{{Short description|Genus of spiders}} {{Italic title}} {{Automatic taxobox | name = Six-eyed Sand Spiders |image = Hexophthalma Unidentified IMG 2788.jpg |image_caption = ''Hexophthalma'' sp. from coastal Namibia |image2 = |image2_caption = |taxon = Hexophthalma |authority = Karsch, 1879<ref name=wsc/> |synonyms = |synonyms_ref = <ref name=wsc/> |diversity = 8 species |diversity_link = #Species |diversity_ref = <ref name=wsc/> }}
'''''Hexophthalma''''' is a southern African genus of spiders in the family Sicariidae.<ref name=wsc/> The English name '''six-eyed sand spiders''' is used for members of the genus,<ref name=Lotz18/> particularly ''Hexophthalma hahni''.
Species in the genus have dermonecrotic venom, and can potentially cause serious or even life-threatening wounds.<ref name=snyman2005 />
==Distribution== ''Hexophthalma'' is endemic to southern Africa, having been found only in Namibia, South Africa and Zimbabwe.<ref name=wsc/>
==Life style== <gallery mode=packed heights=140px> Hexophthalma hahni 305451503 550742892.jpg|''H. hahni'' Hexophthalma hahni 305451503 550744478.jpg Hexophthalma hahni 305451503 550744529.jpg </gallery>
Species of ''Hexophthalma'' are free-living ground dwellers that have the ability to stay for long periods beneath the soil surface. With the help of their legs, sand is rapidly thrown over their bodies, enabling them to completely disappear beneath the surface. The tufts of sickle-shaped setae on their abdomen and legs help in holding the sand covering in place.<ref name="dippenaar2021" />
Only during mating are males more active and aggressive, roaming around above ground in search of a mate. The egg cocoon is cup-like in shape and is buried in the sand.<ref name="dippenaar2021" />
==Description== {{see also|Glossary of spider terms}} Body size ranges 8-11 mm for both males and females. Colour of body and legs varies from light brown, reddish brown, dark brown or grey. The carapace is about as wide as long, with one or multiple rows of macro-setae on lateral borders. Dorsal macro-setae are arranged in a central group surrounded by 4-5 pairs of macro-setae lines. The six eyes typical for the family are arranged in three diads with anterior median eyes absent.<ref name="dippenaar2021" />
The labium is longer than wide, tapering distally and partially fused to the sternum. The chelicerae are fused at the base. The sternum is wider than long, posteriorly truncate, with three outer rows of longer macro-setae near the border and shorter macro-setae in the middle. The abdomen is rounded, slightly truncate posteriorly, with 3-6 paired transversal rows of macro-setae.<ref name="dippenaar2021" />
Leg femora are covered on the dorsal surface by macro-setae. The tibia has eight rows of pointed macro-setae and the tarsus lacks an onychium.<ref name="dippenaar2021" />
==Taxonomy==
The genus was first created in 1878 by Ferdinand Karsch as ''Hexomma'', with the sole species ''Hexomma hahni''. By 1879, though, Karsch had realized that this name had already been used in 1877 for a genus of harvestmen, so he published the replacement name ''Hexophthalma''.<ref name=wsc />
In 1893, Eugène Simon transferred ''Hexophthalma hahni'' to the genus ''Sicarius'', and ''Hexophthalma'' fell out of use, until a phylogenetic study in 2017 showed that the African species of ''Sicarius'', including ''Sicarius hahni'', were distinct, and revived the genus ''Hexophthalma'' for them.<ref name=MagaBresSant17/>
''Hexophthalma'' is one of three genera in the family Sicariidae, {{As of|2018|July|lc=yes}}.<ref name=WSC_f88/> It is placed in the same subfamily, Sicariinae, as ''Sicarius'':<ref name=MagaBresSant17/> {{clade |label1=Sicariidae |1={{clade |label1=Loxoscelinae |1=''Loxosceles'' |label2=Sicariinae |2={{clade |1=''Hexophthalma'' |2=''Sicarius'' }} }} }}
===Species=== Two new species were added to the genus in 2018, and one previously accepted species, ''H. testacea'', was synonymized with ''H. hahnii''. The number of species is expected to increase with further study. ''H. spatulata'' differs in a number of respects from other species in the genus, which thus may not be monophyletic.<ref name=Lotz18 />
{{as of|2025|9}}, this genus includes eight species:<ref name="wsc" /> {{Div col}} * ''Hexophthalma albospinosa'' <small>(Purcell, 1908)</small> – Namibia, South Africa * ''Hexophthalma binfordae'' <small>Lotz, 2018</small> – Namibia * ''Hexophthalma damarensis'' <small>(Lawrence, 1928)</small> – Namibia * ''Hexophthalma dolichocephalus'' <small>(Lawrence, 1928)</small> – Namibia * ''Hexophthalma goanikontesensis'' <small>Lotz, 2018</small> – Namibia * ''Hexophthalma hahni'' <small>(Karsch, 1878)</small> – Namibia, Zimbabwe, South Africa (type species) * ''Hexophthalma leroyi'' <small>Lotz, 2018</small> – South Africa * ''Hexophthalma spatulata'' <small>(Pocock, 1900)</small> – South Africa {{Div col end}}
