{{Short description|Species of spider}} {{Speciesbox | name = | image = Ibala arcus 299773765 540088596.jpg | image_caption = female | image2 = Ibala arcus 299773765 540088919.jpg | image2_caption = female | taxon = Ibala arcus | authority = (Tucker, 1923)<ref name="tucker1923b" /> | synonyms = {{Species list |Setaphis calviniensis|Tucker, 1923 }} }}
'''''Ibala arcus''''' is a species of spider in the family Gnaphosidae.<ref name="wsc" /> It is a southern African endemic species.<ref name="dippenaar2021c" />
==Distribution== ''Ibala arcus'' is distributed across Zimbabwe, Namibia, and South Africa.<ref name="dippenaar2021c" /> In South Africa, it is recorded from all provinces at altitudes ranging from 47 to 1,645 m above sea level.<ref name="dippenaar2021c" />
==Habitat and ecology== The species is a free-living ground dweller, sampled from the Grassland, Nama Karoo, Savanna, and Succulent Karoo biomes.<ref name="dippenaar2021c" /> It has also been sampled from maize fields.<ref name="dippenaar2021c" />
The species mimics velvet ants (Hymenoptera: Mutillidae) with whom they are often caught in pitfall traps.<ref name="dippenaar2021c" />
==Description== {{see also|Glossary of spider terms}}
female|thumb|center
''Ibala arcus'' is known from both sexes. It is a small spider with average total length of 4-6 mm. The carapace and legs are reddish brown, while the abdomen is black with four white spots dorsally joined to form two longitudinal white strips.<ref name="dippenaar2021c" />
==Conservation== ''Ibala arcus'' is listed as Least Concern by the South African National Biodiversity Institute due to its wide distribution range.<ref name="dippenaar2021c" /> The species is found in more than 10 protected areas.<ref name="dippenaar2021c" />
==Taxonomy== The species was originally described by Tucker in 1923 from Warmbaths in Limpopo as ''Setaphis arcus''.<ref name="tucker1923b" /> It was revised by Fitzpatrick (2009).<ref name="dippenaar2021c" />
==References== {{Reflist|refs= <ref name="wsc">{{cite web | url=https://wsc.nmbe.ch/species/11488 | title=Ibala arcus (Tucker, 1923) | publisher=World Spider Catalog | doi=10.24436/2 | accessdate=25 September 2025}}</ref> <ref name="dippenaar2021c">{{cite book | last1=Dippenaar-Schoeman | first1=A.S. | last2=Haddad | first2=C.R. | last3=Foord | first3=S.H. | last4=Lotz | first4=L.N. | year=2021 | title=The Gnaphosidae of South Africa. Part 2 (E-S) | publisher=South African National Survey of Arachnida Photo Identification Guide | pages=15 | doi=10.5281/zenodo.7197672}}{{Creative Commons text attribution notice|cc=by4}}</ref> <ref name="tucker1923b">{{cite journal | last=Tucker | first=R.W.E. | year=1923 | title=The Drassidae of South Africa | journal=Annals of the South African Museum | volume=19 | issue=2 | pages=321}}</ref> }}
==External links== * {{inaturalist taxon}}
{{Taxonbar|from=Q27502426}}
Category:Gnaphosidae Category:Spiders of South Africa Category:Spiders described in 1923 Category:Taxa named by R. W. E. Tucker