中国科学院南京地质古生物研究所机构知识库

The new boultoniid genus Dilatofusulina is established based on specimens from the Lopingian (Upper Permian) Gyanyima Formation in southern Tibet, China. This genus is somewhat similar to Codonofusiella and Parananlingella, but it is distinct in having a rapidly expanding but fully coiled last half volution. It probably represents an advanced offshoot of the Nanlingella-Parananlingella lineage in the family Boultoniidae. Based on its phylogenetic position and co-occurrence with Colaniella parva, this genus is referable to the late Changhsingian Stage (equivalent to the Palaeofusulina sinensis Zone in South China). To date, it is known from Gyanyima in southern Tibet, from Tianjun and Maduo Counties in Qinghai Province, China, and from Lamayuru in Himalayan Ladakh, India. These occurrences indicate a paleogeographic distribution limited to the northern and southern margins of the Tethys Sea.