Estimating dispersal and evolutionary dynamics in diploporan blastozoans (Echinodermata) across the great Ordovician biodiversification event

Abstract

Echinoderms make up a substantial component of Ordovician marine invertebrates, yet their speciation and dispersal history as inferred within a rigorous phylogenetic and statistical framework is lacking. We use biogeographic stochastic mapping (BSM; implemented in the R package BioGeoBEARS) to infer ancestral area relationships and the number and type of dispersal events through the Ordovician for diploporan blastozoans and related species. The BSM analysis was divided into three time slices to analyze how dispersal paths changed before and during the great Ordovician biodiversification event (GOBE) and within the Late Ordovician mass extinction intervals. The best-fit biogeographic model incorporated jump dispersal, indicating this was an important speciation strategy. Reconstructed areas within the phylogeny indicate the first diploporan blastozoans likely originated within Baltica or Gondwana. Dispersal, jump dispersal, and sympatry dominated the BSM inference through the Ordovician, while dispersal paths varied in time. Long-distance dispersal events in the Early Ordovician indicate distance was not a significant predictor of dispersal, whereas increased dispersal events between Baltica and Laurentia are apparent during the GOBE, indicating these areas were important to blastozoan speciation. During the Late Ordovician, there is an increase in dispersal events among all paleocontinents. The drivers of dispersal are attributed to oceanic and epicontinental currents. Speciation events plotted against geochemical data indicate that blastozoans may not have responded to climate cooling events and other geochemical perturbations, but additional data will continue to shed light on the drivers of early Paleozoic blastozoan speciation and dispersal patterns.

The Fezouata Shale Formation biota is typical for the high latitudes of the Early Ordovician—a quantitative approach

“…The high β-diversity values in our results concur with recent studies showing high dissimilarity throughout the Early Ordovician on a global scale (Penny and Kröger 2019). It is important to note that the Early Ordovician is marked by the beginning of environmental changes and increases in animal dispersal that would eventually become more pronounced during the Middle Ordovician (Miller 1997; Servais et al 2014; Lee and Riding 2018; Edwards 2019; Lam et al 2021). In this context, the patterns we recovered may suggest that the ecosystems of the Early Ordovician in the higher latitudes were still dictated by processes reminiscent of those taking place during the Cambrian to some extent (Servais et al 2014; Rasmussen et al 2016; Lee and Riding 2018; Saleh et al 2022a).…”

Estimating ancient biogeographic patterns with statistical model discrimination

“…Much of the paleobiogeographic discourse in recent years revolves around determining the global immigration and emigration of individual clades using phylogenetic‐centered methods (e.g., Matzke, 2013; Lam, Stigall, & Matzke, 2018; Lam, Sheffield, & Matzke, 2021; Gates, Gorscak, & Makovicky, 2019; Ding et al, 2020; Landis, Edwards, & Donoghue, 2021; Landis, Eaton, et al, 2021). Additionally, speciation and extinction rates among clades is an area of biogeographic interest for ecological turnover as well as phylogenetically because the methods mentioned above each require a time‐calibrated phylogeny that can be extremely affected by extinction rates (Bapst, 2013; Sanmartín & Meseguer, 2016).…”

“…Panel (a) shows the linear regression lines produced from using the Dice/Sorensen similarity index, whereas, Panel (b) shows the linear regression lines obtained from using the same data but analyzing with Euclidean distance. Panel (c) contains the equivalent linear regression lines from the phylogenetic community dissimilarity metric and Panel (d) has the phylogenetic topology of ceratopsid dinosaurs used in the phylogenetic community dissimilarity (PCD) Much of the paleobiogeographic discourse in recent years revolves around determining the global immigration and emigration of individual clades using phylogeneticcentered methods (e.g., Matzke, 2013;Lam, Stigall, & Matzke, 2018;Lam, Sheffield, & Matzke, 2021;Gates, Gorscak, & Makovicky, 2019;Ding et al, 2020;Landis, Eaton, et al, 2021). Additionally, speciation and extinction rates among clades is an area of biogeographic interest for ecological turnover as well as phylogenetically because the methods mentioned above each require a time-calibrated phylogeny that can be extremely affected by extinction rates (Bapst, 2013;Sanmartín & Meseguer, 2016).…”

Absolute Paleolatitude of Northern Zealandia From the Middle Eocene to the Early Miocene

“…371 gives important information about the tectonic and paleoenvironmental evolution for the Tasman area (Alegret et al., 2021; Stratford et al., 2022; Sutherland et al., 2022), and here we also use it to constrain the absolute paleoposition of northern Zealandia during the Cenozoic. Accurate paleogeography is essential for understanding past climate dynamics (e.g., Donnadieu et al., 2006), the paleogeographic distribution of fossils (e.g., Lam et al., 2018, 2021; Middlemiss, 1979), and the absolute positions of land and ocean to constrain paleoclimate models (Herold et al., 2008; Hollis et al., 2019; Lunt et al., 2017).…”