Phylogenetic paleobiology: integrating fossils with phylogenetic trees

As models for the Tree of Life, evolutionary trees (called phylogenies) form the cornerstone of evolutionary (paleo)biology. Why are some groups of organisms more diverse than others? Do certain traits evolve faster or more frequently than others? What traits are associated with increased extinction risk? To address these kinds of questions, we must first have knowledge of genealogical relationships among lineages. Traditionally, paleontologists have relied on taxonomic data as a proxy. However, phylogenetic trees form the cornerstone of evolutionary biology, and recent methodological advances have greatly enhanced our ability to infer time-scaled phylogenies of fossil taxa and incorporate them directly in macroevolutionary analyses.

My research in this area concerns model-based approaches to inferring phylogenies of fossil species and how we use them to answer questions about patterns of large-scale evolutionary change. I specialize in statistical approaches such as Bayesian inference and Phylogenetic Comparative Methods (PCMs) to reconstruct evolutionary histories, quantify rates of trait evolution, and document patterns of lineage diversification in the fossil record (Wright, 2017a; Wright 2017b; Wright et al., 2020; Soul and Wright, 2020).

My interests have focused primarily on probabilistic “tip-dating” phylogenetic methods and testing hypotheses of ancestor-descendant relationships. I have published a number of case studies implementing these approaches (Wright 2017a, 2017b, Wright and Toom, 2017; Wright et al., 2020) and have also applied phylogenetic methods to quantify ecological patterns and dynamics associated with paleocommunity change (Cole et al., 2019). I have also explored the impact of different approaches to handling stratigraphic age uncertainty when estimating phylogenetic relationships and divergence times (Barido-Satoni et al., 2020). In this study, we evaluated the performance of several widely-used probabilistic methods for estimating time-scaled phylogenies under range of conditions typical for data sets comprised extinct lineages, such as Paleozoic fossil invertebrates, and show that phylogenetic inferences are more accurate when stratigraphic data are included, but only when morphological character sampling is moderate to high. Consequently, this work provides insight into understanding the limits of current approaches and also point to areas where additional work, more data, and new models are needed.

Current and future research in this area are focused on efforts to document the frequency in which ancestor-descendant pairs occur in paleontological data and how the fossil record can be used to understand patterns and processes of speciation in the fossil record. This issue is of particular importance to resolving major macroevolutionary questions, including whether speciation events occur primarily via “budding” or “bifurcating” lineage splitting, or by anagenetic (i.e., within-lineage) evolutionary change.

Representative publications

* Soul, L.C. and * Wright, D.F., Phylogenetic comparative methods: a user’s guide for paleontologists. In press for Elements in Paleontology.  Post-review preprint here

Wright, A.M, Wagner, P.J., and Wright, D.F., 2020, Testing character-evolution models in phylogenetic paleobiology: a case study with Cambrian echinoderms. In review for Elements in Paleontology, preprint available at: EcoEvoRxiv. doi:10.32942/osf.io/ykzg5, posted here

Barido-Sottani, J., van Tiel, N., Hopkins, M.J., Wright, D.F., Stadler, T. and Warnock, R.C.M., 2020, Ignoring fossil age uncertainty leads to inaccurate topology and divergence time estimates using time calibrated tree inference. Frontiers in Ecology and Evolution: doi: 10.3389/fevo.2020.00183. Online.

Cole, S.R., Wright, D.F., and Ausich, W.I., 2019, Phylogenetic community paleoecology of one of the earliest, complex crinoid faunas (Brechin Lagerstätte, Ordovician). Palaeogeography, Palaeoclimatology, Palaeoecology, 521: 82-98.

Wright, D.F., 2017, Phenotypic innovation and adaptive constraints in the evolutionary radiation of Palaeozoic crinoids. Scientific Reports, 7(1), 13745. doi:10.1038/s41598-017-13979-9.

Wright, D.F. and Toom, U. 2017, New crinoids from the Baltic region (Estonia): fossil tip-dating phylogenetics constrains the origin and Ordovician–Silurian diversification of the Flexibilia (Echinodermata). Palaeontology, 60: 893-910.

Wright, D.F. 2017, Bayesian estimation of fossil phylogenies and the evolution of early to middle Paleozoic crinoids (Echinodermata). Journal of Paleontology, 91: 799-814.

Ausich, W.I., T.W. Kammer, E.C.  Rhenberg, and D.F. Wright. 2015. Early phylogeny of crinoids within the Pelmatozoan clade. Palaeontology, 58, 937-952.

Wright, D.F. and A.L. Stigall, 2017, Geological drivers of Late Ordovician faunal change in Laurentia: investigating links between tectonics, speciation, and biotic invasions. PLoS ONE, 8(7): e68353. doi:10.1371/journal.pone.0068353