Lacustrine deposits exposed at Daohugou, Inner Mongolia, China, have yielded superbly preserved vertebrate fossils. The fossil beds were first misinterpreted as of Early Cretaceous age, based on alleged occurrences of key fossils of the Jehol Biota. Compelling evidence revealed by more rigorous research involving regional biostratigraphy, radiometric dating, and paleontology supports the Middle Jurassic age of the fossil beds. Despite the awesome evidence for the Middle Jurassic age of the Daohugou beds, the age dispute has been resurrected recently by invoking an overturned stratigraphic sequence. A careful review of the data, however, found no evidence that this sequence has been overturned. In addition, many of the assumptions, on which the conjecture of the fossil beds being post- Middle Jurassic is imprudently based, are self-contradictory or otherwise misleading. Thus, the post- Middle Jurassic age of the Daohugou beds as an unfounded conclusion can readily be dismissed.
Three new species of fossil Palaeontinidae are described from Daohugou Village, Inner Mongolia, China: Daohugoucossus shii sp. nov., D. parallelivenius sp. nov., D. lii sp. nov. The diagnosis of Dao- hugoucossus Wang, Zhang and Fang, 2006 is revised. These materials are the first complete fossil palaeontinids in the Middle Jurassic of the world. Based on observation of these new specimens, Sc of this new genus has the following combined characters: joined with R at base, diverged near M separa- tion, coalesced with R before the nodal line, extended beyond the nodal line and fused with R1 before distal end. Due to the Sc characteristics mentioned above, the genus Liaocossus Ren, Yin and Dou, 1998 can be well distinguished from “Ilerdocossus-complex”.
Two well-preserved fossil dragonflies from the Late Mesozoic Yixian Formation, Liaoning Province, China are described and assigned to a new genus, Sopholibellula gen. nov. in Araripelibellulidae Bechly, 1996, closely related to the type genus Araripelibellula. This new genus differs from AraripelibeUula in the following characters： origins of RP and MA distinctly separated at arculus in both pairs of wings; anal loop wider and shorter, with Y-shaped veins inside; MA and IR2 not zigzag; several small intercalary veins present in the postdiscoidal area of hindwing; cells smaller and much more dense, especially in the apex and hind margin; bigger in size. Structures, including head, abdomen and parts of legs, were first described in details of this family.
A new genus with one new species and five new species of genus Amblomma of fossil ommatids are described and illustrated： Euryomma tylodes gen. et sp. nov., Amblomma cyclodonta sp. nov., Amblomma miniscula sp. nov., Amblomma porrecta sp. nov., Amblomma eumeura sp. nov., and Amblomma protensa sp. nov. All of them were collected from the Upper Jurassic or Lower Cretaceous Yixian Formation of western Liaoning, China. A key to the species of Amblomma is given. The wide epipleural space shows that Euryomma may be a primitive genus in Ommatidae. Many different species of Amblomma occurred within the same sedimentary horizon in this area could be environmental changes caused by frequent volcanic activities during the deposition of the Yixian Formation.
Three new fossil species of the genus Mesocupes of fossil cupedids, M. angustilabialis sp. nov., M. latilabialis sp. nov. and M. collaris sp. nov., are described from the Jiulongshan Formation of Inner Mongolia, China. These new species are the first three records of fossil Mesocupes in China as well as the oldest ones in the world now. This finding also extends the geographical distribution of this genus from Central to East Asia. In addition, based on the ratio of the length of the last to the penultimate abdominal ventrites of new beetles distinctly lower than that of the species from the Karabastau Formation, the age of Daohugou fossil-bearing beds might be older than that of Karatau assemblage and consequently of Middle Jurassic.
One new genus and three new species of the weevil family Eccoptarthridae (Curculionoidea), Leptocar polychaetus gen. et sp. nov., Abrocar macilentus sp. nov., Cretonanophyes punctatus sp. nov., are described and illustrated. They pertain to the Upper Jurassic or Lower Cretaceous Yixian Formation of western Liaoning Province, China. The host plants to the living eccoptarthrids and the floras in Yixian Formation indicate that those archaic eccoptarthrids possibly lived on conifers with a phylogenetic closeness to Cupressaceae. Besides, the early diversification of eccoptarthrids is discussed: origi- nated in Central or East Asia in the Late Jurassic, spread into Western Europe and South America during the Early Cretaceous, underwent a dramatic decline after the Early Cretaceous which likely was caused by competitive pressure and the displacement of their host plants.
