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

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.

Formation binning: a new method for increased temporal resolution in regional studies, applied to the Late Cretaceous dinosaur fossil record of North America

“…2019; Mallon 2019); for example, the Dinosaur Park Formation alone accounts for ~20% of total North American dinosaur diversity (Eberth & Currie 2005; Tennant et al . 2018; Chiarenza et al . 2019).…”

Late Jurassic theropod dinosaur bones from the Langenberg Quarry (Lower Saxony, Germany) provide evidence for several theropod lineages in the central European archipelago

“…Late Jurassic terrestrial sediments have seen a long history of fossil exploration (e.g., Close et al, 2018;Tennant, Chiarenza & Baron, 2018), which led to the discovery of an amazingly high number of dinosaur bearing formations (e.g., McAllister Rees et al, 2004). Despite the great dinosaur diversity known from that age (e.g., Lloyd et al, 2008;Barrett, McGowan & Page, 2009;Mannion et al, 2011), regional gaps in our knowledge of Late Jurassic dinosaur faunas still do exist.…”

Peer Review #1 of "Late Jurassic theropod dinosaur bones from the Langenberg Quarry (Lower Saxony, Germany) provide evidence for several theropod lineages in the central European archipelago (v0.1)"

“…Late Jurassic terrestrial sediments have seen a long history of fossil exploration (e.g. Close et al, 2018;Tennant, Chiarenza & Baron, 2018), which led to the discovery of an amazingly high number of dinosaur bearing formations (e.g. McAllister Rees et al, 2004).…”