Scientists from the University of Kansas (USA) and the Nanjing Institute of Geology and Palaeontology (China) provided a description of new species of spiders Eoplectreurys gertschi, whose remains were found in Inner Mongolia Autonomous Region in north China, in the sediments of the age of about 165 million years.
Remains of spiders, relating to the Middle Jurassic, are fairly rare, because the unprotected soft tissue arachnids poorly preserved. The high quality of the discovered instance is probably largely due to the fact that the animal was buried under a layer of tiny particles of volcanic ash, which does not violated the integrity of the cuticle.
From the combination of outward signs of the authors have identified E. gertschi a family of spiders vosmiglazyh Plectreuridae, which today comprises 30 species in south-western United States, Mexico, Cuba and Costa Rica. Until now, scientists have known only two extinct species of the family: Palaeoplectreurys baltica, the age of about 45 million years, and even more “young» Plectreurys pittfieldi. Detection of E. gertschi, thus adds to the established duration of existence of this group of spiders just 120 million years.
Because now E. gertschi in China does not occur, it could be argued that in ancient times the range of representatives Plectreuridae was wider. According to one of the authors, Paul Selden (Paul Selden), reducing proliferation of spiders was associated with the onset of the glacial period.