš, P., Černecká, L., Franc, V., Korenko, S., Kovalčík, R. & Krumpálová, Z., 2009. Pavúky – Araneae.  In: Mašán. P. & Mihál, I. (Eds.). [Arachnids of the Cerová Vrchovina Highland (Arachnida: Araneae, Pseudoscorpiones, Opiliones, Acari)]: 21–123. Institute of Forest Ecology, Zvolen. [In Czech.]Eslovenia: Kostanjšek & Ramšak, 2005; Čandek et al., 2013; BOLD, 2025. España: Benhadi-Marín, 2010; Benhadi-Marín & Ferrández, 2012; Fernández-Pérez et al., 2014; Fernández-Pérez & Prieto, 2023; Ferrández, 2023. Estados Unidos: Slowik, 2009. Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1Finlandia: Huhta, 1972; BOLD, 2025. Francia: Berland, 1911; de Dalmas, 1915; Comellini, 1954; Bristowe, 1933; Ledoux, 1967; le Peru, 2011le Peru, B., 2011. The spiders of Europe, a synthesis of data: Volume 1 Atypidae to Theridiidae. Mémoires de la Société Linnéenne de Lyon, 2: 1-522.; Fernández-Pérez & Prieto, 2023. Greece: Bosmans et al., 2013. Bosmans, R., van Keer, J., Russell-Smith, A., Kronestedt, T., Alderweireldt, M., Bosselaers, J. & de Koninck, H., 2013. Spiders of Crete (Araneae). A catalogue of all currently known species from the Greek island of Crete. Nieuwsbrief van de Belgische Arachnologische Vereniging, 28 (supplement 1): 1-147.Hungría: Szinetár, 1992. Szinetár, C., 1992. Our new lodgers, new immigrants in the building dweller spider fauna in Hungary. Állattani Közlemények, 78: 99-108.Irán: Ghavami et al., 2007. Ghavami, S., 2007. Spider fauna in Caspian Costal region of Iran. Pakistan Journal of Biological Sciences: PJBS, 10 (5): 682-691. https://doi.org/10.3923/pjbs.2007.682.691Irlanda: BOLD, 2025. BOLD (2025). Barcode of Life Data Systems. Taxonomy browser: Psilochorus simoni. Available from https://v3.boldsystems.org/index.php/Public_SearchTerms?query=”Psilochorus%20simoni”[tax] [accessed 28 Feb. 2025].Islas Feroe: Lissner et al., 2016.Lissner, J., Jensen, J.K., Hansen, L.J., Simonsen, W., Kelduni, R. & Nissen, K., 2016. An updated checklist of spiders (Araneae) of the Faroe Islands. Norwegian Journal of Entomology, 63 (2): 197-240. Italia: Brignoli, 1979; Caoduro et al., 1994; Isaia et al., 2007; Isaia et al., 2011. Luxemburgo: Kreuels et al., 2019. Kreuels, M., Staudt, A. & Christian, S., 2019. Die Spinnenfauna von Luxemburg–eine Zusammenstellung der Nachweise aus den Jahren 1906-2018 (Arachnida: Araneae). Bulletin de la Société des naturalistes luxembourgeois, 12: 203-230.Macedonia del Norte: Komnenov, 2014. Komnenov, M., 2014. Spider fauna of the Osogovo Mt. Range, Northeastern Macedonia. Fauna Balkana, 2: 1-267México: Slowik, 2009.Slowik, J., 2009. A review of the cellar spider genus Psilochorus Simon 1893 in America north of Mexico (Araneae: Pholcidae). Zootaxa, 2144: 1-53. https://doi.org/10.11646/zootaxa.2144.1.1 Nueva Zelanda: Paquin et al., 2010. Paquin, P., Vink, C. & Dupérré, N., 2010. Spiders of New Zealand: annotated family key & species list. Manaaki Whenua Press, Lincoln, New Zealand, 118 pp.Noruega: Klausen, 1972. Klausen, F.E., 1972. Physocyclus simoni Berland (Araneae, Pholcidae) new to Norway. Norsk Entomologisk Tidsskrift, 19: 123-125.Países Bajos: Vossen, 1983; Koomen, 1988; Prinsen, 1989; Helsdingen, 2010; Bloem & Noordijk, 2021. Polonia: Dziabaszewski, 1967; Bielak-Bielecki & Rozwalka, 2007; Rozwalka et al., 2013; Rozwalka et al., 2016. Reino Unido: Bristowe, 1933. Bristowe, W.S., 1933. Notes on the biology of spiders. X. British cellar spiders, with the description of a species new to Britain. Annals and Magazine of Natural History (10), 11 (64): 509-514. https://doi.org/10.1080/00222933308673680Serbia: Komnenov & Pavićević, 2009. Suecia: Jonsson, 1990. Jonsson, L.J., 1990. Tre för Sverige nya spindelarter (Araneae). Entomologisk Tidskrift, 111: 83-86.Suiza: Comellini, 1954; Fürst & Blandenier, 1993; Altherr, 2007. Turquía: Bayram et al., 2008.

Supplementary information ↑

Funding sources

Not applicable.

Supplementary material

Not applicable.

Data availability

Not applicable.

Acknowledgements

We are grateful to the Department of Biodiversity, Ecology and Evolution for granting us access to the necessary facilities and for their kind support throughout the development of this study. We also thank Alberto González Casarrubios for generously sharing the specimen he collected in France. We are indebted to Francisco José Cabrero Sañudo for his valuable comments on an earlier version of the manuscript, and to Ander Álvarez Subirán for his assistance in photographing the live specimens. Finally, we would like to thank the reviewers for their helpful comments.

Authorship contribution statement

JSA: Conceptualization, Investigation, Writing –original draft, Project administration, Writing – review & editing.

PO: Conceptualization, Investigation, Writing – original draft, Writing – review & editing.

ABCA: Conceptualization, Investigation, Writing – original draft, Writing – review & editing.

MG: Conceptualization, Investigation, Writing – review & editing.

LSS: Conceptualization, Investigation, Writing – review & editing.

EM: Conceptualization, Investigation, Supervision, Writing – original draft, Writing – review & editing.

Competing interests

Not applicable

Statement on the use of Artificial Intelligence

Not applicable.

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