The Archaeidae are a family of spiders that were at first only known from fossil records, the yellow translucent so-called Baltic amber can trap and preserve insects and other inverts for millions of years. It was presumed these spiders went extinct a long time ago, but a shocking discovery was made when one of these spiders was found in Madagascar, with more to be found in South Africa and Australia as well.
The Archaeid spiders have some bizarre features not found in other families of spiders: the long specialized mouthparts, two well-developed eyes, and a long “neck”. Let’s first look at the mouthparts of the spiders, the so-called “chelicerae”. Chelicerae are fang-bearing segments found in all spiders, used to inject the prey with venom. The extremely long chelicerae of the assassin spiders have developed a series of long spikes to keep the prey perfectly in place when grabbed.
Most spider-families have distinct eye-orientation, sometimes used for basic identification. The assassin spiders have a specific eye-orientation as well: two well-developed eyes looking straight forward, and six not-so developed eyes. Thinking about ogre-faced spiders (Deinopidae), which use their two developed eyes to see in just moonlight, the orientation has to have something to do with the hunting habits of the assassins.