Collecting and Processing Fossil Ostracods

Extract

Introduction

Ostracods are by far the most abundant fossil arthropods. They are collected for many purposes and applications, such as palaeoenvironmental and palaeoecological analysis, dating and correlation of rock sequences, reconstructing past geographies, and for taxonomic and evolutionary studies. By virtue of their small size and calcified bivalve carapaces (Fig. 1), which are readily preserved, ostracods have an excellent fossil record (Fig. 2). Their valves (Fig. 3A-I) can be recovered in large quantities from samples of sediments and sedimentary rocks (Boomer et al., 2003 and references therein). The group occurs in marine environments from at least the Ordovician period and in non-marine settings since the Carboniferous if not earlier, and it is ecologically diverse today (Horne, 2003; Fig. 2). Not all groups of ostracods, however, are well represented as fossils. For example, the fossil record of most myodocopes is sporadic, largely due to weak shell calcification in many taxa, and that of semi-terrestrial taxa is so far non-existent, probably because of the poor preservation potential of the damp, organic-rich environments they inhabited.