Eocene spiders from the Isle of Wight with preserved respiratory structures

Abstract

A new fossil spider, Vectaraneus yulei gen. et sp. nov., from the Eocene Bembridge Marls Insect Bed of the Isle of Wight, shows internal anatomy, including book lungs and tracheae, preserved by calcium carbonate replacement. The wide, medially positioned, tracheal spiracle and large tracheae which enter the prosoma are adaptations for an amphibious mode of life. The spider is placed in Cybaeidae Simon, 1898, Argyronetinae Menge, 1869, a subfamily which includes the Recent European Water Spider, Argyroneta aquatica (Clerck, 1757). The only previously described Bembridge Marls spider, Eoatypus woodwardii McCook, 1888, is redescribed; it is unrelated to Vectaraneus. The holotype of Argyroneta antiqua Von Heyden (1859) is redescribed; it is not an Argyroneta. Specimens referred to A. antiqua by Bertkau (1878) probably belong in Argyronetinae Menge, 1869, and this subfamily is emended herein.