A report of Sulcolithos variabilis trace-fossils in India

The burrowing or boring traces of polychaetes ascribed to Sulcolithos variabilis have been recorded in the Fort Member of the Jaisalmer Formation, Jaisalmer Basin, exposed near the Jethwai village area of Jaisalmer district, western Rajasthan, India.These traces are superficial and occur on firm calcareous grounds of yellowish medium-to fine-grained calcareous sandstone of the Fort Member as elongated, straight, or curved grooves, such as burrows or borings.They are mostly found with rounded ends, but sometimes these grooves are tapered at both ends.The Sulcolithos variabilis grooves range from 42 to 92 mm in length, 4 to 6 mm in width and 3 to 6 mm in depth.These trace-fossils in the Fort Member of the Jaisalmer Formation are interpreted as combined burrowing and boring behaviour traces, probably produced by polychaete worms.However, no in situ remains of polychaete worms have been found yet in the presently identified Sulcolithos variabilis grooves.This report represents the first documented instance of Sulcolithos variabilis burrowing and/or boring in India.