The Ediacaran Discoidal Fossil Aspidella from Sonia Sandstone of the Jodhpur Group, Marwar Supergroup, Western India, and Their Palaeobiological Implications
摘要
This study describes the newly found discoidal materials assignable to Aspidella (Ediacaran discoidal fossils) from the sandstone strata of Sonia Sandstone of the Jodhpur Group Marwar Supergroup in Sursagar area, Jodhpur, Western India. More than 100 specimens have been recorded here with variable sizes (small to large) and shapes (circular to ovate) of flat discoidal forms with a very sharp central boss on the sandstone bedding planes. In the Sursagar area, the majority of Aspidella specimens occur individually, while few specimens also overlap with the other Aspidella discs. Among these, some specimens are preserved with fronds or an overlying stem-like impression emanating from the central boss of the disc. This frond or stem-like impression attached to Aspidella discoidal forms is the first report in India. This study supports the interpretation of Aspidella as the buried basal holdfast structure of benthic frond-like organisms. The strata of Sonia Sandstone, which contain Aspidella discoidal fossil forms, are estimated to be of the Ediacaran age on the basis of their worldwide occurrences.