A New Occurrence of Ditremaster (Irregular Echinoid) from the Eocene Kapuradi Formation, Barmer Basin, Western Rajasthan, India
S. L. Nama *
Department of Zoology, Jai Narain Vyas University, Jodhpur, Rajasthan, India.
Annu Kuldeep
Department of Zoology, Jai Narain Vyas University, Jodhpur, Rajasthan, India.
Anjali Rathore
Department of Zoology, Jai Narain Vyas University, Jodhpur, Rajasthan, India.
*Author to whom correspondence should be addressed.
Abstract
A previously unreported small spatangoid echinoid referable to the genus Ditremaster (Munier- Chalmas, 1885) has been identified from the Eocene Kapuradi Formation. The specimen was discovered from Kapuradi and Bhadkha localities in the Barmer Basin, Western Rajasthan, India. Thirty-eight specimens were recovered from the Fuller’s Earth horizons at Kapuradi and Bhadkha. All exhibit diagnostic characters of Ditremaster. The sample is derived from the Fuller's Earth horizon of the Kapuradi Formation, a clay-rich unit that has previously gone unrecorded for echinoids. This finding indicates a low-energy, shallow marine setting with soft clayey substrate in the Early Eocene Kapuradi Formation. This finding indicates previously unrecognised dispersal routes and environmental tolerance of spatangoids along the Western Indian margin during the Eocene. This discovery also widens Ditremaster's known paleogeographic distribution beyond the Middle Eocene of Kutch, Gujarat, where the genus was initially described.
Keywords: Spatangoida, Ditremaster, Eocene, Kapuradi formation, Barmer basin