Thursday, January 24, 2013

Pelican Spiders ( Assassin Spider)

Pelican Spiders ( Assassin Spider) | Pelican spiders are small (but not tiny) in size (less than 5 mm in body length), and usually brown or red-brown in colour. They are instantly recognisable by the remarkable shape of the cephalothorax and pars cephalica (head-region), the latter of which is elevated on top of a long 'neck'. The chelicerae are concomitantly elongate and spear-like, armed with a distal row of peg teeth which are used to impale their spider prey. The combination of a long neck and long chelicerae makes these spiders distinctly 'pelican-like' in appearance, hence the common name.

Archaeidae also possess eight eyes and long legs with a particularly long patella on leg I. The female genitalia are haplogyne with multiple spermathecae, and the male pedipalp is bulbous with a sinuous distal embolus and associated sclerites. The males of Australian pelican spiders also possess a dark dorsal scute on the abdomen. Males and females of most species possess two or three pairs of dorsal lumps or tubercles on the abdomen.
ralia, pelican spiders are usually found within temperate, subtropical or montane tropical rainforest, where they live within dense, low-growing vegetation, leaf litter, or on moss growing on logs or tree trunks. In south-western Western Australia, pelican spiders are rare, and are usually found in dense undergrowth, including coastal and montane heathland. The spiders build a line of silk at night, from which they hang upside-down to wait for their spider prey. The extremely long chelicerae, which are armed with peg teeth opposite the fangs, are used to spear and impale
Pelican spiders are cryptic and extremely well-camouflaged in nature, looking like inconspicuous seeds or pieces of organic debris lodged in vegetation - a disguise heightened by their ability to 'sway' from side-to-side in the breeze and when disturbed (similar to Mantodea and Phasmatodea among the insects).
Five archaeid species have been described from Australasia, although many new species are known from New South Wales and Queensland, and a single new species is known from south-western Western Australia (M. Rix and M. Harvey, work in progress). Pelican spiders are also diverse in Madagascar and south-eastern South Africa.

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