Twenty new spider species (Arachnida: Araneae) from Late Cretaceous Kachin amber (Myanmar)

Twenty new species of extinct spiders belonging to 10 genera in five families from Late Cretaceous Kachin amber are reported.One new genus,Triangulum Jiang&Li,gen.nov.,of the family Theridiidae Sundevall,1833 was established with T.thutai Jiang&Li,sp.nov.as the type species.The remaining 19 new species are:Retrooecobius lwini Jiang&Li,sp.nov.,Zamilia arkari Jiang&Li,sp.nov.,Z.sheini Jiang&Li,sp.nov.,Z.shwayi Jiang&Li,sp.nov.from Oecobiidae Blackwall,1862;Furcembolus inzaliae Jiang&Li,sp.nov.from Pacullidae Simon,1894;Priscaleclercera chimei Jiang&Li,sp.nov.,P.foshou Jiang&Li,sp.nov.,P.hlaingi Jiang&Li,sp.nov.,P.kani Jiang&Li,sp.nov.,P.kyawae Jiang&Li,sp.nov.,P.thanae Jiang&Li,sp.nov.,P.thaungi Jiang&Li,sp.nov.from Psilodercidae Machado,1951;Bicornoculus aungi Jiang&Li,sp.nov.,B.wunnai Jiang&Li,sp.nov.,B.yarzari Jiang&Li,sp.nov.,Cymbioblemma ohnmari Jiang&Li,sp.nov.,Palpalpaculla phyui Jiang&Li,sp.nov.from Tetrablemmidae O.Pickard-Cambridge,1873;Burmatheridon cetani Jiang&Li,sp.nov.,Cretotheridion champoi Jiang&Li,sp.nov.,from Theridiidae.All species are described based on males.All types are deposited in the Institute of Zoology,Chinese Academy of Sciences(IZCAS)in Beijing,China.

Two new spider families from Late Cretaceous Kachin amber(Arachnida: Araneae)

Two new spider families from Late Cretaceous Kachin amber(Myanmar),Pilosarachnidae Jiang&Li,fam.nov.and Gigarachnidae Jiang&Li,fam.nov.,are described:Pilosarachne ju Jiang&Li,gen.&sp.nov.and Gigarachne bian Jiang&Li,gen.&sp.nov.Type specimens are deposited in the Institute of Zoology,Chinese Academy of Sciences in Beijing(IZCAS).Both families bear three tarsal claws and are most likely entelegyne.Diagnostic characters of extinct families in Kachin amber with uncertain relationships with extant fauna are listed and discussed.