Techniques for Systematic Collection and Processing of Vertebrate Microfossils from their Host Mudrocks: A Case Study from the Upper Triassic Tiki Formation of India

Abstract

ABSTRACT Vertebrate microfossils are valuable entities for the reconstruction of ancient ecosystems but difficult to find without using microscopes, resulting in a collection bias towards the macrofossils, which are easily visible to the naked eyes. The current study gives a comprehensive description of the protocols applied for systematic exploration and extraction of vertebrate microfossils. Initial assessment of the microsites for fossil-richness is carried out by spot sampling using coning and quartering, which is a technique applied for the first time. Subsequently, lithologs are prepared to ascertain the microfossil-bearing stratum, bulk samples are collected, screened by wet and dry sieving methods and residues examined under a microscope for extraction of vertebrate microfossils. These well-designed procedures are systematically applied for collection of vertebrate microfossils from the Upper Triassic Tiki Formation of the Rewa basin. More than 8000 kg of Tiki mudrocks collected as bulk samples, have yielded a rich and diverse array of vertebrate microfossils. The fauna incorporates different types of fresh water sharks, bony fishes, small temnospondyls, and varied r eptiles such as the archosauriforms, lepidosauromorphs, and cynodonts. These findings highlight the efficiency of the proposed methodology.