Spatial Bias in the Marine Fossil Record

Abstract

Inference of past and present global biodiversity requires enough global data to distinguish biological pattern from sampling artifact. Pertinently, many studies have exposed correlated relationships between richness and sampling in the fossil record, and methods to circumvent these biases have been proposed. Yet, these studies often ignore paleobiogeography, which is undeniably a critical component of ancient global diversity. Alarmingly, our global analysis of 481,613 marine fossils spread throughout the Phanerozoic reveals that where localities are and how intensively they have been sampled almost completely determines empirical spatial patterns of richness, suggesting no separation of biological pattern from sampling pattern. To overcome this, we analyze diversity using occurrence records drawn from two discrete paleolatitudinal bands which cover the bulk of the fossil data. After correcting the data for sampling bias, we find that these two bands have similar patterns of richness despite markedly different spatial coverage. Our findings suggest that i) long-term diversity trends result from large-scale tectonic evolution of the planet, ii) short-term diversity trends are region-specific, and iii) paleodiversity studies must constrain their analyses to well-sampled regions to uncover patterns not driven by sampling.

Paleolatitudinal distribution of lithologic indicators of climate in a paleogeographic framework

“…However, latitude strips at or near the equator have larger areas than the polar ones (see fig. 1 in Vilhena & Smith, 2013), which leads to over-binning in high-latitude strips. Ideally, an equal-area gridding scheme would be created to correct spatial sampling bias in the dataset (Vilhena & Smith, 2013), and this could be considered in future work.…”

“…1 in Vilhena & Smith, 2013), which leads to over-binning in high-latitude strips. Ideally, an equal-area gridding scheme would be created to correct spatial sampling bias in the dataset (Vilhena & Smith, 2013), and this could be considered in future work. However, we used the simpler 5°× 5°binning so that our results are comparable to the previous study of Ziegler et al (2003).…”

“…A global †Author for correspondence: wenchao.cao@sydney.edu.au palaeomagnetic compilation of Earth's basin-scale evaporite records suggests that evaporite palaeolatitudes have varied to some degree over the past 2 billion years, with a relatively large difference between Cenozoic-Mesozoic times (a mean palaeolatitude of 23 ± 4°) and Devonian-Ediacaran times (a mean palaeolatitude of 14 ± 2°) (Evans, 2006). In addition, previous studies have rarely considered the effect of the uneven distribution of continental areas through time (Vilhena & Smith, 2013) and the implications of applying different global tectonic reconstruction models (Scotese & Barrett, 1990;Ziegler et al 2003) on latitudinal distribution of climate indicators.…”

Evolutionary Trends within Jurassic Ammonoids

“…Other biases such as the non-random geographic distribution of outcrops may affect the patterns observed (e.g. McGowan and Smith 2008;Vilhena and Smith 2013). However, in spite of bias, the fossil record provides a unique opportunity to study evolutionary trends extensively for different periods of time.…”

Estimation of Species Richness of Permian Foraminifera in Non-Parametric Methods and Investigation of Its Change Trend in Central Alborz, Western Tethys

“…Uhen [11] used the number of genera as amount of richness. Vilhena [12] measured species richness by counting the presence or absence of genera in intervals and compared it at palaeo latitudes. Ruban [13] used a similar method to calculate the richness of the Jurassic brachiopods.…”