On future directions of Ordovician chitinozoan research

Abstract

Chitinozoans have been known to science for nearly a century. Due to their biostratigraphic utility, chitinozoans were intensively studied from the 1960s to the 1980s, and they have an important place in Ordovician stratigraphy nowadays, alongside graptolites and conodonts. However, identifying chitinozoans is often complicated due to poorly illustrated and documented type specimens. During the last decades, descriptions of new species have decreased significantly, whereas open nomenclature has been adopted widely. The affinity of chitinozoans has been discussed in several recent papers, but further exceptional specimens and the application of up-to-date study techniques are needed to understand their biological functioning. The Ordovician chitinozoan biozonal schemes were mostly established in the 1990s. With much more data subsequently reported, many biozones currently need revision, and possibly new useful zones could be established. Herein we discuss how to tackle the problems in chitinozoan research by building an open-access database and restudying the poorly documented type materials using advanced techniques. This would foster progress and facilitate studies in systematics, evolution, biostratigraphy, palaeogeography and the biological affinity of chitinozoans. Current trends and problems in chitinozoan researchTaxonomy. In total, 563 publications (excluding abstracts) related to chitinozoans have been analysed, and 1131 species from 57 genera have been erected (Fig. 1) according to . About two-thirds of all species were erected from the 1960s to