Posted for Mico Tatalovic

Arachnophobes may want to think twice before checking out the new 3D models of “scary ancient spiders” released today.

Russell Garwood, of Imperial College London, and his colleagues, used a new technique called high-resolution X-ray micro-tomography to scan two fossilised specimens of 300 million old arachnids called Cryptomartus hindi and Eophrynus prestvicii to produce the 3D computer models of what these creatures would have looked like. The aim of their study, soon to be published in Biology Letters, was to use the physical traits of these extinct animals to reveal how they lived (press release).

For example, from seeing that C. hindi’s first two legs were angled towards the front of the body, they deduced that it used these limbs to grab prey, suggesting it was an ambush predator. It may have been much like modern day crab spiders, which wait for insect prey at the edge of the flowers before grabbing them with similarly positioned legs.

The study also indicates that many of the morphological features seen in these ancient animals still exist in modern day relatives and some could even be used to provide evidence for evolutionary relatedness of some of these organisms. This new X-ray technique could be used to re-analyse already studied fossils to provide a clearer picture of how ancient extinct species lived and has “the potential … to revolutionise the study” of many fossils, Garwood’s team write.

Image: Cryptomartus hindi / Natural History Museum and Imperial College London