Ask someone to name a dangerously venomous spider and the likely answer you’ll get is ‘black widow.’ Perhaps funnel-web if you're in Australia. A number of people will erroneously point at tarantulas or other large hairy horrors.
Sexy doesn't always = dangerous
Chances are, no one will mention a six-eyed sand spider (Sicarius sp.). The reason for this is that these particular critters are generally only found far into the Southern African desert, imitating a patch of sand. They rarely come into contact with humans which, given what toxicological studies suggest about their venom is probably a very good thing.
You probably won't see one of these...
... because they can do this
And then this.
Generally, spiders dangerous to humans produce either neurotoxic venom (i.e. Your widows and wandering spiders) or cytotoxic (cell-killing) venom such as found in violin spiders. Analysis of Sicarius spp. venom however shows that it contains both cytotoxic components (which cause tissue necrosis) and haemotoxic components which destroy blood cells. This combination makes Sicarius potentially the most dangerous genus of spiders on earth. The thing is, despite this fact, there are no certain cases of human envenomation on record. Suspected bites have however led to limb loss through massive necrosis and in one case death by internal haemorhaging. What we know of how the venom operates suggests that additional effects of its action include a build up of damaged blood cells leading to kidney and liver failure, numerous blood clots and potentially aneurysms.
Coupled with the fact that no anti-venom exists this makes Sicarius a deadly but fascinating member of the very small group of spiders dangerous to humans.
Well, till next time, Happy Steeming!
The Wise Fox
image 1: http://blog.rozzerstarantulas.co.za/
image 2: https://bullter.deviantart.com/art/166-Sicarius-terrosus-87490600
image 3: https://makeagif.com/gif/six-eyed-sand-spider-burying-herself-sicarius-hahni-xiAbSo
image 4:http://www.pesteducation.com/CdSamples/Spider