New spiders (Araneae: Palpimanoidea) from the Jurassic Yanliao Biota of China

Several new spider specimens, belonging to the superfamily Palpimanoidea, are described from the Middle–Upper Jurassic Haifanggou Formation (early assemblage of the Yanliao Biota) of Inner Mongolia, China. Two new genera and species, and a new species in the genus Sinaranea Selden, Huang & Ren, 2008, are described. Caestaranea jurassica gen. et sp. nov. is described on the basis of several adult males, typified by boxing-glove shaped pedipalps, as well as females and juveniles. Onychopalpus thomisoides gen. et sp. nov. is the largest palpimanoid known, and its habitus resembles that of a crab spider (Thomisidae) in having large, laterigrade anterior legs with rows of macrosetae on the femora and a squat, rotund opisthosoma. However, the distinctive adult male pedipalp bears a pectinate claw, so the holotype specimen is a subadult male; the other specimens referred to this species are smaller juveniles. Three new specimens of Sinaranea metaxyostraca Selden, Huang & Ren, 2008, including two adult males, are described here, and the new species S. brevicrus sp. nov., which has shorter legs than the type species, is described from an adult male and an adult female. These new palpimanoids substantially increase the diversity of the superfamily in the Middle Jurassic, and the unusual Onychopalpus provides evidence for a different mode of life for these spiders.