Revision of the Clam Shrimp Genus Magumbonia from the Upper Jurassic of the Luanping Basin,Hebei,Northern China

The diverse clam shrimp Nestoria-Keratestheria fauna is widely distributed in the Dabeigou Formation in northern Hebei and eastern Inner Mongolia of China.Its important component genus Magumbonia from the Dabeigou Formation in the Luanping Basin,northern Hebei,China,is revised on the basis of a scanning electron microscope(SEM)examination of the type species M.jingshangensis Wang,1984,which revealed morphological features not recognized previously.These include coarse reticulation on the umbo and prominent growth lines ornamented with densely spaced,small tubercles andfinelirae.