Largest fossil spider

The largest fossil spider currently known to science is the type specimen (a female) of the species Mongolarachne jurassica, which existed in northern China during the mid-Jurassic period 164 million years ago. Its carapace measures 9.31 mm by 6.83 mm, its opisthosoma (the abdominal section in spiders) measures 15.36 mm by 9.5 mm, and its total body length is approximately 24.6 mm, with its front legs reaching approximately 56.5 mm in length.

When the type specimen was initially discovered, its species was believed to be a member of the orb-weaver spider genus Nephila, which still exists today, and which would therefore have made this genus the longest-lived modern-day spider genus. Following the later discovery of a male specimen, however, the latter exhibited several anatomical features that indicated strongly that the species did not belong in Nephila after all, so a new genus was created specifically for it, and some researchers even house it within an entirely separate taxonomic family of its own.