Theridiidae  Sundevall, 1833 / Rugathodes  Archer, 1950   4 species

Rugathodes instabilis (O. Pickard-Cambridge, 1871)

Description

Prosoma light yellow-brown with dark median band, reaching from posterior end to eye region. Sternum yellowish. Chelicerae light brown, male: very long, with large conical tooth. Legs yellow-brown, unicoloured, rarely darkened on joints. Opisthosoma yellowish brown, dorsally with large brown spot, a longitudinal band, or unicoloured.

Body length male: 2.0-3.0 mm
Body length female: 2.0-3.0 mm
Additional information

In high vegetation of humid forests and meadows

Distribution
  Presence
  No data
Global distribution (WSC 2026): Europe, Russia (Europe to West Siberia)
Phenology
JanFebMarAprMayJunJulAugSepOctNovDec
 male  female
Figures
Distribution List
Austria   (Knoflach & Thaler, 1998) ||| Belgium   (Bosmans & Van Keer, 2017) ||| Bulgaria   (Naumova et al., 2021) ||| Czechia   (Růžička & Řezáč, 2022a) ||| Denmark   (Scharff & Gudik-Sørensen, 2006) ||| Estonia   (Sammet et al., 2023) ||| Finland   (Koponen et al., 2016; Pajunen & Väisänen, 2015) ||| France   (Le Peru, 2007) ||| Germany   (Blick et al., 2016) ||| Hungary   (Szinetár & Kovács, 2013) ||| Ireland   (Lavery, 2019) ||| Italy   (Isaia et al., 2025) ||| Liechtenstein   (Arnold, 2001) ||| Luxembourg   (Kreuels et al., 2019) ||| Netherlands   (van Helsdingen, 2025a) ||| Northern Ireland   (Lavery, 2019) ||| Poland   (Rozwałka & Stanska, 2008) ||| Romania   (Weiss & Petrișor, 1999) ||| Russia, Central   (Ponomarev, 2022) ||| Russia, Eastern   (Esyunin & Efimik, 1996a) ||| Russia, Southern   (no references) ||| Slovakia   (Gajdoš et al., 1999) ||| Spain   (Branco et al., 2019) ||| Sweden   (Kronestedt, 2001) ||| Switzerland   (Maurer & Hänggi, 1990) ||| Ukraine   (Polchaninova & Prokopenko, 2019) ||| United Kingdom   (Lavery, 2019) |||
References

Arnold K (2001) Beitrag zur Spinnenfauna (Arachnida, Araneae) des Fürstentums Liechtenstein. Berichte der Botanisch-Zoologischen Gesellschaft Liechtenstein-Sargans-Werdenberg 28: 211-244 pdf

Blick T, Finch O-D, Harms K H, Kiechle J, Kielhorn K-H , Kreuels M, Malten A, Martin D, Muster C, Nährig D, Platen R, Rödel I, Scheidler M, Staudt A, Stumpf H, Tolke D (2016) Rote Liste und Gesamtartenliste der Spinnen (Arachnida: Araneae) Deutschlands. 3. Fassung, Stand April 2008, einzelne Änderungen und Nachträge bis August 2015. Naturschutz und Biologische Vielfalt 70/4: 383-510 pdf

Bosmans R, Van Keer K (2017) Een herziene soortenlijst van de Belgische spinnen (Araneae). Nieuwsbrief van de Belgische Arachnologische Vereniging 32: 39-69 pdf

Branco V V, Morano E, Cardoso P (2019) An update to the Iberian spider checklist (Araneae). Zootaxa 4614: 201-254 pdf

Esyunin S L, Efimik V E (1996a) Catalogue of the spiders (Arachnida, Aranei) of the Urals. KMK Scientific Press, Moscow, 228 pp. pdf

Gajdoš P, Svatoň J, Sloboda J (1999) Katalóg pavúkov Slovenska. Catalogue of Slovakian spiders. Ústav kr. ekol. SAV, Bratislava, 337 pp.

