Oldest orb weaver spider fossil found
British and Spanish researchers have discovered amber-enclosed fossils of relatively modern orb-weaver spiders that lived 115 to 121 million years ago during the Lower Cretaceous period in Alava, northern Spain. This makes them the oldest proven specimens of this spider type to date.
The spider, which was named Mesozygiella dunlopi by David Penney from the University of Manchester and Vicente Ortuño from the Alcalá University, is already very similar to today's genera despite its great geological age: the new species only allowed itself to be based on their second pair of mouthparts - the pedipalps - delimit, the rest of the physique corresponds to that of their descendants. The fossil also indicates that a large number of orb-web spider species must have undergone rapid evolution during the Cretaceous period, which took place parallel to the development of flowering plants and the insect diversity dependent on them.
Even older spider fossils date from the Devonian 350 to 420 million years ago. Some of these fossils show the spinning glands, where the animals produce their silky threads. However, this evidence alone is not sufficient to assign the finds to the orb-web spiders, since spider silk can also be used as an egg sac or to cover burrows.
