Classification and Evolution of the Late Triassic Megalodontid Fauna in Western China

The Late Triassic megalodontids are unusual group of molluscan bicalues.They are characterized by their large sizes,thick shell walls(hight ratio of hone/soft tissue) with massive hinge plates,and strong,amorphous intensive-protruding hinge tooth.And they are considered the typical fauna in the Tethys Realm.

The Qinghai-Xizang Plateau (Tibetan Plateau) is one of the few regions in the Late Triassic megalodontids are most widely distributed.Forty-three species belonging to 10 genra are and 2 Megalodontidac,including 1 endemic genus and 16 species in 7 genra and 2 families have been found in the study area.Among them,31 species in 7 genera are referred to Megalodontidae,including 1 endemic genus and 16 endemic species;whereas 12 species in 3 genera are referred to Dicerocardiidae,and among them 9 species are endemics.These fossils are distributed in the area among the Tanggula Mts.,Kunlun Mts.,Bayan Har Mts.,and Taniantaweng Mts.,with altitude of 4500 to 5400 meters(Figure 1).However,these fossils have not been found south to the Hengduan Mountains.Geotectonically,the Late Triassic megalodtid fossils are distributed in the Qamdo Landmass between the Ganzi-Litang Suture Zone and bangong Co-Nujiang River Suture Zone,south to which no fossils of this kind have ever been found so far.

Chapter 1   Introduction
Chapter 2   Distribution and taphonomic status of late Triassic megalodontids in western China
Chapter 3   Life habit and functional morphology of Late Triassic megalodontids 
Chapter 4   Classification and evolution of Triassic megalodontids 
Chapter 5   Palaeogeographic Significances of  megalodontids 
Chapter 6   Systematic Palaeontology
References
English Abstract
Explanation of Plates