Helsdingen P J van (2025a) Catalogus van de Nederlandse spinnen. Versie 2025.1. 249 pp. pdf

Isaia M, Tolve M, Pantini P (2025) Araneae.it: 2.0: the new updated version of the digital catalog of the Italian spiders and other arachnids (Arachnida: Araneae, Opiliones, Scorpiones, Pseudoscorpiones, Palpigradi, Solifugae). Fragmenta Entomologica 57: 197-204 pdf

Knoflach B, Thaler K (1998) Kugelspinnen und verwandte Familien von Österreich: ökofaunistische Übersicht (Araneae: Theridiidae, Anapidae, Mysmenidae, Nesticidae). Stapfia 667-712 pdf

Koponen S, Fritzén N R, Pajunen T (2016) Checklist of spiders in Finland (Araneae). 6th version, December 2016, online at http://biolcoll.utu.fi/arach/checklist_of_spiders_in_Finland.htm pdf

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 121: 203-230 pdf

Kronestedt T (2001) Checklist of Spiders (Araneae) in Sweden [Preliminary version February 2001] pdf

Lavery A (2019) A revised checklist of the spiders of Great Britain and Ireland. Arachnology 18: 196-212 pdf

Le Peru B (2007) Catalogue et répartition des araignées de France. Revue Arachnologique 16: 1-468 pdf

Locket G H, Millidge A F (1953) British spiders. Vol. II. Ray Society, London, 449 pp. pdf

Maurer R, Hänggi A (1990) Katalog der schweizerischen Spinnen. Documenta Faunistica Helvetiae 12 pdf

Naumova M, Blagoev G, Deltshev D (2021) Fifty spider species new to the Bulgarian fauna, with a review of some dubious species (Arachnida: Araneae). Zootaxa 4984: 228-257 pdf

Pajunen T, Väisänen R A (2015) First records of spiders (Araneae) Baryphyma gowerense (Locket, 1965) (Linyphiidae), Entelecara flavipes (Blackwall, 1834) (Linyphiidae) and Rugathodes instabilis (O. P.-Cambridge, 1871) (Theridiidae) in Finland. Memoranda Societatis pro Fauna et Flora Fennica 91: 44-50 pdf

Polchaninova N, Prokopenko E (2019) An updated checklist of spiders (Arachnida: Araneae) of Left-Bank Ukraine. Arachnologische Mitteilungen 57: 60-64 & App pdf

Ponomarev A V (2022) Spiders (Arachnida: Araneae) of the southeast of the Russian Plain: catalogue, the fauna specific features. SSC RAS Publishers, Rostov-on-Don, 640 pp. pdf

Roberts M J (1995) Collins Field Guide: Spiders of Britain & Northern Europe. HarperCollins, London, 383 pp. pdf

Rozwałka R, Stanska M (2008) Check-list of spiders (Araneae) of Poland. 1. December 2008. online at http://www.arachnologia.edu.pl/en/species/8-spiders-of-poland.html pdf

Růžička V, Řezáč M (2022a) Seznam pavouků České republiky. List of spiders of the Czech Republic. Online at https://www.arachnology.cz/seznam-pavouku-cr-26.html and https://www.arachnology.cz/en/seznam-pavouku-cr-26.html pdf

Sammet K, Martinez M R, Tali K, Melts I (2023) New records of arthropods from the priority Natura 2000 habitats in Estonian coastal areas. Check List 19: 1029-1048 pdf

Scharff N, Gudik-Sørensen O (2006) Katalog over Danmarks edderkopper (Araneae). Catalogue of the spiders of Denmark (Araneae). Entomologiske Meddelelser 74: 3-71 pdf

Szinetár C, Kovács P (2013) Pókfaunisztikai vizsgálatok a szentbékkállai Fekete-hegyen [The arachnological results of the 5th Hungarian Biodiversity Day at Fekete Hill (Balaton Uplands)]. Folia Musei Historico-Naturalis Bakonyiensis 29: 65-72 pdf

Weiss I, Petrișor A (1999) List of the spiders (Arachnida: Araneae) from Romania. Travaux du Muséum National d’Histoire Naturelle “Grigore Antipa” 41: 79-107 pdf

Wiehle H (1937) Spinnentiere oder Arachnoidea, VIII. 26: Familie Theridiidae oder Haubennetzspinnen (Kugelspinnen). Die Tierwelt Deutschlands 33: 119-222 pdf

WSC (2026) World Spider Catalog. Version 27. Natural History Museum Bern, online at http://wsc.nmbe.ch (13.2.2026) doi: 10.24436/2 pdf

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