Sauropod Teeth from the Lower Cretaceous Luohandong Formation of Ordos Basin,Inner Mongolia

摘要

The Early Cretaceous Zhidan Group in the northern Ordos Basin,Inner Mongolia,yielded a large number of tetrapods,including turtles,choristoderes,crocodyliforms,psittacosaurs,stegosaurs,theropods and birds.Well-preserved sauropod teeth have been found in the Luohandong Formation,a middle-upper unit of the Zhidan Group.The large V-shaped wear facet,low slenderness index value,labial grooves,lingual ridge and concavity on the tooth crown suggest that these teeth are from titanosauriforms.Moreover,the presence of the prominent bosses on the lingual side of the tooth crown indicates these teeth should be identified as Euhelopus teeth further.The existence of Euhelopus in Ordos Basin(Inner Mongolia),Shandong Province and western Liaoning Province shows some connections about vertebrate faunas during Early Cretaceous in these areas.Other tetrapod groups such as turtles(Sinemys,Ordosemys),choristoderes(Ikechosaurus),psittacosaurs {Psittacosaurus) and birds(Cathayornis) provide more evidences for this viewpoint.