==Venom== Species of ''Hexophthalma'' produce venom that can have necrotic (dermonecrotic) effects, capable of causing serious or even life-threatening wounds, particularly if the wound becomes infected or the venom spreads in the body. The necrotic effects are caused by a family of proteins related to sphingomyelinase D, present in the venom of all sicariid spiders. In this respect, the genus resembles ''Loxosceles'', the recluse spiders.<ref name=MagaBresSant17/><ref name=BinfWell03/>
However, most ''Hexophthalama'' species have only been studied ''in vitro'', and the detailed effects of their venom in humans and other vertebrates are unknown.<ref name=MagaBresSant17/> One case was officially confirmed in South America in 1992, in a 17-year-old who developed a dermonecrotic lesion.<ref name=azevedo2017 /> There are two suspected cases in Africa, for which the spider has not been identified; however, according to the victim's description, the culprit could be ''Hexophthalma spatulata''. One of the two victims lost his arm due to extensive tissue necrosis.<ref name=Newlands />
==References== <references>
<ref name="wsc">{{cite web | url=https://wsc.nmbe.ch/genus/5600 | title=Genus Hexophthalma | publisher=World Spider Catalog | doi=10.24436/2 | accessdate=27 September 2025}}</ref>
<ref name=azevedo2017>{{Cite journal|last1=Azevedo|first1=Raul|last2=Azevedo|first2=Francisco Roberto de|last3=Ramalho|first3=Relrison Dias|last4=Goldoni|first4=Paulo André Margonari|last5=Brescovit|first5=Antonio Domingos|date=2017-12-11|title=Acidentes causados por aranhas e escorpiões no Estado do Ceará, Nordeste do Brasil: casos subnotificados e superestimados baseados na distribuição geográfica das espécies|url=http://revistas.ufcg.edu.br/cfp/index.php/RPECEN/article/view/453|journal=Pesquisa e Ensino em Ciências Exatas e da Natureza|language=pt|volume=1|issue=2|page=144|doi=10.29215/pecen.v1i2.453|issn=2526-8236|doi-access=free}}</ref>
<ref name=BinfWell03>{{Citation |last1=Binford |first1=Greta J. |last2=Wells |first2=Michael A. |date=2003 |title=The phylogenetic distribution of sphingomyelinase D activity in venoms of Haplogyne spiders |journal=Comparative Biochemistry and Physiology B |volume=135 |issue=1 |pages=25–33 |name-list-style=amp |doi=10.1016/S1096-4959(03)00045-9 |pmid=12781970 }}</ref>
<ref name="dippenaar2021">{{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 Sicariidae of South Africa. Version 1 | publisher=South African National Survey of Arachnida Photo Identification Guide | pages=6 | doi=10.5281/zenodo.7162164}}{{Creative Commons text attribution notice|cc=by4}}</ref>
<ref name=Lotz18>{{Citation |last1=Lotz |first1=Leon |date=2018 |title=An update on the spider genus ''Hexophthalma'' (Araneae: Sicariidae) in the Afrotropical region, with descriptions of new species |journal=European Journal of Taxonomy |issue=424 |pages=1–18 |doi=10.5852/ejt.2018.424 |doi-access=free }}</ref>
<ref name=MagaBresSant17>{{Citation |last1=Magalhães |first1=I.L.F. |last2=Brescovit |first2=A.D. |last3=Santos |first3=A.J. |date=2017 |title=Phylogeny of Sicariidae spiders (Araneae: Haplogynae), with a monograph on Neotropical ''Sicarius'' |journal=Zoological Journal of the Linnean Society |volume=179 |issue=4 |pages=767–864 |doi=10.1111/zoj.12442 |name-list-style=amp |doi-broken-date=12 July 2025 | url = https://academic.oup.com/zoolinnean/article/179/4/767/3076119}}</ref>
<ref name=Newlands>{{Cite web |last=Newlands |first=Gerald |title=Preliminary report on the medical importance of Sicarius (Araneae: Sicariidae) and the action of its venom |url=https://bibliotecadigital.butantan.gov.br/arquivos/45/PDF/19.pdf}}</ref>
<ref name=snyman2005>{{Citation |last1=Snyman |first1=C. |last2=Larsen |first2=N. |date=2005 |title=Spider bite and its treatment in southern Africa |journal=Occupational Health Southern Africa |volume=11 |issue=2 |pages=22–26 |url=http://www.occhealth.co.za/?/viewArticle/744 |access-date=2018-07-23 |name-list-style=amp }} – includes southern African ''Sicarius'', now ''Hexophthalma''</ref>
<ref name=WSC_f88>{{citation |title=Family Sicariidae Keyserling, 1880 |work=World Spider Catalog |publisher=Natural History Museum Bern |url=http://www.wsc.nmbe.ch/family/88 |access-date=2018-07-17 }}</ref>
</references>
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Category:Sicariidae Category:Araneomorphae genera