How has our knowledge of dinosaur diversity through geologic time changed through research history?

Jonathan P Tennant; Alfio Alessandro Chiarenza; Matthew Baron

doi:10.7717/peerj.4417

How has our knowledge of dinosaur diversity through geologic time changed through research history?

PeerJ. 2018 Feb 19:6:e4417. doi: 10.7717/peerj.4417. eCollection 2018.

Authors

Jonathan P Tennant¹, Alfio Alessandro Chiarenza¹, Matthew Baron^{2

3}

Affiliations

¹ Department of Earth Science and Engineering, Imperial College London, London, UK.
² Department of Earth Science, University of Cambridge, Cambridge, UK.
³ Earth Sciences Department, Natural History Museum, London, UK.

Abstract

Assessments of dinosaur macroevolution at any given time can be biased by the historical publication record. Recent studies have analysed patterns in dinosaur diversity that are based on secular variations in the numbers of published taxa. Many of these have employed a range of approaches that account for changes in the shape of the taxonomic abundance curve, which are largely dependent on databases compiled from the primary published literature. However, how these 'corrected' diversity patterns are influenced by the history of publication remains largely unknown. Here, we investigate the influence of publication history between 1991 and 2015 on our understanding of dinosaur evolution using raw diversity estimates and shareholder quorum subsampling for the three major subgroups: Ornithischia, Sauropodomorpha, and Theropoda. We find that, while sampling generally improves through time, there remain periods and regions in dinosaur evolutionary history where diversity estimates are highly volatile (e.g. the latest Jurassic of Europe, the mid-Cretaceous of North America, and the Late Cretaceous of South America). Our results show that historical changes in database compilation can often substantially influence our interpretations of dinosaur diversity. 'Global' estimates of diversity based on the fossil record are often also based on incomplete, and distinct regional signals, each subject to their own sampling history. Changes in the record of taxon abundance distribution, either through discovery of new taxa or addition of existing taxa to improve sampling evenness, are important in improving the reliability of our interpretations of dinosaur diversity. Furthermore, the number of occurrences and newly identified dinosaurs is still rapidly increasing through time, suggesting that it is entirely possible for much of what we know about dinosaurs at the present to change within the next 20 years.

Keywords: Cretaceous; Dinosaurs; Diversity; Extinction; Jurassic; Macroevolution; Mesozoic; Paleobiology Database; Publication bias; Triassic.

Grants and funding

Jonathan P. Tennant was funded by a National Environmental Research Council PhD studentship. Alfio A. Chiarenza is funded by an Imperial College London Janet Watson Departmental PhD Scholarship. Funding for Matthew Baron was provided by a NERC/CASE Doctoral Studentship (NE/L501578/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.