A large-sized caudal fin of the actinopteryigan Birgeria, from the Middle Triassic (Pelsonian, Anisian) Panxian Fauna in the Upper Member of the Guanlin Formation, Panxian County, Guizhou Province, China is described. It is the first report of Birgeria in the Panxian Fauna and represents the earliest fossil record of Birgeria in China. There are some specialized characters for this specimen in accordance with Bigeria: the speculated large size, narrow scales without ganoine ornament merely covering the posterodorsal portion of the caudal peduncle and the axial lobe of the caudal fin, single neural spine and haemal spine in caudal region, fulcra scales developed on the dorsal margin of the caudal fin, etc, which support the assignment of the current specimen to the genus Birgeria. Moreover, it distinguish from all known Birgeria species in its relatively large size (speculated total length over 2 m), a higher number of hypural (9), fulcras of the ventral margin of the caudal fin more developed and a bigger angle between the posterior margin of upper lobe and that of the lower lobe (>70º), but, a Birgeria sp. instead of a new species of Birgeria is assigned herein due to limited material. Birgeria is a kind of large carnivorous fish exsisting only in the Triassic ocean, which can be found from the Anisian Panxian Fauna to the Carnian Guanlin Fauna. The first appearance of Birgeria in China is later than that in West Tethys in Smithian, Early Triassic.

By analyzing the photos of scanning electron microscopy and thin section, intrusive mercury curve and materials of porosity and permeability, the reservoir characteristics of bioclast limestone member are discussed, which include petrologic feature, pore structure, reservoir space and reservoir properties of matter. Although the reservoir is deep buried, and primary pore was seriously destroyed by earlier compaction and cementation, the secondary pore developed very well by latter solution and dolomitization, especially dolomitization. Bioclast limestone member is quite capable of reserving oil and gas, and is classified as reservoir Ⅱ.

Dimethylsulfide is the major sulfur compound emitted from sea, which is mainly produced from marine phytoplankton. This article reviews the basic process of production and decomposition of dimethylsulfide in marine euphotic zone, including assimilatory sulfate reduction, production, accumulation and release of dimethylsulfoniopropionate as well as production and consumption of dimethylsulfide.